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diff --git a/44048-0.txt b/44048-0.txt new file mode 100644 index 0000000..d4ec076 --- /dev/null +++ b/44048-0.txt @@ -0,0 +1,8578 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 44048 *** + + LEGAL CHEMISTRY. + + + + A GUIDE + + TO THE + + DETECTION OF POISONS, + EXAMINATION OF TEA, STAINS, ETC., + + + + AS APPLIED TO + + CHEMICAL JURISPRUDENCE. + + + + TRANSLATED WITH ADDITIONS FROM THE FRENCH OF + + + A. NAQUET, + + _Professor to the Faculty of Medicine of Paris_. + + + BY + + + J. P. BATTERSHALL, Nat. Sc. D., F.C.S. + + + + _SECOND EDITION, REVISED, WITH ADDITIONS._ + + NEW YORK: + D. VAN NOSTRAND, PUBLISHER, + 23 MURRAY STREET AND 27 WARREN STREET. + + 1884. + + + + + COPYRIGHT. + D. VAN NOSTRAND. + 1876. + + + + +Transcriber's Note: + +Text originally marked up as bold is surrounded by *, text in italics by +_. Obvious printer errors have been corrected. A list of all other +changes can be found at the end of the document. In the Appendix of the +book, only the most obvious errors of punctuation were remedied. + + + + +PREFACE. + + +The importance of exact chemical analysis in a great variety of cases +which come before the courts is now fully recognized, and the +translation of this excellent little book on Legal Chemistry, by one of +the most distinguished French Chemists, will be appreciated by a large +class of American readers who are not able to consult the original. +While it is to be regretted that the author has not presented a much +more complete work, there is an advantage in the compact form of this +treatise which compensates, in some degree, for its brevity. + +The translator has greatly increased the value of the book by a few +additions and his copious index, and especially by the lists of works +and memoirs which he has appended; and while he could have further +increased its value by additions from other authors, we recognize the +weight of the considerations which induced him to present it in the form +given to it by the author. Some chapters will have very little value in +this country at this day, but the translator could not, with propriety, +omit anything contained in the original. + + C. F. CHANDLER. + + + + +PREFACE TO THE SECOND EDITION. + + +The principal change to note in this edition of the LEGAL CHEMISTRY is +the addition of a chapter on Tea and its Adulteration. The general +interest at present evinced concerning this species of sophistication +appeared to call for a simple and concise method of examination which +would include the requisite tests without entering upon an exhaustive +treatment of the subject. The translator's practical experience in the +testing of tea at the United States Laboratory of this city has enabled +him to make a few suggestions in this regard which, he trusts, may be of +use to those interested in food-analysis. Numerous additions have also +been made to the bibliographical appendix. + + J. P. B. + + + + +CONTENTS. + + + PAGE + INTRODUCTION 5 + + METHODS OF DESTRUCTION OF THE ORGANIC SUBSTANCES + + By means of Nitric Acid 8 + + " " Sulphuric Acid 9 + + " " Nitrate of Potassa 10 + + " " Potassa and Nitrate of Lime 12 + + " " Potassa and Nitric Acid 12 + + " " Chlorate of Potassa 13 + + " " Chlorine 13 + + " " _Aqua Regia_ 14 + + Dialysis 15 + + DETECTION OF POISONS, THE PRESENCE OF WHICH IS SUSPECTED. + + Detection of Arsenic 17 + + _Method used prior to Marsh's test_ 17 + + _Marsh's test_ 21 + + _Raspail's test_ 29 + + _Reinsch's test_ 30 + + Detection of Antimony 30 + + _Flandin and Danger's apparatus_ 32 + + _Naquet's apparatus_ 34 + + Detection of Mercury 36 + + _Smithson's pile_ 36 + + _Flandin and Danger's apparatus_ 37 + + Detection of Phosphorus 39 + + _Orfila's method_ 39 + + _Mistcherlich's method_ 40 + + _Dusart's method, as modified by Blondlot_ 40 + + _Fresenius and Neubauer's method_ 42 + + _Detection of Phosphorus by means of bisulphide of carbon_ 43 + + _Detection of Phosphorous Acid_ 45 + + _Estimation of Phosphorus_ 45 + + Detection of Acids 46 + + _Hydrochloric Acid_ 46 + + _Nitric_ " 47 + + _Sulphuric Acid_ 47 + + _Phosphoric_ " 48 + + _Oxalic_ " 49 + + _Acetic_ " 49 + + _Hydrocyanic_ " 50 + + Detection of alkalies and alkaline earths 52 + + Detection of chlorine, bromine and iodine 54 + + _Chlorine and Bleaching Chlorides_ 54 + + _Bromine_ 55 + + _Iodine_ 56 + + Detection of Metals 56 + + Detection of alkaloids and some ill-defined organic substances 65 + + _Stas's method_ 65 + + " " _as modified by Otto_ 69 + + " " " " _Uslar and Erdman_ 70 + + _Rodgers and Girdwood's method_ 71 + + _Prollius's method_ 72 + + _Graham and Hofman's method_ 73 + + _Application of Dialysis in the detection of Alkaloids_ 74 + + _Identification of the Alkaloid_ 74 + + _Identification of Digitaline, Picrotoxine and Colchicine_ 80 + + METHOD TO BE EMPLOYED WHEN NO CLEW TO THE NATURE OF THE + POISON PRESENT CAN BE OBTAINED 85 + + Indicative tests 86 + + Determinative tests 94 + + MISCELLANEOUS EXAMINATIONS 96 + + Determination of the nature and color of the hair and beard 96 + + _Determination of the color of the hair and beard_ 96 + + _Determination of the nature of the hair_ 99 + + Examination of Fire-arms 100 + + _The gun is provided with a flint-lock and was charged with + ordinary powder_ 100 + + _The gun is not provided with a flint-lock_ 103 + + Detection of human remains in the ashes of a fire-place 104 + + Examination of writings 105 + + Examination of writings, in cases where a sympathetic ink has + been used 110 + + Falsification of coins and alloys 112 + + Examination of alimentary and pharmaceutical substances 114 + + _Flour and Bread_ 114 + + _Fixed Oils_ 128 + + _a Olive Oil intended for table use_ 128 + + _b Olive Oil intended for manufacturing purposes_ 130 + + _c Hempseed Oil_ 130 + + _Tea_ 130 + + _Milk_ 137 + + _Wine_ 142 + + _Vinegar_ 147 + + _Sulphate of Quinine_ 148 + + Examination of blood stains 150 + + Examination of spermatic stains 158 + + APPENDIX 163 + + Books of Toxicology, etc. 163 + + Memoirs on Toxicology, etc. 168 + + INDEX 187 + + + + +LEGAL CHEMISTRY. + + +The term Legal Chemistry is applied to that branch of the science which +has for its office the solution of problems proposed in the interest of +Justice. These most frequently relate to cases of poisoning. When the +subject of the symptoms or anatomical lesions produced by the reception +of a poison is under consideration, the services of a medical expert are +resorted to; but when the presence or absence of a poison in the organs +of a body, in the _egesta_ of an invalid or elsewhere is to be +demonstrated, recourse is had to the legal chemist. Investigations of +this character require great practice in manipulation, and, however well +the methods of analysis may be described in the works on the subject, +there would be great danger of committing errors were the examination +executed by an inexperienced person. The detection of poisons, although +perhaps the most important, is not the only subject that may come within +the province of the legal chemist; indeed, it would be somewhat +difficult to define, _a priori_, the multitude of questions that might +arise. In addition to cases of supposed poisoning, the following +researches are most often required: + +1. The examination of fire-arms. + +2. The analysis of ashes, in cases where the destruction of a human +body is suspected. + +3. The detection of alteration of writings, and of falsification of +coins and precious alloys. + +4. The analysis of alimentary substances. + +5. The examination of stains produced by blood and by the spermatic +fluid. + +Each of these researches justly demands a more extended consideration +than the limits of this work would permit. The several subjects will be +treated as briefly as possible, and at the same time, so as to convey an +exact idea of the methods employed, leaving to the expert the selection +of the particular one adapted to the case under investigation. We will +first mention the methods used in the search for toxical substances. The +poisons employed for criminal purposes are sometimes met with in a free +state, either in the stomach or intestines of the deceased person, or in +the bottles discovered in the room of the criminal or the victim. Under +these circumstances, it is only necessary to establish their identity by +means of their chemical properties, as directed in the general treatises +on chemistry, or by their botanical, or zoological character, in case a +vegetable or animal poison, such as cantharides, has been administered. +Examinations of this class are extremely simple, the analysis of the +substances found, confined to a few characteristic reactions, being a +matter of no great difficulty. We will not here dwell longer upon this +subject, inasmuch as the analytical methods used are identical with +those employed in more complicated cases, with the sole difference that, +instead of performing minute and laborious operations in order to +extract the poisons from the organs in which they are contained, with a +view of their subsequent identification, we proceed at once to establish +their identity. The directions given in regard to complicated +investigations apply, therefore, equally well to cases of a more simple +nature. The detection of a poison mixed with the organic substances +encountered in the stomach, or absorbed by, and intimately united with +the tissues of the various organs is more difficult. If, however, other +information than chemical can be obtained, indicating the poison +supposed to be present, and the presence or absence of this one poison +is the only thing to be determined, positive methods exist which admit +of a speedy solution of the question. When, on the other hand, the +chemical expert has not the advantage of extraneous information, but is +simply asked,--whether the case be one of poisoning?--nothing being +specified as to the nature of the poison used, the difficulty of his +task is greatly increased. Up to the present time, the works on +Toxicology have, it is true, given excellent special tests for the +detection of particular poisons; but none have contained a reliable +general method, which the chemical expert could use with the certainty +of omitting nothing. Impressed with this need, we proposed, in 1859, in +an inaugural dissertation then presented to the Faculty of Medicine, a +general method, which, after some slight modifications, is now +reproduced. The special methods which allow of the detection of various +individual poisons will, however, first be indicated. In cases where the +poison is mixed with organic matter, the latter must be removed as the +first step in the investigation, as otherwise the reactions +characteristic of the poison searched for would be obscured. When the +poison itself is an organic substance, this separation is effected by +processes modified according to the circumstances. If the detection or +isolation of a metallic poison is to be accomplished, the most simple +method consists in the destruction of the organic substances. The +various methods for effecting this decomposition will now be described. + + + + +I. + +METHODS OF DESTRUCTION OF THE ORGANIC SUBSTANCES. + + +BY MEANS OF NITRIC ACID. + +In order to destroy the organic matters by this process, a quantity of +nitric acid equal to one and a half times the weight of the substances +taken is heated in a porcelain evaporating dish, the amount of acid +being increased to four or six times that of the organic substances if +these comprise the brains or liver. As soon as the acid becomes warm, +the suspected organs, which have previously been cut into pieces, are +added in successive portions: the organs become rapidly disintegrated, +brownish-red vapors being evolved. When all is brought into solution, +the evaporation is completed and the carbonaceous residue obtained +separated from the dish and treated either with water, or with water +acidulated with nitric acid, according to the nature of the poison +supposed to be present. + +Several objections to this method exist, the most serious of which is +based upon the fact that the carbonaceous residue, containing, as it +may, nitric acid, readily takes fire and may therefore be consumed, or +projected from the vessel. This objection is a grave one, and is not +always entirely removed by the continual stirring of the materials. +According to _M. Filhol_, the addition of 10 to 15 drops of sulphuric +acid to the nitric acid taken obviates the difficulty; not having +personally tested the question we cannot pronounce upon it. If it be the +case, this process is an advantageous one, as it is not limited in its +application, but can be used in the separation of all mineral poisons. + + +BY MEANS OF SULPHURIC ACID. + +The organic matter to be decomposed is heated with about one-fifth of +its weight of concentrated sulphuric acid, the complete solution of the +materials being thus accomplished. The excess of acid is next removed by +heating until a spongy carbonaceous mass remains. The further treatment +of this residue depends upon the nature of the poison supposed to be +present. If the sulphate of the suspected poison is a soluble and stable +compound, the residue is directly treated with water; if, on the +contrary, there is reason to think that the sulphate has suffered +decomposition, the mass is taken up with dilute nitric acid; if, +finally, the presence of arsenic is suspected, the residue is moistened +with nitric acid, in order to convert this body into arsenic acid. The +acid is afterwards removed by evaporation, the well pulverized residue +boiled with distilled water, and the solution then filtered. + +This method, when applied in the detection of arsenic, is objectionable +in that the carbonaceous residue, in contact with sulphuric acid, almost +invariably contains sulphurous acid, detected by means of permanganate +of potassa. This acid, being reduced in the presence of hydrogen, would +cause the formation of insoluble sulphide of arsenic, and in this way +prevent the detection of small amounts of arsenic by the use of Marsh's +apparatus. _M. Gaultier de Claubry_, indeed, states that he has not been +able to detect the presence of sulphurous acid in the carbonaceous +residue; but one affirmative result would, in this case, outweigh twenty +negative experiments. A further objection to this process consists in +the fact that the materials to be destroyed almost always contain +chlorides, which, in presence of sulphuric acid and an arsenical +compound, might determine the formation of chloride of arsenic, a +volatile body, and therefore one easily lost. This difficulty is +doubtless of a less serious nature than the preceding, as the operation +can be performed in a closed vessel provided with a receiver which +admits of the condensation of the evolved vapors; but even then the +process would be prolonged. The above method is still again +objectionable on account of its too limited application, it being +serviceable almost exclusively in cases where the poisoning has been +caused by arsenic, for, if applied in other instances, a subsequent +treatment would be necessary in order to redissolve the metal separated +from its decomposed sulphate. + + +BY MEANS OF NITRATE OF POTASSA. + +This method was formerly executed as follows: Nitrate of potassa was +fused in a crucible, and the substances to be destroyed added in small +portions to the fused mass. The organic matter soon acquired a pure +white color; owing, however, to the imperfect admixture of the organic +matter with the salt used for its decomposition, it was necessary to +take a large excess of the latter. + +The following process, suggested by _M. Orfila_, remedies this +inconvenience: The organs are placed in an evaporating dish, together +with one tenth of their weight of caustic potassa, and a quantity of +water varying with the weight of the substances taken. An amount of +nitrate of potassa equal to twice the weight of the organic matter is +next added, and the mixture evaporated to dryness. The residue is then +thrown by fragments into a Hessian crucible heated to redness, the +portions first taken being allowed to become perfectly white before more +is added. + +Whichever process has been employed, the fused mass is decanted into a +porcelain crucible, which has previously been heated in order to avoid +danger of breakage. The portion remaining in the vessel is taken up by +boiling with a small quantity of distilled water, and the solution so +obtained likewise added to the crucible. The mass is then heated with +sulphuric acid until all nitrous fumes are expelled, as these could give +rise to an explosion, when, in the search for arsenic, the substance is +introduced into Marsh's apparatus. As soon as the nitric acid is +completely expelled, the liquid is allowed to cool; the greater portion +of the sulphate of potassa formed now separating out in crystals. The +fluid is next filtered and the crystalline salt remaining on the filter, +washed, at first with a little distilled water, then with absolute +alcohol, which is subsequently removed from the filtrate by boiling. +This method is scarcely applicable otherwise than in the detection of +arsenic, as in other instances the presence of a large amount of +sulphate of potassa would be liable to affect the nicety of the +reactions afterwards used. Its application, even in the search for +arsenic, is not to be strongly recommended; on the contrary, the +separation of the potassa salt by filtration is indispensable, as +otherwise a double salt of zinc and potassium, which might be formed, +being deposited upon the zinc used in Marsh's apparatus, would prevent +the disengagement of hydrogen, and every chemist is too well aware of +the difficulty of thoroughly washing a precipitate, not to fear the +possible loss of arsenic by this operation. + + +BY MEANS OF POTASSA AND NITRATE OF LIME. + +In this method the organic materials are heated with water and 10 to 15 +per cent. of caustic potassa. As soon as disintegration is completed, +nitrate of lime is added, and the mixture evaporated to dryness. A +glowing coal is then placed upon the carbonaceous residue obtained: the +mass, undergoing combustion, leaves a perfectly white residue. This +residue dissolves in hydrochloric acid to a clear fluid which is then +examined for poisons. + +The above process possesses the undeniable advantage of completely +destroying the organic substances, at the same time avoiding the +introduction of sulphate of potassa, the presence of which impairs the +usefulness of the preceding method; but it necessitates the presence of +numerous foreign bodies in the substance to be analysed, and this should +be avoided. The _absolute purity_ of reagents is not always to be +attained, and the results of an analysis are the more certain, in +proportion as they are less numerous and more easily purified. + + +BY MEANS OF POTASSA AND NITRIC ACID. + +It has been proposed, instead of using nitrate of lime, to dissolve the +organic matter in potassa and then saturate the fluid with nitric acid. +This method is evidently more complicated than the simple treatment with +nitrate of potassa, and possesses, moreover, no advantages over the +latter process. + + +BY MEANS OF CHLORATE OF POTASSA. + +The organic materials are treated with an equal weight of pure +hydrochloric acid, and water added, so as to form a clear pulp. This +being accomplished, two grammes of chlorate of potassa are added to the +mixture at intervals of about five minutes. The fluid is next filtered, +and the insoluble residue remaining on the filter washed until the +wash-water ceases to exhibit an acid reaction. The filtrate is then +evaporated, an aqueous solution of sulphurous acid added, until the odor +of this reagent remains distinctly perceptible, and the excess of the +acid removed by boiling the solution for about an hour. The fluid is now +adapted to further examination for arsenic, or other metallic poisons. + +This method is one of the best in use, both chlorate of potassa and +hydrochloric acid being reagents easily procured in a state of great +purity; their use, however, is liable to the objection that they convert +silver and lead into insoluble chlorides. + + +BY MEANS OF CHLORINE. + +_M. Jacquelain_ suggests, in the search for arsenic, the decomposition +of the organic matters by means of a current of chlorine, and recommends +the following process: The organic substances are bruised in a mortar +and then macerated with water. The fluid so obtained, in which the +organic matter is held suspended, is next placed in a flask into which a +current of chlorine is passed until all the organic matter is deposited +in colorless flakes on the bottom of the vessel. The flask is then well +closed and allowed to stand for 24 hours, when the odor of the gas +should still be perceptible. The fluid is now filtered, the filtrate +concentrated by heating in a vessel which permits of the preservation of +the volatile chloride of arsenic possibly present, and then examined for +poisons. + +This process fails to possess the degree of generality desirable, and +presents the disadvantage of requiring considerable time for its +execution. + + +BY MEANS OF AQUA REGIA. + +This method is exceedingly simple: _Aqua regia_ (a mixture of two parts +of hydrochloric and one part of nitric acids) is placed in a tubular +retort provided with a receiver, and the organic materials, which have +previously been cut into small pieces, added; the reaction commences +immediately; if it is not sufficiently active, it is accelerated by a +gentle heat: lively effervescence now occurs, and the destruction of all +non-oleaginous substances is soon accomplished. The latter substances +alone are not immediately decomposed by _aqua regia_, which attacks them +only after prolonged action. As soon as the operation is concluded, the +apparatus is removed from the fire and taken apart. The fluid condensed +in the receiver is added to that remaining in the retort, and the whole +thoroughly cooled in an open dish. The fatty matters now form a solid +crust upon the surface of the fluid, which is removed and washed with +distilled water, and, the washings being added to the rest of the +solution, the latter is directly examined for metallic poisons. It is +recommended by _Gaultier de Claubry_, in cases where the detection of +arsenic is desired, to saturate and afterwards boil the suspected fluid +with sulphuric acid, in order to remove the nitric and hydrochloric +acids present. + + +DIALYSIS. + +The application of the dialytic method was first proposed by _Graham_. +By its use we are enabled to distinguish between two large classes of +bodies, viz., _colloids_ and _crystalloids_. Albumen, gelatine, and +analogous substances are typical of colloid bodies; crystalloid +substances, on the other hand, are those that are capable of +crystallization, either directly or in their compounds, or, in case they +are fluids, would possess this property when brought to the solid state. +Graham discovered that when an aqueous solution containing a mixture of +colloid and crystalloid substances is placed in a vessel having for its +bottom a piece of parchment or animal membrane, and this is immersed in +a larger vessel filled with water, all of the crystalloids contained in +the first vessel transverse the porous membrane and are to be found in +the larger vessel, the colloid bodies being retained above the membrane. +The organic matter to be eliminated in toxicological researches being +colloids, and the poisons usually employed being crystalloids, the value +of dialysis as a method of separation is evident. The process is +executed as follows: + + [Illustration: Fig. 1.] + +A wooden,--or better, a gutta-percha--cylinder (Fig. 1), 5 cubic +centimetres in height and from 20 to 25 c. c. in diameter, is employed. +A piece of moistened parchment is securely attached to one of the +openings of the cylinder, which, upon drying, shrinks and completely +closes the aperture. If its continuity becomes impaired, the pores of +the membrane should be covered with the white of an egg which is +subsequently coagulated by the application of heat. The organs +previously cut into small pieces, or the materials found in the +alimentary canal, etc., after having been allowed to digest for 24 hours +in water at 32°[A]--or, in dilute acids, if the presence of an alkaloid +is suspected,--are then placed in the upper vessel, which is termed the +dialyser. The whole should form a layer not over 2 cubic centimetres in +height. The dialyser is next placed in the larger vessel filled with +distilled water. In about 24 hours three-quarters of the crystalloid +substances present will have passed into the lower vessel. The solution +is then evaporated over a water-bath, and submitted to analysis. The +portion remaining in the dialyser is decomposed by one of the methods +previously described, in order to effect the detection of any poisonous +substances possibly present. Instead of the above apparatus, the one +represented in Fig. 2 can be employed. The fluid under examination is +placed in a bell-shaped jar, open at the top and closed below with a +piece of parchment, which is then suspended in the centre of a larger +vessel containing water. In other respects the operation is performed in +the same manner as with the apparatus represented in Fig. 1. + + [Illustration: Fig. 2.] + + [A] The degrees of temperature given in the text refer to the + centigrade Thermometer; their equivalents on the Fahrenheit scale can + be obtained by means of the formula: + + 9/5 C° + 32 = F°. + + --_Trans._ + + + + +II. + +DETECTION OF POISONS, THE PRESENCE OF WHICH IS SUSPECTED. + + +DETECTION OF ARSENIC. + +It is frequently required, in chemical jurisprudence, to institute a +search for arsenic in the remains of a deceased person, whose death is +supposed to have been caused by the reception of a poison. Under these +circumstances the poison is mixed with a mass of substances which would +obscure its characteristic properties, and it becomes necessary, in +order to accomplish its identification, to isolate it, and then, by +decisive reactions, determine its character. Three methods exist which +permit of this result; they are: + +1st. The method used prior to Marsh's test. + +2nd. Marsh's test. + +3rd. A method more recent than Marsh's, proposed by _M. Raspail_. + + +METHOD USED PRIOR TO MARSH'S TEST. + +The materials supposed to contain arsenic are boiled in water which +has been rendered strongly alkaline by the addition of pure potassa. The +fluid is then filtered, an excess of hydrochloric acid added, and a +current of sulphuretted hydrogen conducted through it. If arsenic be +present in the suspected fluid, it is soon precipitated as a yellow +sulphide. In dilute solutions the formation of the precipitate fails to +take place immediately, and only a yellow coloration of the fluid is +perceptible; upon slightly boiling the solution, however, the +precipitation of the sulphide is soon induced. The precipitate is +collected on a filter, well washed with boiling water, and then removed, +if present in a quantity sufficient to admit of this operation. It is +next dissolved in ammonia,[B] and the solution so obtained subsequently +evaporated to dryness on a watch-glass. The residue of sulphide of +arsenic is placed in a tube closed at one end containing nitrate of +potassa in a state of fusion: it is decomposed by this treatment into a +mixture of sulphate and arsenate of potassa, the reaction being +completed in about fifteen minutes. The mixture is now dissolved in +water, and lime water added to the solution: a precipitate of arsenate +of lime is formed, which is separated from the fluid by filtration, +dried, mixed with charcoal, and introduced into a second tube. A few +pieces of charcoal are then placed in the tube adjoining the mixture and +exposed to a red heat, the part of the tube containing the arsenical +compound being also heated. By this operation the arsenic acid is +reduced to arsenic, which is deposited upon the cold portion of the tube +in the form of a metallic mirror. This mirror is then identified by +subsequent reactions. The method just described is no longer in use, +although the precipitation of the arsenic by sulphuretted hydrogen is +still often resorted to in its separation from the other metals with +which it may be mixed. The destruction of the organic substances is, +however, accomplished by means of chlorate of potassa and hydrochloric +acid. To insure the complete precipitation of the arsenic, it is +advisable to conduct sulphuretted hydrogen through the solution, at a +temperature of 70° for twelve hours, and then allow the fluid to remain +in a moderately warm place, until the odor of the gas is no longer +perceptible, the vessel being simply covered with a piece of paper. The +precipitate is next freed from the other metals possibly present, as +directed in the general method of analysis, collected on a filter, and +dissolved in ammonia. The ammoniacal solution is evaporated on a watch +crystal, as previously described, and the residuary sulphide reduced to +metallic arsenic. This reduction is effected by a process somewhat +different from the one previously mentioned: the residue is fused, in a +current of carbonic acid gas, with a mixture of carbonate of soda and +cyanide of potassium. The apparatus employed is represented in Fig. 3: +_a_, is an apparatus producing a constant supply of carbonic acid. Upon +opening Mohr's clamp, _g_, the gas passes into the flask _h_, which +contains sulphuric acid; it is then conducted, by means of the tube _i_, +into the reduction tube _k_, which has an interior diameter of 8 mm. +This tube is represented, in half size, in Fig 4. + + [B] The sulphur, usually accompanying the precipitate of sulphide of + arsenic, is insoluble in ammonia.--_Trans._ + + [Illustration: Fig. 3.] + + [Illustration: Fig. 4.] + +The reduction is performed as follows: The sulphide of arsenic is +ground in a small mortar, previously warmed, together with 12 parts of a +mixture consisting of 3 parts of carbonate of soda and 1 part of cyanide +of potassium, both salts being perfectly dry. The powder thus obtained +is placed upon a piece of paper rolled in the form of a gutter, and +introduced into the reduction tube. The latter is then turned half round +its axis, so as to cause the mixture to fall in _de_ without soiling the +other parts of the tube. The paper is now withdrawn and the apparatus +mounted. Upon opening the clamp _g_, and strongly heating the mixture by +either the flame of a gas or an alcohol lamp, a mirror-like ring of +metallic arsenic is deposited at _h_, if this poison be present in the +substances under examination. When the coating is too minute to permit +of perfect identification, it should be driven by heat to a thinner part +of the tube; in this way it is rendered easily visible, being condensed +upon a smaller space. + +The above process possesses the advantage of not allowing arsenic to be +confounded with any other body; it also permits of a quantitative +estimation of the poison present. For this purpose, it is only necessary +to previously weigh the watch-crystal, upon which the ammoniacal +solution of sulphide of arsenic was evaporated, and to determine its +increased weight after the evaporation; the difference of the two +weighings multiplied by 0.8049, gives the corresponding weight of +arsenious acid, and by 0.6098, the weight of the corresponding amount of +metallic arsenic. + + +MARSH'S TEST. + +Marsh's test is based upon the reduction of arsenious and arsenic acids +by nascent hydrogen, and the subsequent transformation of these bodies +into water and arsenetted hydrogen, a compound from which the arsenic +can be readily isolated. When pure hydrogen is generated in a flask +having two openings, one of which is provided with a perforated cork +through which a safety-tube passes, the other with a tube bent at a +right angle and drawn out to a small point at the free extremity, the +evolved gas, if ignited, burns with a pale non-luminous flame. The air +should be completely expelled from the apparatus before igniting the +gas. Upon bringing a cold porcelain saucer in contact with the point of +the flame, only water is formed. If, however, a small quantity of a +solution containing arsenious or arsenic acids is introduced into the +apparatus by means of the safety-tube, arsenetted hydrogen is produced. +This gas burns with a bright flame, yielding fumes of arsenious acid. In +case a large amount of the poison is present, it can be recognized by +the appearance of the flame, and by inclining a glass tube towards it +upon which a portion of the arsenious acid becomes deposited. These +indications are, however, not distinguishable in presence of only a +small amount of arsenic, and the following distinctive properties of the +gas should be verified: + +1st. At an elevated temperature it is decomposed into its two +constituent elements. + + [Illustration: Fig. 5.] + + [Illustration: Fig. 6.] + +2nd. The combustibility of the constituents differs: the arsenic being +less combustible than the hydrogen, begins to burn only after the +complete consumption of the latter body has taken place. For this reason +the flame (Fig. 5) is composed of a dark portion _O_ and a luminous +portion _I_, which surrounds the first. The maximum temperature exists +in _O_ at the point of union of the two parts of the flame. Owing to an +insufficient supply of oxygen, the complete combustion of the arsenic in +this part of the flame is impossible, and if it be intersected by the +cold surface _A B_, that body is deposited as a brown spot, possessing a +metallic lustre. The metallic deposit originates, therefore, from the +decomposition of the arsenetted hydrogen by heat and from its incomplete +combustion. If the spot is not large, it fails to exhibit a metallic +lustre; an experienced chemist, however, will be able to identify it by +the aid of proper tests. Spots are sometimes obtained when the substance +under examination does not contain the least trace of arsenic. These may +be caused by antimony or by a portion of the zinc salt in the generating +flask being carried over by the gaseous current. This difficulty is +remedied by giving the apparatus the form represented in Fig. 6. _A_ is +the flask in which the gas is generated. The delivery-tube _I_ connects +with a second tube _H_, filled with asbestus or cotton; this is united +by means of a cork with a third tube _C_, made of Bohemian glass. The +latter tube is quite long, and terminates in a jet at its free end, +enclosed in tin-foil;[C] it passes through the sheet-iron furnace _R_, +supported upon _G_. The screen _D_ protects the portion _D E_ of the +tube _C_ from the heat. The gas disengaged is ignited at _E_ and the +porcelain dish _P_ is held by the hand in contact with the flame. The +apparatus being mounted, zinc, water and some sulphuric acid are placed +in the generating flask,[D] and the solution containing arsenious acid +added: the evolution of gas commences immediately. The tube _H_ serves +to retain any liquids that may be held suspended. The gas then passes +through the part _C D_ of the tube _C_, which is heated by placing a few +live coals upon the furnace _R_. The greater portion of the arsenetted +hydrogen is decomposed here, and is deposited on the cold part of the +tube, in a mirror-like ring. The small quantity of gas that escapes +decomposition, if ignited at _E_, produces a metallic spot on the dish +_P_. In order to determine that the spots are due to the presence of +arsenic, and not produced by antimony, the following tests should be +applied: + + [C] The fusing of the point of the tube is also prevented by + platinizing it. The tube is drawn out, its end roughened by filing, + and then immersed in solution of bichloride of platinum, so that a + drop or two of the fluid adheres. The point, upon heating, now + acquires a fine metallic lustre, and by repeating the operation a few + times a good coating of platinum is produced both on the exterior and + interior of the tube.--_Trans._ + + [D] The addition of a few drops of solution of bichloride of platinum + to the mixture of zinc, water and sulphuric acid is + advisable.--_Trans._ + +1. The color of the spots is distinctive: arsenical spots are brown and +exhibit a metallic lustre, whereas those originating from antimony +possess a black color, especially near their border. This difference is, +however, not perceptible when the deposits have a large surface. + +2. If the mirror be arsenical, it is readily volatilized from one part +of the tube to another, when the latter is heated, and a current of +hydrogen, or carbonic acid gas made to pass through it. Spots that are +due to the presence of antimony are much less volatile. + +3. If the tube is held in an inclined position so that a current of air +traverses it, and the part containing the arsenical mirror heated, the +arsenic oxidizes and arsenious acid is sublimed and deposited higher up +in the tube in the form of a ring, which exhibits octahedral crystals +when examined with a magnifying glass. This ring should be further +tested as follows: + +_a._ If it is dissolved in a drop of hydrochloric acid and a solution +of sulphuretted hydrogen added, a yellow precipitate of sulphide of +arsenic is formed. This compound is soluble in ammonia and in alkaline +sulphides, but insoluble in hydrochloric acid. + +_b._ If the ring is dissolved in pure water and an ammoniacal solution +of sulphate of copper added, a beautiful green precipitate ("_Scheele's +green_"), consisting of arsenite of copper, is produced. + +4. When produced by arsenic the spots are soluble in nitric acid, and +upon evaporating the solution so obtained to dryness, a residue of +arsenic acid, which is easily soluble in water, remains. If an +ammoniacal solution of nitrate of silver is added to the aqueous +solution of the residue, a brick-red precipitate is produced. Spots +consisting of antimony give, when treated with nitric acid, a residue of +an intermediate oxide, insoluble in water. + +5. Upon treating the spots with a drop of solution of sulphide of +ammonium, the sulphide of the metal present is formed: if sulphide of +arsenic is produced its properties, as enumerated above, can be +recognized. It may be added that the sulphide of antimony formed is +soluble in hydrochloric acid, and possesses an orange red color, whereas +sulphide of arsenic is yellow. + +6. When spots originating from arsenic are treated with a solution of +hypochlorite of soda (prepared by passing chlorine into solution of +carbonate of soda), they are immediately dissolved; if, on the other +hand, they are produced by antimony, they remain unaltered by this +treatment. + +Such are the properties exhibited by soluble compounds of arsenic when +treated by Marsh's process; the following precautions are, however, +necessary when this test is made use of in medico-legal examinations. + +1. If small white gritty particles, resembling arsenious acid, are +discovered in the stomach or intestines, they are directly introduced +into Marsh's apparatus. When this is not the case, the destruction of +the organic matter is indispensable even though, instead of the organs +themselves, the contents of the alimentary canal are taken. In the +latter instance, the solids are separated from the fluids present by +filtration, the solution evaporated to dryness and the residue united +with the solid portion; the organic matter is then destroyed by one of +the methods previously described. In the special case of arsenic, the +separation of the poison from the accompanying organic materials can be +accomplished by a process not yet mentioned which may prove to be of +service. The suspected substances are distilled with common salt and +concentrated sulphuric acid. By this operation the arsenic is converted +into a volatile chloride which distils over. The poison is isolated by +treating this compound with water, by which it is decomposed into +hydrochloric and arsenious acids. We must give preference, however, to +the method by means of chlorate of potassa and hydrochloric acid. + +2. The solution having been obtained in a condition suitable for +examination, the air is completely expelled from the apparatus by +allowing the gas to evolve for some time, and the suspected fluid then +introduced into the generating flask. Danger of explosion would be +incurred were the gas ignited when mixed with air.[E] + + [E] The effervescence of the mixture is prevented by _slowly_ adding + the arsenical solution to the generating flask. In order to avoid loss + of arsenetted hydrogen, the cold dish should be directly applied to + the flame even before the introduction of the suspected solution, and + its position changed at short intervals, so as to allow the deposit to + be formed on different parts.-_Trans._ + +3. It is indispensable, in applying this test, to have a second +apparatus in which only the reagents necessary to generate hydrogen are +placed: in this way, if no spots are now produced by the use of the +second apparatus, it is certain that those obtained when the first +apparatus is employed do not originate from impurities present in the +reagents used. + +It has come under the author's observation, however, that a sheet of +zinc sometimes contains arsenic in one part and not in another; in fact, +the shavings of this metal, as purchased for laboratory use, are often +taken from lots previously collected, and may therefore have been +prepared from several different sheets. If this be the case, it is +supposable that the zinc used in the second apparatus may be free from +arsenic, whereas the metal with which the suspected solution is brought +in contact may contain this poison; serious danger would then exist of +finding indications of the presence of arsenic in materials that did not +originally contain a trace of the metal. In order to obviate this +important objection, which might possibly place a human life in +jeopardy, we propose the following modifications: Pure mercury is +distilled and its absolute purity established. As the metal is a fluid +and is therefore homogeneous, it is evident if one portion be found +pure, the entire mass is so. Sodium is then fused under oil of naphtha, +in order to cause the complete admixture of its particles, and the +purity of the fused metal in regard to arsenic tested. An amalgam is +next prepared by uniting the mercury and sodium. This is eminently +adapted to toxicological investigations: in order to generate a supply +of very pure hydrogen, it is only necessary to place the amalgam in +water kept slightly acid by the addition of a few drops of sulphuric +acid, by means of which the disengagement of gas is rendered more +energetic.[F] + + [F] Owing to the impurities often occurring in zinc, the use of + distilled magnesium in Marsh's apparatus has also been suggested. This + metal is now to be obtained in a state of great purity; it is, + however, sometimes contaminated with silicium, which body likewise + gives rise to a metallic deposit, but one that is readily + distinguished from arsenical spots by its insolubility in nitric acid, + _aqua regia_, and in hypochlorite of soda. The presence of magnesium + causes the precipitation of the non-volatile metals possibly contained + in the fluid tested for arsenic.--_Trans._ + +It should be borne in mind that the solution introduced into Marsh's +apparatus must not contain organic substances, and that, in case their +destruction has been accomplished by means of nitric acid all traces of +this compound are to be removed. The sulphuric acid used should also be +completely freed from nitrous vapors. According to _M. Blondeau_, +nascent hydrogen in the presence of nitrous compounds converts the acids +of arsenic not into arsenetted hydrogen (As H{3}), but into the _solid_ +arsenide of hydrogen (As{4} H{2}). This latter compound, upon which pure +nascent hydrogen has no effect, is transformed into gaseous arsenetted +hydrogen by the simultaneous action of nascent hydrogen and organic +substances. These facts are of the greatest importance, for they might +possibly cause a loss of arsenic when it is present, as well as +determine its discovery when it is absent. + +The first case is supposable: should traces of nitric acid remain in +the solution, the arsenic would be transformed into solid arsenide of +hydrogen and its detection rendered impossible. The second case may also +occur: if the zinc placed in the apparatus contains arsenic, and the +sulphuric acid used contains nitrous compounds, the evolved gas will +fail to exhibit any evidence of the presence of arsenic, owing to the +formation of the solid arsenide of hydrogen. Upon adding the suspected +solution, which, perchance, may still contain organic substances, this +arsenide is converted into arsenetted hydrogen, and the presence of +arsenic will be detected, although the solution under examination was +originally free from this metal. + + +RASPAIL'S METHOD. + +M. Raspail suggests the following method for detecting arsenic: The +surface of a brass plate is rasped by filing. In this condition the +plate may be regarded as an innumerable quantity of voltaic elements, +formed by the juxtaposition of the molecules of zinc and copper. The +suspected materials are boiled with caustic potassa, the solution +filtered, a drop of the filtrate placed upon the brass plate, and a drop +of chlorine water added. If the plate is then allowed to stand for a +moment and the substance under examination contains arsenic, a +mirror-like spot is soon deposited upon its surface. In order to avoid +confounding this deposit with those produced by other metals, the +substitution of granulated brass for the plate is in some cases +advisable. The granulated metal is dipped successively in the suspected +solution and in chlorine water. The granules retain a small quantity of +the solutions and, owing to the action of the chlorine water, become +covered with metallic spots, if arsenic be present. They are then dried, +placed in a tube closed at one end, and exposed to the heat of an +alcohol lamp. In case the spots are arsenical, the metal volatilizes and +condenses in a ring upon the cold part of the tube, which is submitted +to the tests previously described. + +This method can hardly be of great service, inasmuch as it extracts the +poison from but a very small portion of the solution containing it: we +have not, however, personally tested its merits.[G] + + [G] The omission in the text of Reinsch's test should be supplied. + This test is based upon the fact that when solutions of arsenious acid + or an arsenide are acidulated with hydrochloric acid and boiled with + metallic copper, the latter becomes covered with a film consisting + largely of metallic arsenic: it is extensively employed in + chemico-legal examinations. The materials to be examined are + completely disintegrated by boiling with hydrochloric acid, and the + fluid filtered. Some pure copper gauze or foil, having a polished + surface, is then immersed in the boiling solution, and notice taken of + the formation of a grey deposit. If a coating be formed, fresh pieces + of the metal are added, so long as they become affected. The copper is + then withdrawn from the solution, thoroughly washed with water, and + dried, either by means of the water-bath or by pressing between + bibulous paper. It is next introduced into a dry tube, and heated over + a spirit lamp. The arsenic present volatilizes and is oxidized to + arsenious acid which forms a deposit, consisting of octahedral + crystals, on the cold part of the tubes. These are subsequently tested + by means of the reactions distinctive of arsenious acid. It need + hardly be added that the absolute purity of both the hydrochloric acid + and of the copper is to be carefully established. The deposit obtained + in the above operation was formerly regarded as pure arsenic, but it + has been proved to be an alloy consisting of 32 per cent. arsenic, and + 68 per cent. copper. Reinsch's test possesses the advantage of + requiring but little time for its execution, of being applicable to + complex organic mixtures, and of effecting the detection of a very + minute trace of the poison.--_Trans._ + + +DETECTION OF ANTIMONY. + +Strictly speaking the salts of antimony are more therapeutic than +poisonous in their action. In fact they usually act as emetics and, +under certain circumstances, may be taken in large doses without +incurring serious results. There are instances, however, in which their +action is truly toxical, and it becomes necessary to effect their +detection in the organs of a body. It should be remarked that these +salts, if absorbed, remain by a kind of predilection in the liver and +spleen. A special examination of these organs should therefore be +instituted, particularly if the fluids of the alimentary canal are not +at hand, which is frequently the case when some time has elapsed before +the investigation is undertaken. + +The remarks made in the preceding article concerning the distinctive +properties of arsenic and antimony need not be repeated here. The search +for antimony is likewise executed by aid of Marsh's apparatus. We will +confine ourselves to a description of a modification to this apparatus +proposed by _MM. Flandin_ and _Danger_, and employed in the separation +of antimony and arsenic, when a mixture of these metals is under +examination. Another process, by means of which we arrive at the same +result with greater certainty and by the use of a less expensive +apparatus, will then be mentioned. We will, however, first indicate the +preferable method of destruction of the organic substances. + +Were the decomposition performed by means of sulphuric acid, sulphate of +antimony, a slightly soluble salt and one not well adapted to the +subsequent treatment with nascent hydrogen, would be formed. In order to +obtain the metal in a soluble state, the formation of a double tartrate +of antimony and soda is desirable. This may be accomplished in the +following manner: + +1. A cold mixture of nitrate of soda, sulphuric acid, and the suspected +materials is prepared in the proportion of 25 grammes of the nitrate to +39 grammes of the acid, and 100 grammes of the substance under +examination. This mixture is heated and evaporated to dryness, and the +decomposition of the organic matter completed in the usual manner. The +carbonaceous residue obtained is pulverized, and then boiled with a +solution of tartaric acid. By this treatment the antimonate of soda +present is converted into a double tartrate of antimony and soda, which +is easily soluble in water. The solution is filtered and then introduced +into Marsh's apparatus. + +2. Another method consists in heating the substances under examination +with one half of their weight of hydrochloric acid for six hours on a +sand-bath, avoiding boiling. The temperature is then increased until the +liquid is in a state of ebullition, and 15 to 20 grammes of chlorate of +potassa, for every 100 grammes of the suspected matter taken, added in +successive portions, so that a quarter of an hour is required for the +operation. The liquid is next filtered, and the resinous matter +remaining on the filter well washed with distilled water; the washings +being added to the principal solution. A strip of polished tin is then +immersed in the liquid: in presence of a large amount of antimony the +tin becomes covered with a black incrustation: if but a minute quantity +of the metal is contained, only a few blackish spots are perceptible. +After the tin has remained immersed for 24 hours, it is withdrawn and +placed in a flask together with an amount of hydrochloric acid +sufficient for its solution in the cold. If, after several hours, +blackish particles are still observed floating in the liquid, they can +be dissolved in a few drops of _aqua regia_. The solution may then be +directly introduced into Marsh's apparatus. + + +APPARATUS PROPOSED BY FLANDIN AND DANGER. + + [Illustration: Fig. 7.] + +This apparatus consists of a wide necked jar _A_ (Fig. 7) for the +generation of the gas, the mouth of which is closed with a cork having +two openings. The safety tube _S_, which is funnel-shaped at its upper +extremity and has its lower end drawn out to a point, passes through one +of these apertures; the other opening contains the small delivery tube +_B_, open at both ends, and terminating in a point at its upper +extremity: it is also provided with lateral openings, in order to +prevent the solution being carried up to the flame. The second part of +the apparatus is the condenser _C_, 0.03 metre in diameter, and 0.25 +metre in length. This terminates at its lower extremity with a cone, and +connects at the side with the tube _T_, slanting slightly downwards. In +the interior of the condenser, the cooler _E_ is contained, the lower +end of which is nearly in contact with the sides of the opening _O_. The +combustion tube _D_, 0.01 metre in diameter, is connected by means of a +cork with the tube _T_; it is bent at right angles, and encloses the +tube _B_, in such a manner as to allow the evolved gas to burn in its +interior. The dish _F_ is placed beneath the opening _O_. If the gas +which burns in the combustion tube contains arsenetted hydrogen, water +and arsenious acid are produced. A portion of this acid is retained in +the tube _D_, the remainder is carried over, with the aqueous vapor, +into _C_, where it condenses, and finally falls into the dish _F_. Both +portions are subsequently examined by means of reactions necessary to +establish the presence of the acid. If the ignited gas contains +antimonetted hydrogen, water and an intermediate oxide of antimony are +formed. The latter compound is entirely retained in the tube _D_ +separated from the greater part of the arsenious acid, if this body be +present, and can be brought into solution by means of a mixture of +hydrochloric and tartaric acids. A fluid is then obtained which can be +introduced into Marsh's apparatus, or otherwise examined for antimony. + + +NAQUET'S APPARATUS. + + [Illustration: Fig. 8.] + +Although the separation of arsenic from antimony is the chief object in +making use of the apparatus proposed by Flandin and Danger, it is +evident that this result is not fully accomplished, since a small +portion of arsenious acid remains in the tube _D_ (Fig. 7), together +with the intermediate oxide of antimony. The following method secures +the complete separation of these metals: An amalgam of sodium and +mercury is introduced into the flask _A_, (Fig. 8), which is provided +with two openings. The tube _B_, terminating in a funnel at its upper +extremity, passes through one of these orifices. The other aperture +contains a cork enclosing the small tube _C_, which is bent at a right +angle and communicates, by means of a cork, with the larger tube _D_ +filled with cotton or asbestus. A set of Liebig's bulbs, _E_, containing +a solution of nitrate of silver, is attached to the other extremity of +this tube. The apparatus being mounted, the solution under examination +is slightly acidulated and introduced by means of the tube _B_ into the +flask _A_: the disengagement of gas begins immediately. If arsenic and +antimony are contained in the solution, arsenetted hydrogen and +antimonetted hydrogen are evolved. Both gases are decomposed in passing +through the solution of nitrate of silver contained in the Liebig bulbs: +the arsenetted hydrogen causes a precipitation of metallic silver, all +the arsenic remaining in solution as arsenious acid; the antimonetted +hydrogen is decomposed into insoluble antimonate of silver. After the +operation has continued for several hours, the apparatus is taken apart, +the nitrate of silver solution thrown on a filter, and the precipitate +thoroughly washed. An excess of hydrochloric acid is then added to the +filtrate, and the precipitate formed separated from the solution by +filtration, and well washed. The wash-water is added to the solution, +and the whole then examined for arsenic by means of Marsh's test. + +The precipitate formed in the nitrate of silver solution, which +contains antimonate of silver, is well dried, mixed with a mixture of +carbonate and nitrate of soda, and calcined in a porcelain crucible for +about three-quarters of an hour. The crucible is then removed from the +fire, and the cooled mass treated with hydrochloric acid until a drop of +the filtered fluid ceases to give a residue when evaporated upon a +watch-glass to dryness. A current of sulphurous acid is now conducted +through the filtered solution until the odor of this gas remains +persistent. The excess of acid is then removed by boiling, and the +solution placed in Marsh's apparatus and tested for antimony. + + +DETECTION OF MERCURY. + +If a mercurial salt exists in a considerable quantity in the substances +extracted from the alimentary canal, or ejected either by stools or +vomiting, it can be isolated by treating these materials with water, +filtering the liquid, and evaporating the filtrate to dryness. The +residual mass is taken up with alcohol, and the solution again filtered +and evaporated. Upon dissolving the residue obtained by this operation +in ether and filtering and evaporating the solution, a residue is +obtained which when dissolved in water forms a fluid wherein the +presence of mercury can be detected by means of the ordinary tests. + +When, however, only a minute quantity of mercury is present, and this +has been absorbed, its detection is more difficult. It will be necessary +under these circumstances to make use of either Smithson's pile or +Flandin and Danger's apparatus. + + +SMITHSON'S PILE. + +Smithson's pile consists of a small plate of copper around which a +piece of thin gold foil is wrapped. This is immersed in the solution to +be tested for mercury, which has previously been slightly acidulated: if +mercury be present, the plate acquires a white color which disappears +upon exposure to the flame of a spirit-lamp. A similar reaction occurs +in presence of tin, as this metal would likewise be deposited upon the +plate, and, upon heating, would penetrate the metal and restore to it +its natural color. The danger of mistake arising from this fact is +obviated by introducing the copper plate into a tube closed at one end +and bent at a right angle. The open extremity of the tube is drawn out +to a fine point and immersed in water contained in a second tube also +closed at one end. Upon heating the plate in the flame of an alcohol +lamp, the white color disappears if produced by mercury, and at the same +time this metal condenses in the narrow extremity of the tube. The +metallic globules formed can be recognized either by the naked eye or +with the aid of a lens, or by rubbing them with a piece of gold foil +when the latter will acquire a white coating. + +When Smithson's pile is employed, the organic substances are most +advantageously decomposed by means of chlorine. It is advisable to +operate with as small a quantity of fluid as possible, for, owing to the +volatility of bichloride of mercury, a portion of this salt may be lost +by the evaporation of aqueous, alcoholic, and even etherial solutions, +and the detection of minute quantities rendered impossible. + + +APPARATUS PROPOSED BY FLANDIN AND DANGER. + + [Illustration: Fig. 9.] + +This apparatus consists of a stand _S_, (Fig. 9) supporting a balloon +_A_, which serves as the reservoir of the suspected solution, and a +funnel _B_, into which the neck of the balloon is dipped. The funnel _B_ +is bent at a right angle and is drawn out at its lower end under which +the dish _C_ is placed for the reception of the escaping fluids. A fine +wire of pure gold, forming the negative electrode of a Bunsen's battery, +passes through the lower extremity of the funnel. The end of this wire +nearly comes in contact with a second wire, inserted in the upper part +of the funnel, and connected with the positive pole of the battery. If +the balloon filled with the solution is inverted and immersed in the +funnel _B_, its neck will be submerged at first; soon, however, it +becomes uncovered, owing to the depression of the level of the fluid +caused by the escape of the latter through the tapering extremity of the +funnel: a bubble of air then passes in the balloon and expels a drop of +the solution. This process is repeated at short intervals, causing a +continuous flow of the fluid, the rapidity of which is easily regulated +by elevating or lowering the balloon, thus raising or depressing the +level of the liquid. The apparatus having been mounted in this manner +and the battery set in action, the disengagement of gas commences. +Should mercury be contained in the solution under examination, this +metal will be deposited upon the negative wire. When the operation is +completed this wire is detached from the apparatus, washed with ether, +and dried. It is then introduced into a small tube provided with a bulb, +and the mercury volatilized by means of the blow pipe flame: the metal +condenses in the bulb of the tube in globules which are readily +recognized. They can also be dissolved in nitric acid, and the presence +of a mercurial salt in the solution confirmed by further tests. + +The solution to be examined in the preceding apparatus, is prepared as +follows: + +The suspected organic matter is treated with cold sulphuric acid of 66° +_B._ until liquefied, and hypochlorite of lime, and distilled water then +added: if necessary, the evolution of chlorine can be accelerated by a +further addition of sulphuric acid. As soon as the liquid becomes clear, +it is filtered, concentrated and examined as described above. The +solution contains the mercury in the state of bichloride, a salt soluble +in water and well adapted to the above test. + +The substitution of a large balloon, having a capacity of about 2 +litres, in place of the small vessel of Flandin and Danger's apparatus, +is to be recommended as doing away with the necessity of evaporation; an +operation which invariably causes a loss of substance. The apparatus, +modified in this manner, is the most delicate in use for the detection +of mercury. + + +DETECTION OF PHOSPHORUS. + + +ORFILA'S METHOD. + +The solid substances found in the alimentary canal are mechanically +separated from the fluids present by means of a linen cloth. They are +then examined by aid of a magnifying glass, and any fragments of +phosphorus found separated and preserved under water. If none are +discovered, the presence of phosphorescent vapors may possibly be +detected by examining the materials in the dark. In any case, a portion +of the suspected materials should be treated with nitrate of silver: in +presence of phosphorus the materials acquire, first, a reddish-brown, +then, a black color. The remaining portion is spread upon a shovel and +heated: a white flame, burning at various points of the mass, and +originating from the combustion of phosphorus, is observed, if this body +be contained in the substances under examination. This method is +evidently far from perfect. + + +MITSCHERLICH'S METHOD. + +Mistcherlich's method is based upon the luminosity of the vapors of +phosphorus. The suspected materials are moistened with dilute sulphuric +acid, and heated, in a flask communicating with a glass worm which +passes through a glass cooler into a receiver. If the apparatus is +placed in the dark, and the materials contain phosphorus, luminous +vapors will be observed in the flask and receiver. When the quantity of +the poison present is considerable, the phosphorous acid formed can be +collected and its properties tested. + + +DUSART'S METHOD, AS MODIFIED BY BLONDLOT. + + [Illustration: Fig. 10.] + +Dusart's process takes advantage of the facility with which hydrogen +combines with phosphorus. The substances under examination are placed +between two asbestus stoppers in a tube, one end of which tapers to a +point, and a current of pure hydrogen conducted over them. In presence +of phosphorus the evolved gas will burn with a green flame, and, upon +bringing this in contact with a porcelain plate, red spots will be +deposited upon the latter. _Blondlot_ prefers to introduce the suspected +materials into the flask in which the hydrogen is generated. He employs +the apparatus represented in Fig. 10: _a_ is a flask for evolving +hydrogen; _b_ is a U tube, filled with fragments of pumice stone which +are saturated with a concentrated solution of potassa; _c_ is a Mohr +clamp; _d_ a screw-clamp; _e_ a platinum jet. This jet is necessary in +order to avoid a yellow coloration of the flame by the soda contained in +the glass. Pure hydrogen is at first evolved, in order to ascertain that +the flame is colorless and red spots are not produced when it is +intersected by a cold plate. The purity of the reagents used having thus +been confirmed, the clamp _d_ is closed until the acid is forced back +into _f_; and the materials to be examined are then added to the fluid. +Upon opening the clamp the liquid passes from _f_ into _a_, and the +evolution of gas recommences. The gas is then ignited: the flame +possesses the characteristic properties mentioned above, if the +suspected substances contain phosphorus. + + +METHOD PROPOSED BY FRESENIUS AND NEUBAUER. + +According to this method, the materials are brought into a flask +provided with a doubly-perforated stopper, and water, acidulated with +sulphuric acid, added. The flask is then heated over a water-bath, and a +current of carbonic acid conducted through the mixture for at least two +hours. The gas, on leaving the flask, passes into a solution of nitrate +of silver. Should no precipitate form in this solution, the absence of +free phosphorus is established, for, were this body present, a portion +would be volatilized, and a black precipitate, consisting of phosphide +of silver, together with phosphoric acid, produced. The formation of a +black precipitate is, however, not necessarily a proof of the presence +of phosphorus. In order to conclusively determine the character of the +precipitate, it is collected on a filter and examined by the method of +Dusart and Blondlot. + +This process has given result in cases where none were obtained by +Mistcherlich's method. It possesses, moreover, an advantage over the +latter process, in not being influenced by the presence of foreign +bodies; whereas, in Mistcherlich's method, some time must elapse before +the luminosity of the vapors becomes apparent if ether or alcohol is +contained in the solutions, and this phenomenon totally fails to appear +in presence of oil of turpentine. + + +DETECTION OF PHOSPHORUS BY THE USE OF BISULPHIDE OF CARBON. + +In a report read before the Academy of Sciences in 1856, presented by an +examining commission, of which MM. _Dumas_, _Pelouze_ and _Claude +Bernard_ were the reporters, the following results were contained: +Phosphorus may remain, in the _free state_, in the organs fifteen days +after death, and even then its isolation can easily be accomplished. For +this purpose the stomach or intestines, and the articles of food +contained therein, are cut into pieces and treated with bisulphide of +carbon. Upon filtering the liquid, a solution is obtained containing all +the phosphorus present, which exhibits the following properties: 1st, +When ignited, it burns with a very luminous flame; 2nd, if allowed to +spontaneously evaporate (the combustion of the phosphorus being +prevented by the organic matter present [_Naquet_]) an inflammable +residue is obtained, which, if dissolved in boiling monohydrated nitric +acid, gives a solution that, after saturation with ammonia, produces a +precipitate soluble in acids in solutions of barium salts. If the +solution is mixed with perchloride of iron, and the sesquioxide of this +metal subsequently eliminated by the addition of ammonia, it no longer +causes a precipitation in barium solutions. The fluid acquires a yellow +coloration when boiled with a solution of molybdate of ammonia. + +According to our personal experience, the apparatus employed by Flandin +and Danger for the detection of arsenic, can also be made use of in the +examination of the bisulphide of carbon solution. To this end, the fluid +supposed to contain phosphorus is mixed with perfectly pure alcohol, and +the mixture placed in a small spirit-lamp provided with a very loose +asbestus wick. The lamp is then ignited and the flame introduced in the +combustion tube _D_ (Fig. 11). + + [Illustration: Fig. 11.] + +By the combustion of the mixture, sulphurous, carbonic, phosphorous +acids and water are formed. The water condenses in _c_, and, falling +into the dish _F_, carries with it the sulphurous and phosphorous acids. +The acid liquid collected in this way is evaporated to dryness, some +nitric acid added, and the solution again evaporated. The remaining mass +is then dissolved in water to which some ammonia is added, and the +solution tested for phosphoric acid. This method is an advantageous one +as the phosphoric acid formed must originate from phosphorus in the +_free state_, and not from any phosphates which, owing to the presence +of organic matter, might be contained in the bisulphide of carbon +solution. It would, however, lead the analyst into error if the person, +supposed to have been poisoned had eaten cerebral substances or eggs +previous to death, as these contain glycero-phosphoric acid; it is +therefore advisable to compare the results given by this process with +those obtained by the use of other methods. + + +DETECTION OF PHOSPHOROUS ACID. + +Provided free phosphorus has not been detected, it is necessary to +search for phosphorous acid. To this end, the residue remaining in the +flask, in either Mistcherlich's or Fresenius and Neubauer's method, is +introduced into the apparatus of Dusard and Blondlot. If the phosphorus +reaction appears, it is sufficient; otherwise, its production may have +been hindered by the presence of organic matter. In case, therefore, the +flame is colorless, the evolved gas is conducted into a neutral solution +of nitrate of silver. If the materials contain phosphorous acid, a +precipitate of phosphide of silver is formed which should be collected +and washed. The precipitate, which is now free from organic matter, is +then examined for phosphorous acid by means of the apparatus of Dusard +and Blondlot. + + +ESTIMATION OF PHOSPHORUS. + +The best process for determining quantitatively the amount of +phosphorus present is the one recommended by Fresenius and Neubauer. The +gaseous current is continued until a fresh nitrate of silver solution is +no longer precipitated. The solution is filtered, the precipitate washed +and then dissolved in nitric acid. The silver is next precipitated by +addition of hydrochloric acid, the fluid again filtered, and the +precipitate well washed. The washings are added to the filtrate, and the +liquid concentrated in a porcelain capsule. A solution of sulphate of +magnesia, containing ammonia, is next added to the fluid, and the +phosphoric acid determined as pyrophosphate of magnesia: the precipitate +formed, is washed, heated to redness, in order to convert it into the +pyrophosphate, and then weighed. + + +DETECTION OF ACIDS. + +The search for acids is to be instituted exclusively in the alimentary +canal and its contents. Were acids contained in the other organs, their +presence would be due to the blood in which they had previously been +absorbed, and, as in this case they would be partially neutralized by +the bases contained in the blood, a conclusive decision in regard to +their original existence in the suspected materials would be impossible, +the salts of the acids usually searched for being normal constituents of +the blood. In order to detect the presence of acids, the alimentary +canal and contents are first boiled with water which is renewed until +the solution ceases to exhibit an acid reaction when tested with litmus +paper. The fluid is then filtered, alcohol added to the filtrate, in +order to precipitate organic substances, the liquid again filtered, and +the solution tested separately for the various acids as directed below. + + +HYDROCHLORIC ACID. + +The solution is placed in a retort provided with a receiver and +distilled until the residual fluid assumes a pasty consistence: the +operation is then discontinued. If hydrochloric acid be present in the +materials under examination, the distillate will have an acid reaction, +and, upon addition of solution of nitrate of silver, a white +precipitate, which is easily soluble in ammonia but insoluble in nitric +acid and in short possesses all the properties of chloride of silver, +will be formed. + + +NITRIC ACID. + +The distillate, obtained as in the preceding process, is neutralized by +the addition of potassa or soda, and evaporated to dryness. The residue +is mixed with copper filings, and introduced into a glass tube closed at +one end and provided at the other with a cork through which a +delivery-tube passes. Sulphuric acid is then added to the mixture, the +cork inserted, the tube heated, and the evolved vapors conducted into a +solution of protosulphate of iron. The latter solution acquires a brown +coloration which, upon addition of sulphuric acid, changes to a violet, +if nitric acid be present. Upon conducting the disengaged gas into a +solution of narcotine, the latter acquires a beautiful red color. + +Another portion of the residue should deflagrate when saturated with an +alkali and projected upon live coals. + + +SULPHURIC ACID. + +In order to detect this acid, the solution obtained by treating the +organs with water is not distilled but is concentrated to one-sixth of +its original volume, and then agitated with ether for about ten minutes. +By this treatment the ether takes up the free sulphuric acid, but not +the acid sulphates present. After ten minutes contact, the ether is +decanted and allowed to spontaneously evaporate. Upon treating the +residue, which contains the free sulphuric acid and fatty substances, +with water, a solution containing only the sulphuric acid is obtained. +Nitrate of baryta is then added to a portion of the fluid: in presence +of sulphuric acid, a white precipitate, insoluble in acids, is produced. +If this is heated on charcoal before the blow-pipe, a mass is formed, +which, when moistened with hydrochloric acid and placed upon a clean +silver coin, produces a black spot on the metal. Another portion of the +solution is mixed with copper and the mixture evaporated in a tube +closed at one end: sulphurous acid is evolved towards the end of the +operation. This gas is detected by allowing it to pass over paper +saturated with a mixture of iodic acid and starch; a blue coloration is +produced which, owing to the transformation of the iodine set free into +hydriodic acid, subsequently disappears. (We have never been able to +effect the disengagement of sulphurous acid spoken of above when an +exceedingly dilute sulphuric acid was used, even upon evaporating the +mixture to dryness, notwithstanding Orfila's statement that the reaction +occurs very readily.) + + +PHOSPHORIC ACID. + +The aqueous solution is evaporated to dryness, the residue taken up +with alcohol of 44° B., the fluid again evaporated, and the second +residue dissolved in water. Upon adding acetate of lead to the solution, +a white precipitate is produced if phosphoric acid be present. The +precipitate is washed, suspended in water and a current of sulphuretted +hydrogen passed through the mixture. If the fluid is then filtered, and +the excess of sulphuretted hydrogen expelled from the filtrate by +boiling, a liquid possessing the distinctive properties of a solution of +phosphoric acid will be obtained. This should then be submitted to the +following tests: Some pulverized charcoal is added to a portion of the +solution, the mixture evaporated to dryness, and the residue obtained +introduced into a Hessian crucible heated to redness: in presence of a +considerable amount of the acid, free phosphorous is liberated and burns +with a bright flame in the upper part of the crucible. In case this +reaction fails to occur, other portions of the fluid are treated with a +solution of a baryta salt, which causes a white precipitate, soluble in +nitric acid; with an ammoniated solution of sulphate of magnesia, which +throws down a crystalline white precipitate; and by boiling with +molybdate of ammonia, acidulated with nitric acid, which produces a +yellow precipitation, or at least a yellow coloration of the solution. + + +OXALIC ACID. + +The solution is subjected to the same treatment as in the search for +phosphoric acid, with the exception that, instead of adding acetate of +lead to the fluid obtained by taking up the residue left from the +alcohol with water, it is divided into two portions which are examined +separately. A solution of a lime salt is added to one portion: if oxalic +acid be present, a precipitate, which is insoluble in acetic acid or in +chloride of ammonium, and effervesces when slightly calcined and treated +with hydrochloric acid, is formed. Nitrate of silver is added to the +remaining portion of the solution: the formation of a precipitate, which +detonates when dried and heated in a glass tube closed at one end, is +further evidence of the presence of the acid. + + +ACETIC ACID. + +The solution obtained by treating the alimentary canal with water is +distilled, as in testing for nitric and hydrochloric acids, and the +following properties verified in the distillate: 1st. It has an acid +reaction, and possesses the odor of vinegar; 2nd, unless previously +neutralized with a base, it fails to redden the per-salts of iron; 3rd, +if the distillate is added to a solution of the per-salts mentioned and +sulphuretted hydrogen conducted through the fluid, a black precipitate +is formed; 4th, upon boiling the still acid fluid with a small quantity +of starch, the property of the latter to become colored in presence of +free iodine is not changed; 5th, if heated with an excess of litharge, a +basic salt which restores the blue color to reddened litmus paper is +produced. + + +HYDROCYANIC ACID. + +The detection of hydrocyanic acid requires special precautions. The +substances to be examined are mixed with water, if solids are present, +and introduced into a retort provided with a delivery-tube which dips in +a solution of nitrate of silver. The retort is then heated over a +water-bath. If the evolved vapors produce a precipitate in the silver +solution, the heating is continued until a fresh portion of the latter +is no longer affected. The operation is now interrupted, hydrochloric +acid added to the retort, and heat again applied. Should a second +precipitation of cyanide of silver occur, the presence of a _cyanide_ in +the suspected materials is indicated; whereas the formation of a +precipitate by the simple action of heat would point to the presence of +free hydrocyanic acid or cyanide of ammonium.[H] In case the latter +compound is present, ammonia will be contained in the distillate. + + [H] Ferrocyanides and ferricyanides--non-poisonous + compounds--likewise, evolve hydrocyanic acid when distilled with a + strong acid. Their presence is indicated by stirring a small portion + of the materials with water, filtering the fluid, acidulating the + filtrate with hydrochloric acid, and testing two portions: one with + sesquichloride of iron, the other with protosulphate of iron. If + either of the above salts be present, a blue precipitate is + produced.--_Trans._ + +In order to identify the cyanogen, a portion of the precipitate is +collected upon a small filter, washed, dried, and then allowed to fall +into a rather long tube, closed at one end, in the bottom of which some +iodine has previously been placed. A column of carbonate of soda is then +introduced above the precipitate for the purpose of retaining the excess +of iodine probably taken. Upon heating the lower end of the tube, white +fumes of iodide of cyanogen, which condense in needles upon the cold +portion of the tube, are produced. These are easily recognized by aid of +a magnifying glass. They are colorless and are readily volatilized by +heat. Some ammonia is next added to a solution of protosulphate of iron, +the precipitate formed thoroughly washed, and exposed to the air until +it acquires a greenish hue. The iodide of cyanogen is then withdrawn +from the tube and mixed with potassa-lye and the precipitate mentioned +above. The mixture is evaporated to dryness, the residue obtained +treated with water and the filtered solution then acidulated with +hydrochloric acid. If a solution of a persalt of iron is now added to +the fluid, a blue precipitate is formed. The addition of salts of copper +produces a reddish precipitation. + +The remainder of the precipitate formed in the nitrate of silver +solution is heated with sulphur and then boiled with an aqueous solution +of chloride of sodium: if cyanogen is contained in the precipitate, a +solution of sulphocyanate of soda will be formed, and upon adding +sesquichloride of iron an intense red coloration produced. + +It is evident that the presence of another acid in the solution +examined for hydrocyanic acid would render the detection of _cyanides_ +impossible, but in all cases hydrocyanic acid can be separated without +arriving at a decision in regard to its original state of combination. +Nitric, hydrochloric, and several other acids would not be distilled at +the temperature of the water-bath; an examination for these by the +methods already described can therefore be instituted simultaneously +with the search for hydrocyanic acid. + + +DETECTION OF ALKALIES AND ALKALINE EARTHS. + +The separation of these bodies in the caustic state is a matter of +difficulty owing to the great tendency they possess to become converted +into carbonates; the carbonates of lime, baryta and strontia, moreover, +being non-poisonous in their effects, will not be employed with criminal +intent, and the carbonates of soda and potassa are extensively used as +pharmaceutical preparations. Notwithstanding the small chances of +success, the isolation of the compounds under consideration in the +caustic state is to be attempted. + +To this intent, the organs to be analysed, together with their +contents, are placed in a glass retort provided with a receiver, water +added, and the mixture boiled. The distillate will contain the ammonia +present. When, however, putrefaction has begun, the detection of this +compound does not necessarily indicate its original presence in the +suspected materials. If, after an hour's boiling, the fluid in the +retort possess an alkaline reaction, it is to be examined for soda, +potassa, strontia, baryta and lime. The undistilled solution is +filtered, the filtrate evaporated to dryness, and the residual mass +treated with alcohol. By this treatment, potassa and soda go in +solution, lime, baryta and strontia[I]--as well as the alkaline +carbonates--remaining undissolved. The potassa and soda are separated +from the other salts present by filtering and evaporating the alcoholic +solution to dryness and then calcining the residue in a silver crucible. +The mass, which should still be alkaline, is then dissolved in dilute +sulphuric acid. If the solution is turbid, traces of baryta or strontia +may still be present and should be removed by filtration. Some +hydrochloric acid and solution of bichloride of platinum are then added +to a portion of the filtered liquid: in presence of _potassa_ a yellow +precipitate is formed. + + [I] Baryta and strontia dissolve in alcohol, but only when they are + anhydrous and the alcohol is absolute, which is not the case here. + +Another portion is treated with tartaric acid: a white granular +precipitate is produced. Hydrofluosilicic acid is added to a third +portion of the solution: the formation of a gelatinous precipitate is a +further indication of the presence of potassa. If the preceding tests +have given negative results, and a white precipitate is formed by the +addition of antimonate of potassa to another portion of the solution, +_soda_ is present. In both cases, it is necessary to confirm the results +by means of the spectroscope. + +The above reactions are distinctive only in the absence of metals +precipitated by sulphuretted hydrogen, sulphide of ammonium or carbonate +of soda, and small portions of the solution should be tested with these +reagents. + +In order to detect baryta, strontia and lime, the residue, insoluble in +alcohol is dissolved in dilute nitric acid, and an excess of carbonate +of ammonia added to the solution: the three bases, if present, are +precipitated as carbonates. The precipitate formed is separated from the +solution by filtration, dissolved on the filter in dilute hydrochloric +acid, and the solution then filtered and divided into two parts: +sulphuric acid is added to one, the fluid filtered from the precipitate +of sulphate of baryta formed, and the filtrate treated with ammonia and +oxalate of ammonia. If _lime_ be present,--although its sulphate is not +easily soluble--sufficient will be contained in the filtrate to give a +white precipitate of oxalate of lime. + +The remaining portion of the solution is evaporated to dryness, and the +residue treated with absolute alcohol. Chloride of strontium goes into +solution, chloride of barium remaining undissolved. If upon evaporating +the alcoholic solution a residue is obtained which, when dissolved in +water, produces turbidity in a solution of sulphate of lime, _strontia_ +is present. + +The residue, insoluble in alcohol, is dissolved in water. If a +precipitate is produced by the addition of sulphuric acid or +hydrofluosilicic acid to the solution, _baryta_ is present. The latter +reaction distinguishes baryta from strontia, which is not precipitated +by hydrofluosilicic acid. Should the tests mentioned above fail to give +affirmative results, and poisoning by means of baryta and strontia be +nevertheless suspected, these compounds may possibly have remained in +the materials contained in the alimentary canal, in the state of +insoluble sulphates. To effect their detection under these circumstances +the organic substances must be decomposed by means of sulphuric acid. +The carbonaceous residue is calcined in a crucible at an elevated +temperature, and the remaining mass treated with water. In this way, a +solution of sulphides of barium and strontium is obtained, which is then +tested as directed above. + + +DETECTION OF CHLORINE, BROMINE, AND IODINE. + + +CHLORINE AND BLEACHING CHLORIDES. + +The detection of chlorine is very difficult owing to the great tendency +it possesses to become converted into chlorides or hydrochloric acid, +and it is only when found in a free state that its discovery is of +importance. + +In case the gas exists uncombined in the alimentary canal, its odor +will be perceptible, and, upon boiling the suspected materials with +water, vapors will be evolved which impart a blue color to paper +saturated with a mixture of iodide of potassium and starch paste. If the +addition of sulphuric acid is necessary in order to produce the above +reactions, there is reason to suspect the presence of "chloride of lime" +or "_Eau de Javelle_."[J] + + [J] The so-called "chloride of lime" is probably either a mixture of + chloride and hypochlorite of calcium or an oxydichloride of the metal; + "_Eau de Javelle_" is the corresponding potassium compound.--_Trans._ + + +BROMINE. + +In case bromine exists in a free state at the time the autopsy is made, +its presence will be detected by the reddish color and unpleasant odor +it possesses. Its isolation is accomplished by treating the materials +with bisulphide of carbon which, upon dissolving the bromine, acquires a +red color. If potassa is then added to the solution, it combines with +the bromine and, upon evaporating the decanted fluid, calcining the +residue, and treating it with water, a solution of bromide of potassium +is obtained. Upon adding chlorine-water and ether to a portion of the +fluid, and shaking the mixture, the bromine is liberated and is +dissolved by the ether. The etherial solution of bromine, which +possesses a reddish-yellow color, does not mingle with, but floats upon +the surface of the colorless aqueous solution. + +If nitrate of silver is added to another portion of the aqueous solution +of bromide of potassium, a precipitate of bromide of silver, soluble in +ammonia, is formed. + +In case the bromine has been converted into a bromide, it is necessary +to boil the alimentary canal and the articles of food contained therein +with water. The fluid is next filtered and agitated with chlorine-water +and ether. The liberated bromine is dissolved by the ether, which +acquires a reddish-yellow color. Upon decanting the solution, and +treating it with potassa, bromide of potassium is formed, and can be +detected as directed above. + + +IODINE. + +The detection of iodine is accomplished by a process almost identical +with the above. The isolation of the iodine having been effected, it +remains to be ascertained that it imparts a blue color to starch paste, +and a violet color to bisulphide of carbon. + + +DETECTION OF METALS. + +Under this head we will indicate the systematic course of analysis to be +pursued, supposing a mixture of several metals including arsenic and +antimony, to be under examination. + +The organic substances are first destroyed by means of chlorate of +potassa and hydrochloric acid. When this is accomplished, the excess of +chlorine is removed by boiling and the liquid filtered. The portion +remaining on the filter is preserved: it contains all the silver and a +large portion of the lead, if these metals are present. We will +designate the residue as A, the filtrate as B. + + +TREATMENT OF RESIDUE A. + +The residue is calcined with a little carbonate of soda and cuttings of +pure Swedish filtering paper, the chlorides present being reduced to the +metallic state by this treatment. The residue is next taken up with +water acidulated with nitric acid, and the solution filtered. An +insoluble residue, that may remain, is washed with hot water until the +wash-water ceases to precipitate solution of nitrate of silver, and +dried. It is then dissolved in boiling nitric acid, the solution diluted +with water, and filtered.[K] + + [K] If an insoluble residue remains by the treatment with nitric + acid, it may consist of _tin_. In this case, it is dissolved in _aqua + regia_, the metal precipitated by immersing a plate of zinc in the + solution and then re-dissolved in boiling hydrochloric acid. Upon + adding chloride of gold to the solution so obtained, a purple + precipitate is formed. Sulphuretted hydrogen produces a brown + precipitate, soluble in sulphide of ammonium, in presence of tin. + +Sulphuric acid is added to the filtrate: if no precipitate forms, the +absence of _lead_, in the residue A, is indicated. If, on the contrary, +a precipitate is produced, it is collected upon a filter and washed. In +order to make sure that the precipitate consists of sulphate of lead, it +is treated with a solution of tartrate of ammonia: it should dissolve, +forming a solution in which sulphuretted hydrogen produces a black +precipitate. + +The fluid which has failed to be precipitated by the addition of +sulphuric acid, or the filtrate separated from the precipitate formed, +can contain only silver. Upon adding hydrochloric acid, this metal is +thrown down as a caseous white precipitate, which is soluble in ammonia, +but insoluble in boiling nitric acid, and blackens upon protracted +exposure to light. The formation of a precipitate possessing these +properties, leaves no doubt as to the presence of _silver_. + +_Remark._--In the operations described above, as well as in those +following, the difficulty in separating minute precipitates from the +filter is often experienced. When the precipitate is to be dissolved in +reagents that do not affect the paper, such as ammonia, tartrate of +ammonia, and dilute acids, it can be brought in solution directly on the +filter. In cases, however, where reagents which attack the paper are +employed, the precipitate should be separated. This is accomplished by +mixing a small quantity of pure silica, obtained by the decomposition of +fluoride of silicium by water, with the solution, before filtering. The +precipitate becomes intimately mixed with the silica, and can then be +readily removed from the paper. The presence of silica does not +interfere, it being insoluble in the reagents commonly made use of. + + +TREATMENT OF FILTRATE B. + +A current of sulphuretted hydrogen is conducted for twelve hours through +the solution, which is kept at a temperature of 70°. by means of a +water-bath. The flask containing the liquid is then closed with a piece +of paper, and allowed to remain in a moderately warm place until the +odor of the gas is no longer perceptible. The solution is next filtered +with the precaution mentioned in the preceding remark, and the +precipitate (_a_) thoroughly washed. The water used in this operation is +united to the filtrate, and the fluid (_b_) examined as directed further +on. + + +TREATMENT OF PRECIPITATE _a_. + +In order to free the precipitate from the organic substances possibly +present, at the same time avoiding a loss of any metal, it is dried, +moistened with nitric acid, and the mass heated on a water-bath. Some +Swedish filtering paper is next added, the mixture well impregnated with +sulphuric acid, and then maintained for several hours at a temperature +of about 170°. until a small portion (afterwards returned) gives a +colorless solution when treated with water. The residue is now heated +with a mixture of one part of hydrochloric acid and eight parts of +water, the liquid filtered, the matter remaining undissolved washed with +dilute hydrochloric acid, and the washings united with the filtrate. + +The residue I. and the solution II. are separately examined as directed +below. + + +RESIDUE I. + +This may contain lead, mercury, tin, bismuth and antimony. It is heated +for a considerable time with _aqua regia_, the solution filtered, and +the second residue, should one remain, washed with dilute hydrochloric +acid. If the second residue is fused with cyanide of potassium, the +compounds present are reduced to the metallic state. The liberated +metals are treated with nitric acid, which dissolves _lead_, but leaves +_tin_ as insoluble metastannic acid. The nitrate of lead is then +filtered from the metastannic acid, and both metals are identified as +described in the treatment of residue A. + +The solution, obtained by the action of _aqua regia_ on residue I, is +treated with sulphuretted hydrogen. The tin and antimony are separated +from the lead, mercury and bismuth by treating the precipitate produced +with sulphide of ammonium, which dissolves only the sulphides of the +first two metals. The solution in sulphide of ammonium is afterwards +examined for these metals, as directed under the head of solution IV., +the search for arsenic, however, being here omitted. + +Upon treating the residue insoluble in sulphide of ammonium with nitric +acid, lead, copper and bismuth go into solution, mercury remaining +undissolved. The liquid is filtered, and the undissolved mercury +submitted to the special examination previously described. + +Sulphuric acid is added to the solution and the precipitate of sulphate +of lead formed, separated, washed, and examined as directed while +treating of residue A. + +Finally, the solution separated from the lead is tested for _bismuth_ +and _copper_, as in examination of precipitate III. + + +SOLUTION II. + +The solution is concentrated by heating on a water-bath, a small +quantity of carbonate of soda cautiously added to a portion, and notice +taken if a precipitate forms. The part taken is then acidulated with a +little hydrochloric acid, returned to the principal solution, and +sulphuretted hydrogen conducted through the fluid, as in the examination +of solution B. In case a precipitate fails to form, all metals are +absent; if, on the contrary, a precipitate (_c_) is produced, it is +examined as directed below. + +EXAMINATION OF PRECIPITATE _c_. + +If the solution merely became turbid, or the precipitate formed was of +a pure white color, it consists probably of sulphur. It is, however, +indispensable, even in this case, to collect the precipitate and examine +it for _arsenic_. Provided it is of a pure yellow color, it is treated +with ammonia. In case it is entirely dissolved by this treatment, and +the addition of carbonate of ammonia failed to produce a precipitate in +solution II., it is certain that arsenic, and no other metal, is +present. Under these circumstances, the ammoniacal solution is examined +as directed in the article on the detection of arsenic. If, on the other +hand, the precipitate is not yellow, or being yellow, is but imperfectly +soluble in ammonia, and a precipitate was formed by the addition of +carbonate of ammonia to solution II., it is necessary to likewise search +for tin, antimony, mercury, copper, bismuth and cadmium. In this case, +the precipitate is placed in a small flask, allowed to digest for +several hours with ammonia and sulphide of ammonium in a moderately warm +place, and the solution filtered. + +The remaining residue (III.) is washed, labelled, and preserved for +subsequent examination; the _filtrate_ (IV.) is treated as directed +below. + + +TREATMENT OF SOLUTION IV. + +The solution, to which the water used in washing the residue has been +added, is evaporated to dryness, the residue obtained taken up with pure +fuming nitric acid, and the liquid again evaporated. The second residue +is next saturated with a solution of carbonate of soda. A mixture of 1 +part of carbonate and 2 of nitrate of soda is then added, the mixture +evaporated to dryness, and the residual mass heated to fusion. The fused +mass, when cold, is treated with cold water, and any remaining residue +washed with a mixture of equal parts of alcohol and water. The filtered +fluids are now evaporated in order to remove the alcohol, sulphuric acid +is then added, and the mixture heated until white fumes of the acid +begin to evolve. In this way the complete expulsion of the nitric acid +present is rendered certain. When cold, the residue is treated with +water and the _solution_ introduced into Marsh's apparatus, or, in case +a quantitative estimation of the arsenic is desired, it is treated with +sulphuretted hydrogen and the weight of the precipitate formed +determined, as directed under the detection of arsenic. + +Should a residue insoluble in water remain, it may contain tin, +antimony and traces of copper. Upon dissolving it in _aqua regia_ and +placing a sheet of pure zinc in the solution, these metals are thrown +down in the metallic state. The precipitate is collected, the zinc +present completely removed by treatment with _dilute_ hydrochloric acid, +and the residue boiled with concentrated hydrochloric acid which +dissolves the _tin_ present. The fluid is filtered and the _filtrate_ +tested for this metal by adding solution of chloride of gold, which, in +its presence, produces a purple precipitate, and, by treating it with +sulphurated hydrogen, which forms a brown precipitate, soluble in +sulphide of ammonium. + +If the _residue_, insoluble in concentrated hydrochloric acid, is +thoroughly washed and then treated with nitric acid, the copper present +goes in solution. The fluid is filtered, and ammonia added to the +filtrate: in presence of _copper_, the solution acquires a blue color, +and gives a reddish precipitate upon addition of ferrocyanide of +potassium. + +_Antimony_, if present, remains by the treatment with nitric acid as an +insoluble intermediate oxide. This is dissolved in hydrochloric acid, in +which it is now soluble, and the solution introduced into Marsh's +apparatus. + + +TREATMENT OF PRECIPITATE III. + +This precipitate may contain the sulphides of mercury, copper, cadmium +and bismuth. Upon treating it with nitric acid, all but the sulphide of +mercury are dissolved. In case no residue remains, the absence of +_mercury_ is indicated; if, on the other hand, a residue is left, it is +well washed, dissolved in _aqua regia_, and the solution examined, +either by means of Smithson's pile, or in the apparatus of Flandin and +Danger. (_Vide Detection of Mercury._) + +Whether a residue remains or not, an excess of ammonia is next added to +the filtered solution in nitric acid: the formation of a permanent +precipitate denotes the presence of _bismuth_. In this case, the fluid +is filtered, and the alkaline filtrate further tested for copper and +cadmium. For this purpose, cyanide of potassium is added, and +sulphuretted hydrogen conducted through the filtrate: if _cadmium_ be +present, a yellow precipitate is produced, copper not being thrown down +in presence of an alkaline cyanide. The precipitate of sulphide of +cadmium is separated from the solution by filtration, and the filtrate +saturated with hydrochloric acid. _Copper_, if present, is now +precipitated as sulphide: its separation is completed by conducting +sulphuretted hydrogen through the fluid. + +The precipitate is collected, washed, dissolved in nitric acid, and its +identity established as previously directed. If the metal be present in +sufficient quantity, it should be obtained in a metallic state upon a +plate of iron; it is then coherent, possesses its natural color, and can +conveniently be exhibited to the Jury. + + +TREATMENT OF SOLUTION _b_. + +This solution may contain: cobalt, nickel, iron, manganese, chromium, +zinc and aluminium. Of these, only zinc and chromium are poisonous; the +search for these two metals is therefore all that is necessary in +criminal cases. The solution is treated with a slight excess of ammonia, +sulphide of ammonium added, and the fluid, after being allowed to stand +for several hours, filtered. The precipitate may consist of sulphide of +zinc and hydrated oxide of chromium, as well as of traces of sulphide of +iron and phosphate of lime. If the suspected materials contained a +_chromate_, this salt, in presence of hydrochloric acid and sulphuretted +hydrogen, would be converted into sesquichloride of chromium a compound +which is precipitated by sulphide of ammonium as a hydrated oxide. + +The precipitate is washed with water, to which a little sulphide of +ammonium is added, then dried, and fused with four times its weight of a +mixture of equal parts of carbonate and nitrate of potassa. After the +mass has remained in a state of fusion for a quarter of an hour, it is +treated with boiling water, mixed with a little alcohol, in order to +decompose the manganate that would be present were manganese contained +in the materials under examination. The alcohol is then expelled by +boiling the fluid, and the solution filtered. The _filtrate_ may contain +phosphate of potassa, originating from the phosphate of lime present, +and _chromate of potassa_, resulting from the oxidation of the +sesquioxide of chromium. In presence of the latter compound, the +following reactions will occur in the solution: 1st., Upon acidulation +with acetic acid and addition of solution of acetate of lead, a yellow +precipitate, soluble in potassa, is formed; 2nd., if hydrochloric acid +is added and sulphuretted hydrogen conducted into the solution, the +latter acquires a green color, and, upon adding ammonia, a bluish-grey +precipitate of chromic hydrate is produced; 3rd., if nitrate of silver +is added to the solution, a brick-red precipitate is formed. + +The _precipitate_ remaining on the filter, may consist of zinc, mixed +with the oxides of iron, nickel, cobalt, aluminium and manganese. It is +dissolved in boiling hydrochloric acid, acetate of soda added, and the +fluid boiled until no further precipitation occurs. The iron is now +completely separated. The solution is then filtered, the precipitate +washed, and an excess of potassa added to the _filtrate_; if the +solution contains cobalt, nickel or manganese--which is improbable--a +permanent precipitate is formed. This is separated from the fluid by +filtration: its further examination is, however, unnecessary, as the +metals of which it consists are not poisonous. The _filtrate_ may +contain aluminium and _zinc_. The latter metal is detected by +acidulating the filtrate with acetic acid, and adding a solution of +sulphuretted hydrogen: in presence of zinc a white precipitate of its +sulphide is formed. + +In case organic substances are present, the precipitation of chromium by +sulphide of ammonium may possibly have been hindered, and the metal have +passed into the filtrate. When, therefore, chromium is not detected in +the precipitate, the filtrate should also be examined. For this purpose, +the fluid is evaporated to dryness, and the residue obtained fused with +a mixture of nitrate and carbonate of soda. The fused mass is then taken +up with water, the solution acidulated with acetic acid, and a solution +of acetate of lead added: if chromium be present, a yellow precipitate, +soluble in potassa, is produced. + + +DETECTION OF ALKALOIDS AND SOME ILL-DEFINED ORGANIC SUBSTANCES.[L] + +A general method for effecting the detection of alkaloids was first +proposed by _Stas_. Since the publication of this method, modifications +to it have been recommended by _Otto_, and by _L. Uslar_ and _J. +Erdman_. Other processes have been suggested by _Rodgers_ and _Girwood_, +by _E. Prollius_, and by _Graham_ and _Hofman_. The latter will +doubtless become general in their application; but up to the present +time they have been employed exclusively in the detection of strychnine. +Dialysis has also been recently applied in the separation of alkaloids. + + [L] Colchicine, picrotoxine and digitaline. + + +STAS'S METHOD. + +This method is based upon the facts: (_a_), that the acid salts of the +alkaloids, especially those containing an excess of tartaric or oxalic +acids, are decomposed by caustic alkalies and by the bicarbonates of +soda and potassa; (_b_), that the alkaloids, when liberated in this +manner, are combined with a certain amount of water which determines +their solution in ether, although, in a desiccated state they may be +insoluble in this menstruum; (_c_), that they may be extracted from +their aqueous solutions by agitation with ether. + +Stas's original method is as follows: The suspected substances, if +organs are contained, are cut into fine shreds, then mixed with absolute +alcohol, 0.5 to 2. grammes of tartaric or oxalic acid added and the +whole introduced into a flask and heated at a temperature of 60° to 75°. +When quite cold, the mixture is filtered, and the undissolved portion +remaining on the filter washed with absolute alcohol, the washings being +added to the filtrate. The alcoholic solution is evaporated, either by +placing it under a bell-jar connected with an air-pump, or by passing a +current of air, having a temperature not exceeding 35° over it, until +reduced to a quarter of its original volume: the complete expulsion of +the alcohol being then rendered certain. If insoluble matter separates +during this operation, the concentrated fluid is passed through a +moistened filter, the water used in washing the residue being united to +the filtrate which is then evaporated to dryness by aid of the air-pump +or by placing the fluid in a bell-jar over concentrated sulphuric acid. +When the evaporation is completed, the residue is treated with absolute +alcohol, the alcohol allowed to evaporate at the ordinary temperature of +the air, and the second residue dissolved in the smallest possible +amount of water. The fluid thus obtained is placed in a test-tube, and a +concentrated solution of bicarbonate of soda added so long as +effervescence takes place. Ether is then added, the mixture thoroughly +shaken, and after it has remained at rest for some time, a small portion +of the supernatant ether removed and evaporated on a watch-glass: the +residue obtained will consist of the alkaloid present. Two cases are now +possible: the alkaloid is a solid, or it is a liquid and is volatile. + +The further treatment of the solution is modified according to these +circumstances. + + +_a._ THE ALKALOID IS LIQUID AND VOLATILE. + +If, upon the evaporation of the ether, oily streaks were left on the +watch-glass, a volatile alkaloid is probably present. + +In this case, a solution of caustic potassa is added to the test-tube, +the mixture shaken, the supernatant ether decanted[M] into a flask and +the remaining solution again washed with ether until the last portion +fails to leave a residue upon evaporation. The etherial fluids are then +united, and two cubic centimetres of water, acidulated with one-fifth of +its weight of sulphuric acid, added. This acid retains the alkaloid, +which is now in the state of a pure acid-sulphate soluble in water, the +animal matters present remaining dissolved in the ether. The ether, in +which some sulphate of conia may be contained--although the greater +portion of this compound would remain in the aqueous solution--is then +decanted. The remaining aqueous solution of the pure sulphate of the +alkaloid is placed in a test-tube, a solution of caustic potassa and +some ether added, and the mixture well shaken. The ether is next +decanted and allowed to spontaneously evaporate in a dry place at a very +low temperature, and the ammonia possibly present is then removed by +placing the vessel containing the residue over sulphuric acid. The +residue now obtained consists of the alkaloid present in a state of +purity, and can be directly identified by means of the reactions +described further on. + + [M] The necessity of decanting etherial and other solutions is + advantageously obviated by the use of a pipette.--_Trans._ + + +_b._ THE ALKALOID IS SOLID. + +It sometimes occurs that ether fails to take up all of the alkaloid +present in the fluid treated with bicarbonate of soda. Under these +circumstances the fluid should be mixed with caustic potassa, the +mixture shaken, and the ether decanted; this operation being repeated +several times, until the entire amount of the alkaloid is removed; the +ethereal fluids are then united in a capsule, and allowed to +spontaneously evaporate. The result of the evaporation may be solid; +more frequently, however, a milky liquid remains which restores the blue +color to reddened litmus paper; if so, the presence of a vegetable +alkaloid is certain. In order to purify the residue, a few drops of +water, slightly acidulated with sulphuric acid, are added to the +capsule, and the latter turned, so as to bring the fluid in contact with +the substance at all points; in this manner a colorless and limpid fluid +is obtained, the fatty substances adhering to the dish. The liquid is +decanted into a second capsule, the remaining residue washed with a +little acidulated water, and the washings likewise added to the +principal solution. The fluid is now evaporated either _in vacuo_, or +over sulphuric acid, to about three-fourths of its original volume a +concentrated solution of neutral carbonate of potassa added, and the +mixture treated with absolute alcohol, which dissolves the liberated +alkaloid, and separates it from the sulphate of potassa formed and the +excess of carbonate of potassa. The alcoholic solution is decanted and +allowed to evaporate _in vacuo_ or in the air: the alkaloid now +crystallizes out in a state suitable for further examination. + + +MODIFICATIONS TO STAS'S METHOD, PROPOSED BY OTTO. + +In Stas's method, the loss of morphine is possible, for, if ether is not +added immediately after the addition of carbonate of soda, this alkaloid +crystallizes and is then no longer soluble in that menstruum; and, if +the ethereal solution is not quickly decanted, the portion dissolved +will likewise separate out in small crystals. In both cases, morphine +will remain in the aqueous solution from which the other alkaloids have +been extracted by the ether. _M. Otto_ recommends the addition of +chloride of ammonium and a little soda-lye, in order to dissolve the +alkaloid. Upon allowing the solution so obtained to stand for some time +exposed to the air, crystals of morphine are deposited. + +According to the same authority, it is advisable to omit the distinction +drawn by Stas between volatile and fixed alkaloids, and submit both to +the treatment recommended for those that are volatile. + +Otto also recommends the agitation of the fluid containing the oxalates +or tartrates of the alkaloids with ether, previously to their separation +by means of bicarbonate of soda. By this treatment the elimination of +the coloring matter present--as well as of _colchicine_, _digitaline_, +_picrotoxine_, traces of _atropine_, and various impurities--is +accomplished. As soon as the ether ceases to become colored and to leave +a residue upon evaporation, alkali is added, and the operation concluded +as usual. In this way the alkaloid is obtained, almost directly, in a +pure condition. This last modification appears to us to be a very happy +one, inasmuch as it greatly facilitates the purification of the alkaloid +present. + + +MODIFICATIONS TO STAS'S METHOD, PROPOSED BY USLAR AND ERDMAN. + +1st. The materials to be examined are brought to the consistence of a +thin paste, and digested for about two hours with water, to which some +hydrochloric acid has been added, at a temperature of 60° to 80°. The +mixture is then filtered through a moistened linen cloth, and the +residue washed with warm acidulated water; the washings being added to +the solution. + +2nd. Some pure quartz sand--or, preferably, silica prepared by the +decomposition of fluoride of silicium--is added to the filtrate, the +fluid supersaturated with ammonia, and evaporated to dryness over a +water-bath: the addition of silica renders the residue friable. + +3rd. The residue is boiled repeatedly with amylic alcohol, which +extracts all the alkaloid present as well as the fatty and coloring +matters, and the extracts filtered through filter paper that has been +moistened with amylic alcohol. + +4th. The filtered fluid is thoroughly agitated with ten or twelve times +its volume of almost boiling water acidulated with hydrochloric acid: +the hydrochlorate of the alkaloid present goes into the aqueous +solution, the fatty and coloring substances remaining dissolved in the +oily supernatant layer. The latter is separated by means of a pipette, +and the acid aqueous solution shaken with fresh quantities of amylic +alcohol until completely decolorized. + +5th. The aqueous solution is then concentrated, ammonia added, and the +mixture well shaken with warm amylic alcohol, in which the alkaloid +dissolves. As soon as the solution forms a supernatant layer upon the +surface of the fluid, it is drawn off with a pipette and evaporated on a +water-bath. In this manner, the alkaloid is usually obtained in a +sufficient state of purity to admit of its immediate identification; if, +however, a small portion turns brown when treated with concentrated +sulphuric acid, the process of purification must be repeated. Under +these circumstances it is re-dissolved in dilute hydrochloric acid, the +solution repeatedly shaken with amylic alcohol, in order to extract the +impurities present, and the alkaloid then extracted with ammonia and +amylic alcohol, as previously directed. + +The method of _von Uslar_ and _Erdman_ differs from that of Stas merely +in the substitution of amylic alcohol for ether, and of hydrochloric +acid for oxalic or tartaric acid. It offers no advantages over Stas's +method if the alkaloids present are soluble in ether but is even less +advantageous in this case, inasmuch as its execution requires a longer +time. In cases where the detection of morphine, or an unknown alkaloid, +is desired, the use of amylic alcohol instead of ether is, it is true, +preferable; still, with the exercise of care, ether can also be +employed, and, as this process greatly facilitates examinations when no +clew to the poison present exists and all alkaloids may possibly be +absent, we prefer it to the one just described. + + +RODGERS AND GIRDWOOD'S METHOD. + +This method--which as yet has only been employed in the detection of +strychnine--is based upon the solubility of this alkaloid in chloroform. +The substances under examination are digested with dilute hydrochloric +acid, and the mixture filtered. The filtrate is then evaporated to +dryness on the water-bath, the residue taken up with pure alcohol, the +alcoholic solution evaporated, the second residue treated with water, +and the solution so obtained filtered. The filtrate is next +supersaturated with ammonia, and well shaken with chloroform, which, +upon being separated by means of a pipette and evaporated, leaves the +alkaloid in an impure state. Concentrated sulphuric acid is then poured +upon the alkaloid: the latter is not affected by this treatment, whereas +the foreign organic substances present are carbonized. After the lapse +of several hours, the mixture is treated with water, the fluid filtered, +and the strychnine extracted from the filtrate by means of ammonia and +chloroform, as already described. The operation is repeated until the +residue obtained by evaporating the chloroform is no longer affected by +the treatment with sulphuric acid. + + +PROLLIUS'S METHOD. + +The suspected substances are boiled with aqueous alcohol, mixed with +tartaric acid, and evaporated at a gentle heat. The remaining aqueous +solution is then passed through a moistened filter, ammonia added to the +filtrate, and the mixture shaken with chloroform. The chloroform is +separated, the last trace of the original solution removed by washing +with water, three parts of alcohol added, and the fluid evaporated. If +strychnine be present, it will now separate out in crystals. This method +is applicable only in presence of a considerable quantity of strychnine, +and is less serviceable than the one preceding. + + +GRAHAM AND HOFMAN'S METHOD. + +This method, which is applied to the detection of strychnine in beer, is +founded upon the fact that an aqueous solution of a strychnine salt +yields the alkaloid to animal charcoal, from which it can be +subsequently extracted by boiling with alcohol. The beer to be examined +is shaken with 30 grammes of animal charcoal, and the mixture then +allowed to stand twenty-four hours, with occasional shaking. The +solution is next filtered, the animal charcoal washed with water, and +boiled for half-an-hour with four times its weight of 90 per cent. +alcohol. The apparatus represented in Fig. 12 is employed, in order to +avoid a loss of substance in this operation. + + [Illustration: Fig. 12.] + +The alcohol is filtered hot, evaporated, and the residue obtained +treated with a small quantity of solution of potassa, and then agitated +with ether. Upon spontaneous evaporation, the ethereal solution leaves +the strychnine present in a comparatively pure state. + +_Macadam_ proposes to use this process for the detection of strychnine +in animal bodies. For this purpose, the suspected materials are heated +with a solution of oxalic acid, as in Stas's method, and the strychnine +detected in the filtered solution in the manner just described. This +method is scarcely to be recommended: the use of animal charcoal is +doubtless serviceable in the examination of beer, as it effects the +separation of a small amount of strychnine from a large quantity of +fluid, but its application to other researches is much less to be +advised. + + +APPLICATION OF DIALYSIS IN THE DETECTION OF ALKALOIDS. + +In order to apply the dialytic method to the separation of alkaloids, +the suspected substances are heated with hydrochloric acid, and the +solution introduced into the dialyzer. The hydrochlorates of the +alkaloids, being crystalline bodies, transverse the membrane, and are +contained, for the greater part, after twenty-four hours, in the outer +solution. The fluid is then concentrated, and the alkaloids either +directly precipitated, or purified by one of the preceding methods. + + +IDENTIFICATION OF THE ALKALOID. + +The alkaloid having been isolated by one of the preceding methods, it +remains to establish its identity. Owing to the small number of +reactions characteristic of organic compounds, this is a matter of +considerable difficulty. There are two cases possible: the alkaloid may +either be volatile or fixed. + + +THE ALKALOID IS VOLATILE. + +In this case it may consist of nicotine, conine or aniline: less known +alkaloids (piccoline, etc.) may also be present. We will confine +ourselves to the consideration of the three first mentioned. + +The alkaloid is divided into several portions which are placed on +watch-glasses and submitted to the following tests: + +_a._ A drop is treated with nitric acid: this may, or +may not, impart a red tint to the alkaloid; if it +does, another drop is treated with dry hydrochloric +acid gas: if it assumes a deep violet color, it +probably consists of _conine_. + +_b._ In case a red color was not produced by the +addition of nitric acid, another drop is treated with +chloride of lime. If it acquires a violet tint, and +two other drops, when heated, one with arsenic acid, +the other with nitrate of mercury, become red, the +body present consists of _aniline_. +or an homologous base. + +_c._ Should the above tests fail to give positive +results, and the substance, when treated with +chlorine, assumes a blood-red color, and with +hydrochloric acid does not change in the cold but +turns to a deep violet color upon boiling, it probably +consists of _nicotine_. + + +THE ALKALOID IS FIXED. + +A very minute quantity is dissolved in the smallest possible amount of +hydrochloric acid, and an excess of ammonia added. Three cases are now +possible: (_a_) A precipitate, insoluble in an excess of the +precipitant, is immediately formed; (_b_) a precipitate is formed, +which, at first dissolves, but is subsequently deposited from the fluid; +(_c_) no precipitate is produced, or, in case one forms, it dissolves in +an excess of the precipitant and fails to separate out upon allowing the +fluid to stand. + + +_a. Ammonia produces a permanent precipitate._ + +A small quantity of an aqueous solution of carbonic acid is poured over +the alkaloid in the water-glass, and notice taken whether it dissolves +or not: in either case the mixture is evaporated on a water-bath to +dryness, in order to avoid a loss of substance. + + +CARBONIC ACID FAILS TO DISSOLVE THE ALKALOID. + +After the evaporation is completed, ether is added to the watch-glass: +the alkaloid may, or may not, be dissolved. The ether is then evaporated +at the ordinary temperature of the air. + +_Ether fails to dissolve the alkaloid._ + +It probably consists of _berberine_. + +In this case, it will possess a yellow color, and its +hydrochlorate will give a reddish-brown precipitate +upon addition of sulphide of ammonia. + +_Ether dissolves the alkaloid._--A small portion is +treated with nitric acid. If an intense green +coloration is produced, the remaining portion is +dissolved in ether, and an ethereal solution of oxalic +acid added. If the precipitate now formed does not +dissolve upon the addition of a little water, there is +reason to suppose the presence of _aricine_. + +Provided the addition of nitric acid did not produce a +coloration, the mixture of the alkaloid and this acid +is treated with a small quantity of sulphuric acid: if +the fluid now acquires a red color, the substance +probably consists of _narcotine_. + +Should both nitric and sulphuric acids fail to cause a +reaction, the alkaloid is dissolved in ether, +precipitated by an ethereal solution of oxalic acid, +and the precipitate treated with a little water. If it +dissolves, it probably consists of _papaverine_. + + +CARBONIC ACID DISSOLVES THE ALKALOID. + +The substance is treated with ether, notice being taken if it dissolves, +which is evaporated at the ordinary temperature of the air so as to +prevent a loss of minute portions of the alkaloid. + +_Ether dissolves the alkaloid._--If nitric acid gives +first a scarlet, then a yellow color, sulphuric acid a +yellow, changing to red and violet, and hydrochloric +acid a violet color, the alkaloid present is probably + _veratrine_. + +If the above colorations are not produced, chlorine +water is added to another portion of the substance, +then ammonia; the formation of a green color, changing +to violet and turning red upon a renewed addition of +chlorine water, denotes the presence of _quinine_. + +In case all of these tests give but negative results, +and the alkaloid is soluble in concentrated sulphuric +acid, a solution being formed which assumes a +reddish-violet tint when stirred with a glass rod +previously dipped in bromine water, the presence of + _delphine_. +is indicated. + +_Ether fails to dissolve the alkaloid._--If the +substance is capable of being sublimed,[N] it consists +of _cinchonine_. + + [N] Cinchonine, when sublimed, condenses in minute brilliant + needles.--_Trans._ + + +_b. Ammonia produces a precipitate, which redissolves in an excess of +the precipitant, but separates out after the lapse of an hour._ + +The substance is treated with cold absolute alcohol +and its solubility in this menstruum noted. If it +readily dissolves, it probably consists of _brucine_. + +The presence of this alkaloid is confirmed by applying +the following tests: (1) Nitric acid imparts a +blood-red color to the substance; (2) if treated with +sulphuric acid, it acquires a reddish tint which +subsequently changes to yellow and green; (3) chlorine +at first fails to cause a coloration, but after some +time a yellow color which afterwards changes to a red +is produced; (4) upon treating the substance with +bromine, it immediately assumes a violet tinge. + +In case the alkaloid is only slightly soluble in +alcohol, there is reason to infer the presence of + _strychnine_. + +The following confirmatory tests should be applied: +(1) If the substance is treated with a mixture of +sulphuric acid and an oxidizing body, such as +bichromate of potassa, binoxide of manganese, or +peroxide of lead it acquires a violet color, which +changes into red and finally passes into a clear +yellow; (2) the addition of bichloride of platinum +produces a precipitation of the hydrochlorate. + +Should, however, the substance be only slightly soluble +in alcohol, and the above reactions fail to take place, +the presence of _solanine_. +is indicated. In presence of this alkaloid the following +reactions will occur: (1) Upon treating the substance +with concentrated sulphuric acid, it assumes a rose +tint, which changes after some time has elapsed first to +a deep violet, then to a brown color; (2) a solution of +a salt of the alkaloid reduces gold and silver salts; +(3) the addition of oxalic acid produces a precipitate +in the aqueous and even acid solution of its salts. + + +_c. Ammonia fails to produce a precipitate, or redissolves permanently +the one formed._ + +The solubility of the alkaloid in ether is ascertained. If it be +soluble, it may consist of aconitine, atropine or codeine; if insoluble, +of emetine or morphine. + +_The alkaloid is soluble in ether._--If bichloride of +platinum fails to precipitate the hydrochlorate from a +neutral solution of the alkaloid, and sulphuric acid +causes it to assume a yellow color which subsequently +changes to a reddish-violet, it probably consists of + _aconitine_. + +In case bichloride of platinum causes a precipitate +and sulphuric acid fails to produce the yellow +coloration referred to above, the presence of either +atropine or codeine is indicated. In order to decide +which of these bases is present, the substance is +dissolved in pure chloric acid and the solution allowed +to spontaneously evaporate. If the alkaloid is +deposited during this operation, it probably consists +of _atropine_. + +If this is not the case, there is reason to infer the +presence of _codeine_. + +_The alkaloid is insoluble in ether._--If it dissolves +in acetone it probably consists of _emetine_. + +If acetone fails to dissolve it, the presence of + _morphine_. +is indicated. + +The following confirmatory tests should be applied: (1) +Upon treating the substance with nitric acid, it +acquires a blood-red color; (2) the addition of a +solution of a persalt of iron produces an evanescent +blue coloration; (3) chloride of gold is colored blue, +when treated with the alkaloid; (4) the substance +reduces iodic acid: this reduction is detected by +adding to the acid a little starch-paste, which turns +blue upon the liberation of the iodine; (5) +permanganate of potassa, if heated with the substance, +is reduced and acquires a green color. + + +IDENTIFICATION OF DIGITALINE, PICROTOXINE AND COLCHICINE. + +It has already been remarked that in exhausting the first acid solution +with ether--previous to the neutralization, according to Otto's +method--colchicine, a weak alkaloid, digitaline, an indefinite mixture, +picrotoxine (which appears to possess the properties of an acid), and +traces of atropine, pass into solution. + +The ether is evaporated on a water-bath to dryness, the residuary mass +treated with slightly warmed water and the solution filtered from the +undissolved resinous matter. The aqueous solution is next rendered +feebly alkaline by addition of soda lye, and then well agitated with +ether, until this fluid ceases to leave a residue upon evaporation. The +ethereal solution is now decanted, and the water present removed by +means of chloride of calcium. If it is evaporated, a residue containing +the _colchicine_, _digitaline_ and traces of atropine (mixed possibly +with a minute quantity of picrotoxine, which is here left out of +consideration) is obtained. + +_a._ The _alkaline solution_, from which the ether has been removed, is +acidulated with hydrochloric acid and again shaken with ether. The +_picrotoxine_ present is now dissolved, and upon dehydrating (by means +of fused chloride of sodium) and evaporating the ethereal solution can +be obtained in crystals. The crystals of picrotoxine are easily +recognized by their forming in feathery tufts as well as by their length +and silky brilliancy. Should crystals fail to form in a short time, it +is advisable to take up the residue, left by the evaporations of the +ether, with slightly warmed alcohol, and to allow the latter to +spontaneously evaporate on a watch-glass, or, if the quantity of +substance is exceedingly minute, on the slide of a microscope. After +determining the form of the crystals, it should be ascertained that they +possess an intense bitter taste and exhibit the other characteristic +properties of picrotoxine. The following reaction is distinctive: If the +crystals are dissolved in an aqueous solution of soda and a few drops of +"Fehling's solution"[O] added, a reddish precipitate of cuprous oxide is +formed. + + [O] An alkaline solution of tartrate of copper, employed in the + examination of sugar, urine, and wine.--_Trans._ + +_b._ Provided picrotoxine has not been found, the _ethereal solution_ +obtained by agitating the alkaline fluid with ether is to be examined +for colchicine and digitaline. To this end, the residue obtained upon +evaporating the solution to dryness is taken up with water, and the +filtered fluid tested as follows: 1. It is ascertained if a drop of the +solution possesses the bitter taste of digitaline. 2. Another drop is +treated with solution of tannin; if either alkaloid be present, a +precipitate is formed. 3. Two drops of the solution are next tested: one +with tincture of iodine, the other with chloride of gold. These reagents +precipitate colchicine, but do not affect solutions of digitaline or +picrotoxine. Unfortunately traces of atropine, possibly present, would +cause the same reaction; the test therefore fails to be conclusive. 4. +Several portions of the solution are evaporated on watch crystals. +Concentrated nitric acid is added to one portion: if colchicine be +present, an evanescent violet coloration is produced, which changes to a +light yellow upon addition of water, and to a pure yellow or +reddish-orange color, if the mixture is saturated with a slight excess +of caustic alkali. 5. Another portion of the residue is dissolved in a +few drops of concentrated sulphuric acid, and the solution stirred with +a glass rod moistened with bromine water: in presence of digitaline a +violet-red color is produced. This coloration is more distinct when a +small quantity of the alkaloid and an excess of sulphuric acid are +present. 6. If a large amount of substance is at hand, the residue can +be boiled with hydrochloric acid, and the green or brownish color and +characteristic odor of digitaline produced, in case this body be +present: this, however, is not a very delicate test. 7. Finally; it is +advisable when the presence of digitaline is suspected to ascertain its +physiological action. For this purpose, a minute quantity of the +substance is placed upon the heart of a frog: in presence of the +alkaloid, the pulsations are immediately retarded, or even arrested. + + * * * * * + +Although by means of the tests given above the existence of a special +alkaloid, or of one of the ill-defined substances just mentioned, may be +justly regarded as probable, its presence has not yet with certainty +been demonstrated. This is especially true in cases where the compound +possesses but few characteristic properties. When possible, the +suspected substance should be obtained in a crystaline form, and then +compared by aid of the microscope--if the small quantity present permits +of no other examination--with crystals of the pure alkaloid, prepared +under the same conditions. + +In case 20 or even 10 centigrammes of substance are at hand, it is +best to convert the alkaloid into its hydrochlorate, and evaporate the +solution of this salt to dryness. The residue, after being weighed, is +dissolved in water, and a solution of sulphate of silver added. The +precipitate of chloride of silver formed is collected and carefully +weighed, in order to calculate the weight of the chlorine contained in +the hydrochlorate and consequently the molecular weight of the alkaloid. +The filtrate from the chloride of silver, which contains the alkaloid in +the state of sulphate, is treated with hydrochloric acid, to remove the +excess of silver present and the fluid then filtered. The filtrate is +next shaken with potassa and ether. Upon decanting and evaporating the +ethereal solution, a residue consisting of the alkaloid present is +obtained, which is then purified by crystallization from alcohol. An +elementary analysis of the alkaloid is now executed. _Certainty_ as to +the presence of an individual alkaloid is attainable only when the +execution of this confirmatory test is possible. The reactions +previously described can be performed with fifteen centigrammes of +substance, and this amount is sometimes contained in a cadaver. If but +one or two centigrammes are at hand, it is still possible to detect the +presence of an alkaloid; a conclusion, however, as to _which_ cannot be +arrived at, especially if the substance found is a liquid or an +amorphous body, and one that presents few distinctive properties. + + + + +III. + +METHODS TO BE EMPLOYED, WHEN NO CLEW TO THE NATURE OF THE POISON PRESENT +CAN BE OBTAINED. + + +If poisoning has been caused by the administration of a mixture of +numerous substances and these greatly differ in their properties, it is +impossible to demonstrate in an incontestible manner the presence of +each individual poison. This contingency fortunately but seldom arises; +the criminal usually has recourse to one or two poisons, the detection +of which is possible. It must not be imagined, however, that the +presence of a poison in an organ can at once be detected with certainty +by the mere application of a few tests; because, in searching for a +substance which is absent, we may unwittingly destroy the one present, +or, at least, transform it into combinations which would not allow of a +definite conclusion as to its original condition. + +In order to follow a systematic method in researches of this nature, it +is advisable to divide the materials under examination into three parts: +one portion is preserved, in order to ascertain its physiological +effects on animals, the chemical analysis having failed to give positive +results. The other portions are submitted to analysis, but with slightly +different objects in view; one is subjected to a series of tests which +are adapted, under all circumstances, to place the chemist on the track +of the poison present, and which, in some cases, may even give +conclusive and definite results. Should these tests furnish only +_indications_ of the nature of the poison, the remaining portion serves, +with the assistance of this information, to establish beyond doubt the +identity of the substance. + + +INDICATIVE TESTS. + +Two cases may present themselves: the materials to be examined possess +either an alkaline (or neutral) or an acid reaction. As the methods to +be pursued in either of these cases differ somewhat, they will be +treated separately. + + +THE SUBSTANCE POSSESSES AN ACID REACTION. + +The materials are mixed with water, placed in a retort provided with a +delivery-tube which dips in a solution of nitrate of silver, and heated +over a water-bath: if a _cyanide_ be present, hydrocyanic acid will be +disengaged, and a white precipitate of cyanide of silver formed: this is +examined as previously directed (_vide_ p. 50). + +In case a precipitate is not produced by the above treatment, more +water is added to the retort, and the mixture boiled for about an hour, +care being taken to collect the evolved vapors in a well-cooled +receiver. The portion remaining in the retort is thrown on a filter and +the filtrate obtained united with the distillate. The residue remaining +on the filter is next washed with boiling absolute alcohol, the washings +being added to the aqueous solution. In this way, the suspected +substances are divided into soluble and insoluble portions, which are +examined separately, as directed below. + + +_a._ LIQUID PORTION. + +If the addition of alcohol caused a precipitation of animal matters, +these are separated by filtering the solution. The filtrate is then +placed under a bell-jar over concentrated sulphuric acid until its +volume is considerably reduced. The solution may contain organic and +inorganic bases and acids. In order to detect all bodies that are +present, the following course is pursued: + +(1). A current of sulphuretted hydrogen is conducted through the +solution: the precipitation of some metals, usually thrown down by this +gas, may fail to take place in this instance, owing to the presence of +organic substances; however, some metals are precipitated, even in +presence of organic compounds, and organic acids are but seldom present. +In case a precipitate is formed, it is mixed with pure silica, collected +on a filter, and treated with nitric acid. If the precipitate fails to +dissolve, it is treated with _aqua regia_. In either case, the solution +obtained is examined for metals by the ordinary methods. + +(2). The solution in which sulphuretted hydrogen failed to produce a +precipitate, or the filtrate separated from the precipitate formed, is +divided into two parts: one portion is treated with ether and a solution +of potassa; the other with ether and a solution of soda. Both mixtures +are then well agitated, and notice taken if the ether dissolves any +thing: if so, the operation is repeated several times until all soluble +substances are removed. The ethereal solutions are next decanted and +united, and then submitted to the examination for alkaloids as directed +pp. 65-84. + +(3). If--the above treatment giving either positive or negative +results--a precipitate insoluble in ether is formed by the addition of +potassa or soda, it is collected on a filter, washed, and dissolved in +an acid. The solution is then tested for mineral bases. + +(4). In case no definite result has been obtained by the preceding +operations, one of the portions (for instance, the one to which potassa +was added) is tested for the acids possibly present in the state of +salts. The solution is divided into two parts (A and B) which are +examined separately: + +PORTION A.--This is evaporated to dryness and the residue divided into +four parts which are then tested for hydrofluoric, nitric, oxalic, and +acetic and formic acids. + +_a._ HYDROFLUORIC ACID.--A portion of the residue is heated in a +platinum crucible with sulphuric acid, and the crucible covered with the +convex face of a watch-crystal coated with wax in which lines have been +traced with a pointed piece of wood. If, after gently heating the +crucible for some time and removing the watch-crystal, the lines traced +in the wax are found to be etched in the glass, the substance under +examination contains a _fluoride_. + +_b._ NITRIC ACID.--If this acid be present, and a second portion of the +residue is heated with sulphuric acid and copper, reddish-fumes are +evolved. Upon conducting the vapors into a solution of sulphate of iron +or narcotine, the reactions already mentioned in treating of nitric acid +take place. + +_c._ OXALIC ACID.--The third portion of the residue is heated with +sulphuric acid, and the evolved gas carefully collected. It should then +be confirmed by an elementary analysis that the gas consists of equal +volumes of carbonic oxide and carbonic acid. This test is not +conclusive; it is also necessary to ascertain if the precipitate +produced by the addition of a baryta solution (_vide_: under portion +_B._) produces the same reaction, inasmuch as other organic bodies could +give rise to carbonic oxide and carbonic acid, and the danger of both +admitting the presence of oxalic acid, when it is absent, and omitting +its detection, in case it is present, would be incurred. + +_d._ ACETIC AND FORMIC ACIDS.--The fourth portion of the residue is +distilled with dilute sulphuric acid. After determining that a small +portion, previously neutralized with a base, acquires a red color, upon +addition of a solution of a persalt of iron, the distillate is divided +into two parts. One portion is treated with bichloride of mercury: if +_formic acid_ be present, metallic mercury is formed, with evolution of +carbonic acid which produces turbidity in lime-water. The remaining +portion of the fluid is digested, in the cold, with an excess of +litharge: in presence of _acetic acid_, a soluble basic salt of lead, +possessing an alkaline reaction, is produced. + +PORTION B.--The second portion of the solution is supersaturated with +nitric acid, and this neutralized by addition of a slight excess of +ammonia. The ammonia is then expelled by boiling the fluid, and a +solution of nitrate of baryta added. If a _precipitate_ forms, it is +collected and subsequently examined for sulphuric, phosphoric, oxalic +and boric acids as directed below. The _filtrate_ is preserved and +tested for hydrochloric, hydrobromic and hydriodic acids. + +_a._ OXALIC ACID.--A portion of the precipitate produced by the addition +of nitrate of baryta is submitted to the test mentioned under the +treatment of portion _A_. + +_b._ SULPHURIC ACID.--If an insoluble residue remains upon treating the +remainder of the precipitate with dilute hydrochloric acid, it consists +of sulphate of baryta and indicates the presence of _sulphuric acid_. + +_c._ PHOSPHORIC ACID.--An excess of solution of alum and ammonia is +added to the portion of the precipitate dissolved in hydrochloric acid. +If phosphoric acid be present, insoluble phosphate of alumina is +precipitated. This is brought upon a filter: the _filtrate_ being +preserved and subsequently examined for boric acid. Upon boiling the +precipitate with solution of silicate of potassa, silicate of alumina is +thrown down, and phosphate of potassa remains in solution. Chloride of +ammonia is now added to the liquid--in order to eliminate the excess of +silica from the silicate--and the solution filtered. The _filtrate_ is +then tested for phosphates, by means of molybdate of ammonia (_vide_: +_detection of phosphoric acid_, p. 48). + +_d._ BORIC ACID.--The filtrate from the precipitate of phosphate of +alumina is evaporated to dryness, the residue mixed with sulphuric acid +and alcohol, and the latter ignited. If the substance contains _boric +acid_, the alcohol will burn with a _green_ flame. + +The _filtrate_, separated from the precipitate produced by the addition +of nitrate of baryta, may contain hydrochloric, hydrobromic and +hydriodic acids. In order to detect these compounds, some nitrate of +silver is added to the solution, and the precipitate that may form +carefully washed and decomposed by fusion with potassa. The mass is then +dissolved in water, and the solution submitted to the following tests: + +_e._ HYDRIODIC ACID.--Some starch paste and nitric acid--containing +nitrous acid in solution--are added to a portion of the solution: in +presence of an _iodide_, the fluid immediately acquires a blue color. + +_f._ HYDROBROMIC ACID.--In case iodine has not been detected, chlorine +water and ether are added to a second portion of the fluid, and the +mixture well agitated. If _bromine_ be present, the ether will assume a +_brown_ color. In case iodine is also contained in the fluid, and the +detection of bromine is desired, it is necessary to acidulate the +solution with hydrochloric acid, and then shake it with chloride of lime +and bisulphide of carbon. The bisulphide of carbon dissolves the iodine, +acquiring a _violet_ color, which disappears upon a renewed addition of +chloride of lime; whereas, in presence of bromine an _orange_ coloration +remains, even after the disappearance of the iodine reaction. + +_g._ HYDROCHLORIC ACID.--Since the substance under examination will +already contain hydrochloric acid, it is unnecessary, in most cases, to +institute a search for this compound. Nevertheless, it may be well to +take a quantity of the solution, corresponding to a known weight of the +original substance, and precipitate the acid by adding nitrate of +silver. The precipitate formed is dried and weighed. It is then heated +in a current of chlorine, in order to completely convert it into +chloride of silver, and its weight again determined. Only in case the +amount of chloride found is very large, is it to be inferred that the +poisoning has been caused by hydrochloric acid. + +_h._ HYDROSULPHURIC ACID.--(_Sulphuretted hydrogen_). If the precipitate +produced by nitrate of silver possesses a black color, it may consist of +a _sulphide_. Upon treating a portion with solution of hyposulphite of +soda, all but the sulphide of silver is dissolved. In case a residue +remains, it is calcined with nitrate of soda, and the sulphate formed +detected by adding a soluble barium salt to its solution. + +Sulphates, chlorides, carbonates and phosphates are most frequently met +with in the preceding examination, and it should be carefully noticed +which of these salts exist in the greatest abundance. If acids of +comparatively rare occurrence (such as the oxalic and tartaric) are +found, their approximate amount is also to be noted. These facts, +together with the original acidity of the materials and the absence of +other toxical bodies, would lead to the conclusion that the poisoning +was caused by the reception of an acid, as well as to the identification +of the special acid used. In subsequently effecting the detection of the +poison by the determinative tests, the danger of destroying other +poisons possibly contained in the substance will be obviated, as the +question of the absence or presence of these latter will have been +previously decided. + +(5). The examination for acids concluded, the various fluids which have +accumulated, and from which the acids present have been separated, are +united and the whole evaporated to dryness. The organic substances, +present in the residue obtained, are destroyed by means of nitric acid, +and the residual mass examined for _soda_. If this substance has not +been introduced into the portion of fluid examined, and is discovered in +a quantity largely in excess of the amount normally contained in the +organism, it is probable that poisoning has been caused by its +administration, and that an acid has also been given, either in order to +mask the poison, or to act as an antidote. In this case, it is necessary +to carefully search for acetic acid, as this is the substance usually +employed as an antidote for alkalies. + +(6.) Whatever results have been obtained by the preceding examinations, +the portion of the fluid which has been treated with soda (_vide_ p. +87) is evaporated to dryness. The organic matters possibly present +are destroyed by means of nitric acid, or _aqua regia_, and the residue +taken up with water. The solution so obtained is then examined for +metals (including potassa, which salt has not been introduced into this +portion of the fluid in any of the preceding operations) by the usual +methods. + +(7). The soluble portion of the suspected materials having been +thoroughly tested, the undissolved substances remaining on the filter +are next examined. + + +_b._ SOLID PORTION. + +(1). The organic matter present is first destroyed by treatment with +_aqua regia_. The fluid is then evaporated to dryness, and the residue +heated until the nitric acid is entirely expelled; the escaping vapors +being collected in a cold receiver. The residue is next taken up with +water, the solution filtered, and sulphuric acid added. Should a +precipitate of sulphate of lime, sulphate of baryta or sulphate of +strontia form, it is separated from the fluid and further examined. The +filtered solution is then introduced into Marsh's apparatus, sodium +amalgam being employed for generating the hydrogen, and tested for +_arsenic_ and _antimony_ by means of the reactions previously given. + +(2). Whether one of the above poisons be discovered or not, the still +acid fluid is removed from the flask, a current of chlorine conducted +through it for several hours and the solution then examined for +_mercury_ by Flandin and Danger's method. In case mercury is found it +could scarcely have originated from the metal in Marsh's apparatus, as +this would not be attacked by cold dilute sulphuric acid: however, to +remove all doubts, the test should be repeated with a portion of the +substances reserved for the examination by the determinative tests. + +(3). Whatever have been the results of the above examinations, it is +still to be ascertained if the fluid, which has been successively +treated by Marsh's and Flandin and Danger's methods, does not contain +other metals. This is accomplished by means of the ordinary reactions. + + +THE SUBSTANCE POSSESSES A NEUTRAL OR AN ALKALINE REACTION. + +The examination is conducted in precisely the same manner as in the +preceding case, excepting that the materials are first acidulated with +oxalic or tartaric acids. Particular attention should be given to the +search for soda, potassa, lime, baryta and strontia, and the +determinative tests subsequently applied according to the indications +obtained. + + +DETERMINATIVE TESTS. + +In many instances the tests we have termed indicative become +determinative in their character. This is the case when the isolation of +an alkaloid or a metal (unless mercury be found under the circumstances +already mentioned) is accomplished; the results obtained are then +_conclusive_. If, on the other hand,--not being able to separate either +an alkaloid or a metal--upon saturating the originally acid fluid with +potassa, or soda, the salts of these bases have been found in abundance, +there is reason to _infer_ that the poisoning has been caused by an +acid; or, if, after the neutralization of the originally alkaline +solution with an acid, potassa or soda are discovered in a large +quantity, poisoning by an alkali is _indicated_. + +In case the fluid is neutral, but more or less colored and odoriferous, +and iodides or bromides are detected, we may justly _suspect_ that the +poisoning has been caused by the reception of iodine or bromine. + +According to the indications furnished, iodine, bromine, one, or all of +the acids, the caustic alkalies, etc., are then detected by means of the +methods to be employed in cases where the expert has a clew to the +poison present. In this manner, the presence of potassa and soda, and of +bromine and iodine, even in mixtures, is easily ascertained. It only +remains to mention the course to be pursued when suspicion exists that +poisoning has been caused by the administration of a mixture of several +acids. The suspected materials are boiled with water, and alcohol added +to the solution in order to coagulate the animal matters. The solution +is next filtered, the filtrate placed in a retort provided with a +receiver and distilled until the residual portion acquires a pasty +consistency. In this way, the acids present are separated into two +classes: (_a_) those that are sufficiently volatile to have passed into +the receiver, such as, acetic, nitric, hydrochloric and sulphuric acids +(the latter acid will only be partially volatilized); and (_b_) those +that remain in the retort. The former are detected by examining the +distillate as previously directed. + +The residue remaining in the retort is treated with absolute alcohol, +the fluid filtered, and a solution of acetate of lead added to the +filtrate: sulphuric, phosphoric and oxalic acids, if present, are +precipitated. The precipitate is suspended in water and decomposed by +means of sulphuretted hydrogen. The acids contained are now set free, +and are detected by applying the tests already mentioned. + +If there be reason to suspect the presence of both sulphuric and oxalic +acids, the distillation is discontinued after a short time. The two +acids are dissolved by shaking the moderately concentrated fluid +remaining in the retort with ether, and, upon evaporating the solution, +will be obtained in a state suitable for examination. Oxalic acid is +then detected by means of sulphate of lime; sulphuric by means of +oxalate of baryta. + +The above examinations would fail to effect the detection of +_phosphorus_, and it is necessary to examine a separate portion of the +original substance for this body. + + + + +IV. + +MISCELLANEOUS EXAMINATIONS. + + +DETERMINATION OF THE NATURE AND COLOR OF THE HAIR AND BEARD. + +A criminal, in order to conceal his identity, may change the color of +the hair and beard by artificial means; either to a darker shade, in +case they were naturally of a light color, or, to a lighter hue, if they +were originally dark, and the chemical expert may be called upon to +detect this artificial coloration, and restore the original color of the +hair. + +It may also happen, that portions of hair still adhere to the clots of +blood sometimes found on an instrument which has been employed in the +commission of a crime, and consequently the question may arise as to the +nature of the hair, whether it be human or animal. + + +DETERMINATION OF THE COLOR OF THE HAIR AND BEARD. + +The mode of examination necessary when the hair has been blackened is +different from that used when it has been decolorized. + + +_The hair has been blackened._ + +As various methods of dyeing hair black are in use, the means of +restoring the original color differ. The following are the methods most +usually employed in dyeing: + +1º. The hair is well rubbed with a pomade, in which finely pulverized +charcoal is incorporated. This preparation, which is sold under the name +of "_mélaïnocome_," possesses the disadvantage of soiling the fingers +and clothing, even for several days after its application. + +2º. The hair is moistened with a dilute solution of ammonia, and a +perfectly neutral solution of a bismuth salt (chloride or nitrate) is +then applied. It is subsequently washed, and allowed to remain in +contact with a solution of sulphuretted hydrogen. + +3º. The same operation is performed, a lead compound being substituted +for the bismuth salt. + +4º. A mixture of litharge, chalk, and slacked lime is applied, and the +head covered with a warm cloth. The hair is afterwards washed, first +with dilute vinegar, then with the yolk of an egg. + +5º. The hair is first cleansed with the yolk of an egg, and then +moistened with a solution of plumbate of lime; or, + +6º. It is moistened with a solution of nitrate of silver, to which a +quantity of ammonia sufficient to dissolve the precipitate first formed +has been added. + +The first method merely causes a mechanical admixture of a coloring +matter with the hair. In the four succeeding processes, a black metallic +sulphide is produced; either by the subsequent application of a solution +of sulphuretted hydrogen, or by the action of the sulphur normally +present in the hair. + +In the last method, the formation of sulphide of silver doubtless +occurs; but the principal change that takes place is probably due to the +action of light, which, as is well known, decomposes the salts of +silver. + +In order to restore the original color to hair which has been treated +with "_mélaïnocome_," it is only necessary to dissolve in ether the +fatty matters present, and then remove the charcoal by washing with +water. + +In case the hair has been dyed by means of a bismuth or lead salt (as in +methods 2, 3, 4 and 5), it is immersed for several hours in dilute +hydrochloric acid: the metal present dissolves, as chloride, and the +original color of the hair is rendered apparent. It then remains to +detect the metal dissolved in the acid solution, in order to establish, +beyond doubt, the fact that a dye has been employed. This is +accomplished by means of the methods used for the detection of metals in +cases of supposed poisoning. + +If, finally, an ammoniacal solution of nitrate of silver has been +employed to cause the coloration, the hair is immersed, for some time, +in a dilute solution of cyanide of potassium, and the fluid subsequently +examined for silver. In case a portion of the salt has been converted +into the sulphide, it will be difficult to restore the original color, +as the removal of this compound is not easily effected. + + +_The hair has been decolorized._ + +Black hair can be bleached by means of chlorine-water, the various +shades of the blonde being produced by the more or less prolonged action +of the reagent. In this case, the odor of chlorine is completely removed +only with great difficulty, and the hair is rarely uniformly +decolorized. The expert may therefore be able to observe indication that +will greatly assist him in arriving at a definite conclusion. The hair +should be carefully examined up to the roots: if several days have +elapsed since the decolorization has been performed, the lower portion +of the hair will have grown and will exhibit its natural color. No +method has yet been proposed that restores the original color to +bleached hair. It is very possible, however, that this end would be +attained by allowing nascent hydrogen to act upon the decolorized hair. +For this purpose, it would be necessary to immerse it in water +containing some sodium amalgam, and slightly acidulated with acetic +acid. + + +DETERMINATION OF THE NATURE OF THE HAIR. + +In examinations of this character use is made of the microscope. The +hair to be examined is suspended in syrup, oil, or glycerine and placed +between two thin glass plates. Human hair is sometimes cylindrical; +sometimes flattened. It consists either of a central canal, or of a +longitudinal series of oblong cavities which contain oily coloring +matter, and possesses the same diameter throughout its entire length. +The brown hair of the beard and whiskers, medium-sized chestnut hair, +the hair of a young blonde girl, and the downy hair of a young man +possess respectively a diameter of 0.03 to 0.15; 0.08 to 0.09; 0.06; and +0.015 to 0.022 millimetres. These exhibit on the surface slightly +projecting scales, which are irregularly sinuous at the border, +separated from each other by a space of about 0.01 m.m., and are +transparent, whatever may be their color. + +The hair of ruminants is short and stiff, and is characterized by +containing cavities filled with air. Wool, however, forms an exception, +as it consists of entire hairs, homogeneous in appearance and possessing +imbricated scales, which bestow upon it the property of being felted. + +The hair of the horse, ox and cow never exceeds 12 m.m. in length, and +is tapering, its diameter gradually diminishing from the base. It is +perfectly opaque, and does not appear to possess a central canal; has a +reddish color, and frequently exhibits lateral swellings, from which +small filaments occasionally become detached, in the same manner as a +twig separates itself from the parent branch. + + +EXAMINATION OF FIRE-ARMS. + +(_Proposed by M. Boutigny._) + +The examination of fire-arms is sometimes useful in determining the date +at which a weapon has been discharged or reloaded. The methods used in +examinations of this nature vary, as the weapon under inspection is one +provided with a flint or an ordinary percussion lock. The value of the +tests employed is also affected by the kind of powder used; _i. e._, +whether common gunpowder, gun-cotton or white gunpowder (prepared by +mixing yellow prussiate of potassa, chlorate of potassa and sugar) has +been taken. + + +THE GUN IS PROVIDED WITH A FLINT-LOCK, AND WAS CHARGED WITH ORDINARY +POWDER. + +In case the weapon has been wiped or exposed to moisture subsequent to +its seizure, it is impossible to form any conclusion as to the date of +its discharge, etc. It is therefore advisable, upon receiving the +weapon, to carefully wrap the lock in a woollen cloth, and to close the +barrel. The exterior of the gun is at first submitted to a careful +examination, and notice taken of the approximate thickness of any +existing rust spots. The fire-pan and adjacent portion of the barrel are +also examined by aid of a magnifying glass, especial attention being +given to the detection of traces of a moist and pulverulent incrustation +of a greyish or blackish color, formed by the combustion of the +gunpowder, and of crystals of sulphate of iron. If the weapon is loaded, +the wad is withdrawn and the color of its cylindrical portion and of the +powder, as well as the size of the ball or shot, noted. + +This preliminary examination ended, the barrel and fire-pan are +separately washed with distilled water, and the washings passed through +filter paper which has previously been well washed, first with pure +hydrochloric acid, then with distilled water. The filtrate is next +divided into three portions, and these separately examined for: (1) +sulphuric acid, by addition of chloride of barium; (2) for iron, by +oxidizing the salts contained in the fluid with a few drops of nitric +acid and adding a solution of ferrocyanide of potassium, the presence of +iron being indicated by the formation of a blue coloration, or a blue +precipitate; and (3) for sulphides, by means of a solution of subacetate +of lead. + +If a bluish-black incrustation is discovered on the fire-pan or on the +neighboring portions of the barrel, and both rust and crystals of +sulphate of iron are absent, and the washings, which were originally of +a light-yellow color, assume a chocolate-brown coloration upon the +addition of solution of subacetate of lead, _the gun has been discharged +within two hours at the longest_. + +If the incrustation possesses a lighter color and traces of iron have +been detected in the washings, but neither rust nor crystals have been +discovered on the barrel or fire-pan, _the weapon has been discharged +more than two, but less than twenty-four hours_. + +In case minute crystals of sulphate of iron and spots of rust are found, +and the washings contain iron in a considerable quantity, _the weapon +has been discharged at least twenty-four hours, at the longest ten +days_. + +If the quantity of rust found is considerable, but iron is no longer to +be detected, _the discharge of the gun occurred ten days, at the longest +fifty days, previously_. + +_If the weapon has been reloaded immediately after its discharge without +having been previously washed_, the portions of the wadding which have +come in contact with the barrel will possess a greyish-black color +during the first four days, the color gradually becoming lighter, until, +at the fifteenth day, it turns grey and remains so permanently. In this +case, the washings will contain sulphuric acid. The objection has been +advanced to the last test that sulphuric acid might be discovered, even +if the gun had not been discharged, if the paper of which the wadding +was made contained plaster. M. Boutigny states, however, that this +objection is untenable, if the wadding has not been moistened by the +water introduced into the barrel. + +_In case the gun has been washed and dried before being reloaded_, the +cylindrical portion of the wadding possesses an ochre-yellow color up to +the first or second day, assumes a decided red hue on the days +following, and acquires a clear rusty color on the sixth day. During the +fifth day the powder also possesses a reddish appearance, owing to an +admixture of rust. Sulphuric acid is not present in the washings. + +_If the weapon has been reloaded immediately after being washed_, the +wadding possesses a greenish-yellow appearance for the first few hours, +and subsequently acquires a reddish color, as in the preceding case. + +_If, finally, the barrel has been washed with turbid lime-water_, rust +is still to be found and the wadding possesses the color mentioned +above. The following colorations are also to be observed in case the gun +has not been washed, or has been dried near a fire: + + BARREL DRIED NEAR A FIRE. UNWASHED BARREL. + After 1 day slight reddish yellow color greenish yellow color. + 2 or 3 days a little darker " reddish-brown " + 4 days a redder " reddish-brown " + 5 or more days a rusty-red " rusty-red. " + + +THE GUN IS NOT PROVIDED WITH A FLINT LOCK. + +At present weapons having flint-locks have almost entirely gone out of +use and have been superseded by the ordinary percussion gun; these +latter, in turn, are being gradually replaced by breech-loaders, charged +with or without a metallic cartridge. The indications obtained in the +preceding examinations by means of the fire-pan, will therefore +disappear; the results given by the inspection of the barrel may +possibly hold good. In regard to breech-loaders, all the useful +indications furnished by the coloration of the wadding and powder fail +to occur; the latter being enclosed either in a paper cylinder or in a +copper socket. + +The fact that gun cotton and white gunpowder are occasionally made use +of, adds to the difficulty of obtaining reliable results by the mere +inspection of a weapon. White gunpowder does not oxidize the gun, fails +to give rise to any salt of iron, and possesses a white color; +gun-cotton produces distinctive indications varying with its purity. +Owing to these facts, it is evident that the method proposed by M. +Boutigny is of no real value, save in the rare instances where a gun +provided with a fire-pan, and charged with ordinary powder, is under +examination, and the question of the lapse of time since the discharge +of a weapon must remain undetermined so far as scientific tests are +concerned. + + +DETECTION OF HUMAN REMAINS IN THE ASHES OF A FIRE-PLACE. + +This class of examinations is particularly necessary when the crime of +infanticide is suspected. As the complete incineration of a cadaver is a +long and difficult operation, it frequently occurs that bones--partially +or completely carbonized, but retaining their original form--are +discovered by the careful examination of the ashes of the fire-place in +which the combustion was accomplished. + +When this is not the case and complete incineration and disaggregation +have occurred, recourse must be had to the indications furnished by a +chemical analysis. These indications are reliable, however, only when +the certainty exists that bones of animals have not been consumed in the +same fire-place; otherwise, the results obtained are entirely worthless, +the reactions given by ashes of animal bones being identical with those +produced by the ashes of a human body. Two tests are employed to detect +the presence of bones in the residue left by the combustion of animal +matter. + +1. A portion of the ashes is placed in a silver crucible, heated with +potassa, and the mass afterwards treated with cold water. If animal +matter is contained in the consumed materials, cyanide of potassium will +be present in the aqueous solution. In order to detect this salt, the +fluid is acidulated with hydrochloric acid, and a solution of +persulphate of iron added: the formation of a blue precipitate indicates +the presence of the cyanide. + +2. The ashes are next examined for phosphate of lime. As wood, coal, and +the other substances usually employed for heating purposes contain none +or little of this salt, its detection in a notable quantity would lead +to the inference that bones have been consumed. The ashes are allowed to +digest for twenty-four hours with one-quarter of their weight of +sulphuric acid. Water is next added to the pasty mixture, and the fluid +filtered. If phosphate of lime be present, it is converted by this +treatment into a soluble acid phosphate, which passes into the filtrate. +Upon adding ammonia to the filtrate, a precipitate of neutral phosphate +of lime is formed, neutral phosphate of ammonia remaining in solution. +The fluid is again filtered, the filtrate acidulated with nitric acid, +and then boiled with a solution of molybdate of ammonia likewise +acidulated with nitric acid: in presence of a phosphate, a yellow +precipitate, or at least a yellow coloration of the fluid, will be +produced. It has been stated that the disengagement of sulphuretted +hydrogen, upon treating the ashes with sulphuric acid, is an indication +that the combustion of a human body has occurred; this reaction is, +however, valueless, inasmuch as coal and certain vegetable ashes +likewise evolve the gas when subjected to the same treatment. + + +EXAMINATION OF WRITINGS. + +Contracts, checks, etc., are frequently altered with criminal intent, +either by erasing the portion of the writing over the signature and +substituting other matter, or by changing certain words, in order to +modify the signification of a sentence. + +Writings are altered either by erasure or by washing. Erasure, although +more easily executed, is seldom employed, as it renders the paper thin +in places, and in this way leaves effects apparent even to the naked +eye, and, although the original thickness can be restored by application +of sandarac or alum, these substances possess properties differing from +those exhibited by paper, and may, moreover, be completely removed, thus +exposing the thinning of the paper. + +In case washing by means of chlorine has been resorted to, the +sizing--which renders the paper non-bibulous, and which is only with +difficulty replaced--may have been removed. Formerly paper was sized by +immersion in a solution of gelatine; at present, however, a soap of +resin, or wax, and alumina (a little starch being added) is more +commonly used. In the latter case, the sizing is less easily removed by +the action of water than when the gelatine preparation is employed; the +detection of its attempted restoration is also a matter of less +difficulty, as gelatine would be employed for this purpose, and this +body possesses properties different from those exhibited by the +substances normally contained in paper: iodine, for instance, which +imparts a yellow color to gelatine, turns starch violet-blue. In order +to detect the alteration of a writing, the following examinations are +made: + +1º. The paper is carefully examined in all of its parts, and in various +positions, by aid of a lens. In this way, either thinned points, caused +by erasure, or remaining traces of words, may possibly be discovered. + +2º. The paper is next placed upon a perfectly clean piece of glass, and +completely and uniformly moistened with water. The glass is then +removed, and the transparency of the paper examined by aid of a lens. +When uniform transparency is exhibited, and certain portions are neither +more transparent nor more opaque than the rest of the paper, it is +probable that erasure has not been attempted. If, on the other hand, +opaque points are observed, it is almost certain that letters have been +erased, and sandarac, which is not affected by water, subsequently +applied. In case transparent points are detected, there is reason to +suspect that words have been removed, and the spots either left intact +or afterwards coated with a substance soluble in water, such as alum. + +3º. The paper is dried and the above operation repeated with alcohol of +87 per cent. Indications may now be observed which failed to occur in +the treatment with water; as well as these latter confirmed. As alcohol +dissolves sandarac, the points that formerly appeared opaque may now +become transparent. + +4º. The paper is again dried, then placed under a sheet of very thin +silk-paper, and a warm iron passed over it. This operation frequently +causes the reappearance of words that have been partially obliterated. +It is also advisable--as suggested by _M. Lassaigne_--to expose the +paper to the action of iodine vapors. If alteration has not been +attempted, the paper will acquire an uniform color; yellow, if sized +with gelatine; violet blue, if sized with the mixture of soap, resin and +starch. When, on the contrary, a subsequent sizing of gelatine has been +applied in order to mask the alteration--the paper having been +originally sized with the above mixture--it will assume in some portions +a yellow, in others a violet-blue color. + +5º. It is ascertained whether the paper possesses an acid reaction. If +so, its acidity may result from the presence of hydrochloric acid, in +case the paper was washed with chlorine, or of other acids. Alum, used +to disguise erasure, would also cause an acid reaction. The mere +detection of acidity is, in itself, of little importance, as, in the +manufacture of paper, the pulp is bleached by means of chlorine, and +this reagent may not have been entirely removed by washing. If, however, +the paper is acid only in certain spots, and these points produce a red +coloration upon blue litmus paper, having the form of letters, the +indication is of value. In order to ascertain if this be the case, it is +advisable, before wetting the paper, to slightly press it upon a sheet +of moist litmus paper: the acid spots will then leave a reddish trace +upon the latter. + +6º. The manuscript under examination is again spread upon a glass-plate, +and a solution of tannin (or preferably, a solution of ferrocyanide of +potassium containing one per cent. of the salt, and acidulated with +acetic acid) applied by means of a brush. If the original writing was +executed with ordinary ink (which has as its base tannate of iron), and +the washing has been but imperfectly performed, it is quite possible +that a blue coloration will be produced by the action of the +ferrocyanide. It is, however, often necessary to apply the above +reagents several times before the original writing becomes apparent; +indeed, in some cases months have elapsed before the reaction has +occurred. + +In case the alteration or destruction of the document is feared in the +above test, it is well to previously provide the court with a certified +copy, and then proceed with the examination. + +7º. If the paper possesses a friable appearance, it has possibly been +washed with sulphuric acid. This property may however originate from +other causes, and the presence of the acid should be confirmed by +washing the document with distilled water, and adding a solution of +chloride of barium to the washings. The precipitate should form in a +considerable quantity, as a slight cloudiness could be due to sulphates +contained in the water used in the preparation of the pulp. + +If much sulphuric acid be present, it may be so concentrated by heating +as to cause the carbonization of the paper. + +8º. It is also well, should washing with sulphuric acid be suspected, to +ascertain, by aid of a lens, if the filaments on the surface of the +manuscript possess an inflated appearance. This would be caused by the +escape of carbonic acid, originating from the action of sulphuric acid +upon the carbonates contained in the water used in the manufacture of +the paper. + +9º. Old ink is more difficult to remove than new, and it is therefore +sometimes possible to cause the reappearance of old writings, over which +words have been subsequently written. For this purpose, a solution +containing 50 per cent. of oxalic acid is applied with a fine brush over +the suspected points. As soon as the ink disappears, the acid is +immediately removed by washing with water, and the paper dried. Upon now +repeating the operation, the presence of a former writing may be +detected after the complete disappearance of the words last written. + +10º. According to _M. Lassaigne_, when the same ink has not been used +throughout a document, washing with dilute hydrochloric acid will +demonstrate the fact. This acid, while causing the gradual obliteration +of characters written with ordinary ink--the shade of the paper not +being altered--produces a red color, if ink containing log-wood has been +employed, and a green coloration, in case the ink used contained +Prussian blue. + +The expert may possibly be called upon to give evidence as to the +existence of a "_trompe-l'oeil_;" as was the case in the trial of _M. de +Preigne_, which took place at Montpelier in 1852. A "_trompe-l'oeil_" +consists of two sheets of paper, glued together at the edges, but having +the upper sheet shorter than the other which therefore extends below it. +This species of fraud is executed by writing unimportant matter on the +uppermost sheet, and then obtaining the desired signature, care being +taken that it is written on the portion of the paper projecting below. +The signature having been procured, it is only necessary to detach the +two sheets in order to obtain a blank paper containing the signature, +over which whatever is desired can be inserted. The trial referred to +above, was in reference to a receipt for 3,000 francs. The expert, upon +placing pieces of moistened paper upon the suspected document, noticed +that they adhered to certain points, and that these formed a border +around the paper but passing _above_ the signature. The fraudulency of +the act was thus established, and so recognized by the court, although +the accused was acquitted by the jury. + +Numerous means have been proposed, in order to render the falsification +of documents a matter of difficulty. The most reliable of these is the +use of "Grimpe's safety-paper," containing microscopic figures, the +reproduction of which is impossible. Unfortunately, up to the present, +the government has adopted methods less sure. + + +EXAMINATION OF WRITINGS IN CASES WHERE A SYMPATHETIC INK HAS BEEN +USED. + +Sympathetic inks are those which, although invisible at the time of +writing, become apparent by the application of certain agents. They are +of two classes: those which are rendered visible by the mere application +of heat, such as chloride of cobalt, or the juice of onions; and those +which are brought out only by the action of a reagent. The inks of the +second class most frequently used are solutions of acetates of lead, and +other metals which give a colored sulphide when treated with +sulphuretted hydrogen. Characters written with a solution of +ferrocyanide of potassium acquire a blue color, if washed with a +solution of perchloride of iron. It is scarcely necessary to add that +the latter solution can be used as the ink, and the ferrocyanide as the +developer. + +When the presence of characters written with a sympathetic ink is +suspected, the document is examined as follows: + +1. The paper is at first warmed: if the ink used is of the first class, +the characters will now become legible; otherwise the examination is +continued as below. + +2. The paper is exposed to the action of steam, in order to moisten the +ink present (care being taken to avoid dissolving the characters), and a +current of sulphuretted hydrogen allowed to act upon it. If the ink used +consists of a lead, bismuth, or gold salt, a black coloration will +ensue; if salts of cadmium or arsenic were employed, the characters will +acquire a yellow color; if, finally, a salt of antimony was used, a red +coloration will be produced. + +3. If no coloration was caused by the action of sulphuretted hydrogen, +it is probably that either a solution of ferrocyanide of potassium or a +persalt of iron has been resorted to. Each of these solutions is +separately applied on a small portion of paper by means of a brush, and +notice taken if the characters become visible. The solution that +produced the change is then applied over the entire sheet. + +4. In case only negative results were obtained in the preceding +operations, it must not yet be concluded that a sympathetic ink has not +been used, although we are left without further recourse to chemical +tests. Numerous organic compounds may have been resorted to, the +detection of which is almost impossible; moreover, if a mistake was made +in regard to the preparation supposed to have been used, the reagents +employed for its detection may render the discovery of another ink +absolutely impossible. It is therefore often necessary to apply +mechanical tests. For this purpose, the paper is spread upon a glass +plate, uniformly moistened with water, and a second plate placed over +it: if the characters were written with a pulverulent substance +suspended in water or mucilage, they may often be observed upon +examining the transparency of the paper. In case the substance used is +both colorless and soluble, the detection of the written characters will +be more difficult; still, indelible traces may possibly have been left +by the pen. If, however, the ink employed is a colorless and transparent +organic compound of rare occurrence, and was applied with a fine +pencil-brush which failed to affect the paper, it must be acknowledged +that little or nothing can be definitely determined as to its presence +or absence. + + +FALSIFICATION OF COINS AND ALLOYS. + +In all civilized countries a fixed standard for coins and precious +alloys is established by law, in order to prevent the perpetration of +frauds which would be of serious injury to the public welfare. The +substitution of coins consisting of an alloy inferior in value to the +standard fixed by law, is too advantageous a fraud not to be often +attempted. + +Coins are most frequently altered by _clipping_; by _stuffing_, that is, +by boring the coin and inserting an alloy of small value; by _doubling_, +which operation consists in covering its face with two thin laminæ taken +from a genuine coin; and by applying a coating of gold or silver by +means of electro-plating. + +In order to ascertain if a coin has been counterfeited, its weight +should at first be determined. If it has been clipped, or consists of an +alloy possessing a density less than that of silver or gold, the fact is +immediately demonstrated by its decreased gravity. + +The coin is further tested by throwing it down upon a hard substance: +gold and silver give a ringing sound, whereas the majority of other +metals produce a dull sound. + +The result obtained by this latter test often fails to be reliable. A +skilful counterfeiter may prepare an alloy equally sonorous and heavy as +silver or gold; in fact, _M. Duloz_ exhibited to the author an alloy, +prepared by him, possessing the density, sonorousness and lustre of +silver; the composition of which, for obvious reasons, has not been +published. + +In instances of this nature the fusibility of the coin should be +determined, and the result obtained compared with the melting point of +the legal alloy, or, this failing, a chemical analysis executed. In +order to perform the latter test, the coin under examination is boiled +with nitric acid: all metals are dissolved, with exception of gold and +platinum, which remain unaltered, and tin and antimony, which are +converted respectively into metastannic and antimonic acids. The fluid +is filtered, the insoluble residue well washed, and then boiled with +hydrochloric acid, which dissolves the metastannic and antimonic acids. +The solution is again filtered, and the second residue dissolved in +_aqua regia_. The metals dissolved in the several filtrates are then +detected, either by the processes previously given for the detection of +metallic poisons, or by the more complete methods contained in works on +chemical analysis. This qualitative test is, however, insufficient, in +case the falsification consisted in merely diminishing the proportions +of the valuable metals contained in the alloy, without changing its +qualitative composition: it is then necessary to execute a quantitative +estimation of the metals present. As this operation requires +considerable practice and the methods employed are to be found in all +treatises on quantitative analysis, we will not reproduce them here. + + +EXAMINATION OF ALIMENTARY AND PHARMACEUTICAL SUBSTANCES. + +We will next enumerate the methods employed in the detection of the +principal adulterations to which flour, bread, oils of seeds, milk, +wines, vinegar and the sulphate of quinine are subjected. These +researches, united with those preceding, fail to embrace all the diverse +examinations which the chemical expert may be expected to execute; but +we do not claim to foresee all the contingencies that may arise, and +will describe the steps to be pursued in instances which are +anticipated, at the same time indicating general methods applicable to +cases not here included. + + +FLOUR AND BREAD. + +The adulterations to which flour and bread are exposed usually consist +in adding damaged or an inferior grade of flour to wheaten flour, or in +disguising the presence of a poor quality of flour by the addition of +mineral substances, such as: plaster, chalk, lime, alum, and sulphate of +copper. + +Good flour has a white color, possessing a slightly yellow tinge, but is +entirely free from red, grey or black specks. It is soft to the touch +and adheres to the fingers, acquiring, when compressed in the hand, a +soft cushion-like form. If mixed with water, it forms an elastic, +homogeneous, but slightly coherent dough, which can be extended out in +thin layers. + +Flour of an inferior quality possess a dull white color, and does not +assume the cushion-like condition mentioned above, when pressed in the +hand, but escapes between the fingers: the dough formed is of a poorer +quality. + +Flour which has been damaged by moisture has a dull or reddish-white +hue, and possesses a mouldy, or even a noxious, odor, as well as a +bitter and nauseous taste which produces a marked acid sensation in the +throat. Occasionally the presence of moisture causes the growth of +_fungi_, the introduction of which in the digestive organs would cause +serious results. + +The constituents of pure flour are: + +_Gluten._ + +_Starch_, in the proportion of 50 to 75 per cent. + +_Dextrine_, in the proportion of several per cent. + +_Glucose_, in the proportion of several per cent. + +_Salts_, remaining in the ash obtained by the calcination of the flour, +in a proportion not exceeding 2 per cent. + +_Water_, of which it loses 12 to 15 per cent., at the heat of a +water-bath, and 15 to 20 per cent., at a temperature of 160°. + +_Bran_, (ligneous and fatty matter,) in a very small proportion, when +the flour has been properly bolted. + +In the process of bread-making, the gluten undergoes fermentation by +the action of the leaven and liberates carbonic acid, which causes the +dough to become porous and swell up, or, as it is termed, to _rise_. +Bread contains the same substances as flour, but gluten and starch are +present in a state that does not admit of their separation by mechanical +means, and glucose, if present at all, exists in a smaller quantity: the +proportion of dextrine and water is, on the other hand, considerably +increased. The bread of the Paris city bakeries contains 40 per cent. of +water--the crumb, which forms 5/6 of the weight of the bread, containing +45 per cent.; the crust, which constitutes the remaining 1/6, containing +15 per cent. In army bread 43 per cent. of water are contained--the +crumb, which constitutes 4/5 of the weight of the bread, holding 50 per +cent.; the crust which forms the remaining 1/5, containing 15 per cent. + +The addition of common salt naturally increases the proportion of ash +left upon calcining bread. + +Water is contained in stale bread in the same quantity as in fresh +bread; but exists in a modified molecular condition: upon heating stale +bread, it acquires the properties of fresh bread. + +The following substances are used in the adulteration of wheaten +flour:[P] + +Potato-starch. + +Meals of various grains (rice, barley, corn, oats and rye). + +Vegetable meals, (beans, horse-beans, kidney-beans, peas, vetch, +lentils, etc.). + +Darnel meal. + +Buckwheat flour. + +Linseed-meal. + +Mineral substances (plaster, chalk, lime, alum, and sulphate of copper). + + [P] Most of the substances here enumerated are rarely, if ever, used + for the adulteration of flour in this country. The analyst should, + however, give attention to the examination for such salts as alum, + sulphate of copper, plaster, kaolin, etc.--_Trans._ + +In order to detect these substances, the gluten, the starch, and the ash +are separately examined. + + +_a._ EXAMINATION OF THE GLUTEN. + +In order to separate the gluten, two parts of the flour to be examined +and one part of water are mixed into a paste, and this is placed in a +fine linen sack, in which it is kneaded under a stream of water so long +as the washings have a turbid appearance: these are preserved. The +gluten obtained from good wheaten flour possesses a light-yellow color; +emits a stale odor; and spreads out, when placed in a saucer. In case +the flour has been too strongly heated in the grinding, or otherwise +badly prepared, the gluten is granulous, difficult to collect in the +hand, and somewhat resembles flint-stone in appearance. + +Gluten prepared from a mixture of equal parts of wheat and _rye_ is +adhesive, blackish, without homogeneousness, spreads out more readily +than pure wheaten gluten, separates easily and adheres somewhat to the +fingers. + +Gluten obtained from a mixture of wheat and _barley_ is non-adhesive, of +a dirty reddish-brown color, and appears to be formed of intertwined +vermicular filaments. + +Gluten formed from a mixture of equal parts of wheat and _oats_ has a +blackish-yellow color and exhibits, at the surface, numerous small white +specks. + +The gluten from a mixture of wheat and _corn_ has a yellowish color, is +non-adhesive, but firm, and does not readily spread. + +Gluten prepared from a mixture of wheat and _leguminous flour_ is +neither cohesive nor elastic, and, if the proportion of the latter +present be considerable, can be separated and passed through a sieve, +like starch. + +The gluten obtained from a mixture of equal parts of wheat and +_buckwheat_ flour is very homogeneous, and is as easily prepared as the +gluten from pure wheaten flour. It possesses when moist a dark-grey +color; which changes to a deep black upon drying. The proportion of +gluten in flour is exceedingly variable: good flour contains from 10 to +11 per cent. of dry gluten; poor flour from 8 to 9 per cent. of moist +gluten, equal to about one-third of its weight of the dry compound. + + +_b._ EXAMINATION OF THE STARCH. + +The washings of the flour are allowed to stand for some time in a +conical-shaped vessel. As soon as the amylaceous matter has entirely +settled to the bottom of the vessel, the greater portion of the water is +decanted, and the residual mass brought upon a small filter and allowed +to dry. The residue is then examined for potato and rice starch. + +_Potato starch._ The grains of potato starch are much larger than those +of wheaten starch. If a portion of the residue mentioned above is +crushed in an agate mortar, the granules of potato starch present are +ruptured, and their contents liberated; the wheaten starch remaining +unaltered. The mass is then taken up with water, and the fluid filtered. +If potato starch be present, the filtrate will acquire a blue color upon +addition of an aqueous solution of iodine; otherwise, a yellow or +violet-rose coloration is produced. It is necessary to avoid crushing +the residue for too long a time, as the granules of wheaten starch would +also become ruptured by prolonged comminution. + +Besides the difference presented by potato starch in the size of the +granules in comparison to those of wheaten starch, the former swell to +ten or fifteen times the volume of the latter, when treated with a +solution of potassa: wheaten starch granules are not affected by the +treatment, if the solution used does not contain more than 2 per cent. +of the salt. The results obtained by the above operation should be +confirmed by a microscopic examination. + +A portion of the residue is moistened with solution of iodine, then +carefully dried, and placed on the slide of a microscope. The mass is +next moistened with a solution containing 2 per cent. of potassa, and +examined. The addition of iodine causes the potato starch granules to +acquire a blue color, and renders their shape and volume more easily +perceptible; thus allowing the two varieties of starch to be readily +distinguished. Fig. 13 represents the relative size of the granules as +observed under the microscope.[Q] + + [Q] It may be added, as a distinguishing property, that granules of + potato starch, when viewed in polarized light by aid of a Nicol's + prism, present a well-defined black cross, corresponding to the hilum; + wheaten-starch fails to exhibit this phenomenon.--_Trans._ + + [Illustration: Fig. 13.] + +The presence of potato starch in bread is also detected by crushing a +small portion of the sample under examination on the glass, and then +adding a few drops of the alkaline solution. + +_Rice and Corn._--If rice or corn meal have been mixed with the flour, +angular and translucent fragments (Fig. 14) are observed in the +microscopic examination. Corn meal acquires a yellow color, if treated +with dilute potassa solution. + + [Illustration: Fig. 14.] + + +MISCELLANEOUS TESTS. + +_Linseed and rye meals._--If linseed meal is moistened with an aqueous +solution containing 14 per cent. of potassa and examined under the +microscope, numerous minute characteristic granules, smaller than the +grains of potato-starch, are observed. These possess a vitreous +appearance, sometimes a reddish color, and usually form in squares or +very regular rectangles. The test is equally applicable to bread. The +detection of linseed and rye meals is simultaneously effected by +exhausting the suspected flour with ether, then filtering the solution +and allowing it to evaporate. If the flour contains rye, the oil left by +the evaporation, when heated with a solution of mercury in concentrated +nitric acid, is converted into a solid substance having a fine red +color; but it remains unaltered, if entirely due to linseed. In case the +oil becomes solidified, the mercury salt present should be removed by +washing with water, the residue taken up with boiling alcohol of 36° B. +and the solution filtered: upon evaporating the alcoholic filtrate, a +residue is obtained consisting of the linseed oil present. + +_Buckwheat._--Flour adulterated with buckwheat is less soft to the +touch, does not pack as easily, and passes more readily through a sieve +than pure wheaten flour. It presents, here and there, blackish +particles, due to the perisperm of the grain, and has a dirty-white +color. As previously remarked, the gluten obtained from a mixture of +buckwheat and wheaten flour possesses a grey or even a black color. The +starch furnished by buckwheat flour exhibits polyhedral agglomerations, +analogous to those presented by corn. + +_Darnel._--The use of darnel in the adulteration of wheaten flour may +give rise to serious sanitary results. To effect its detection, the +flour to be examined is digested with alcohol of 35° B.: if the flour be +pure, the alcohol remains limpid: it acquires a straw-yellow tint, due +to traces of bran present, but--although a peculiar resin may be +dissolved--the solution does not possess a disagreeable taste. When, on +the contrary, darnel is present, the alcohol assumes a green tint, which +gradually deepens, and possesses a bitter and nauseous taste; the +residue, left by the evaporation of the tincture to dryness, has a +greenish-yellow color, and a still more disagreeable flavor than the +alcoholic solution. + +_Legumens._--Leguminous meals cannot be added otherwise than in small +proportions to wheaten flour, owing to the rapidity with which they +change the properties of the latter, and communicate to it their +characteristic odor--noticeable upon treating the flour with a little +boiling water. Their presence is also easily detected by the distinctive +properties of the vegetable itself, and by the appearance of the +amylaceous residue in the microscopic examination. In order to decide as +to the presence of legumens, the washings containing the starchy matter +of the flour, after the particles of gluten present have been separated +by passing the fluid through a silk sieve, are divided into two +portions. One portion is allowed to undergo fermentation, at a +temperature of 18° to 20°: in case leguminous substances are not +present, lactic fermentation occurs and the odor of sour milk is alone +perceptible; if, on the other hand, legumens are contained in the fluid, +rancid fermentation takes place, and an odor is emitted resembling that +of decayed cheese. The remaining portion of the washings, after being +decanted from the residue of amylaceous matter, is filtered and +evaporated until a yellowish translucent pellicle appears upon its +surface. The fluid is then again filtered from the coagulated albumen +common to all flours, and the leguminous substances present coagulated +by the addition, drop by drop, of acetic acid. + +The leguminous deposit produced appears white and flaky; when examined +under the microscope, it presents lamilla emarginated at the border; it +is odorless and tasteless; when dried, it assumes a horny appearance; it +is insoluble, both in water and alcohol, and does not become gelatinous +when treated with boiling water; it is readily soluble in potassa and +other alkaline solutions, from which it is precipitated upon addition of +nitric, hydrochloric, acetic, oxalic, and citric acids; upon protracted +boiling in water, it loses its property of being soluble in ammonia. The +above tests having been applied, the residue containing the starch is +next examined. For this purpose, a small portion is moistened with a +little water, a few drops of iodine solution added, and the mixture +placed on the side of the microscope: the bluish grains contained in the +polyhedral and cellular envelope (Fig. 15) are easily recognized. The +mixture on the glass may also be treated with an aqueous solution of +potassa (containing 10 per cent. of the salt), or with dilute +hydrochloric acid: these reagents dissolve the starch present, leaving +the reticulated tissue intact. Should this examination fail to give a +definite result, the remaining portion of the amylaceous residue is +subjected to a sort of levigation, and the part most slowly deposited +separated. In this portion the reticulated tissues of the leguminous +substances present are contained, and, as they are comparatively free +from foreign matters, their identification is a matter of comparative +ease. In case the presence of reticulated tissue is indicated, it is +still necessary to apply confirmatory chemical tests. + + [Illustration: Fig. 15.] + +Meals prepared from beans, horse-beans, and lentils, contain a tannin +which imparts a green or black color to salts of iron. The coloration is +rendered very sensitive if a rather considerable quantity of the flour +to be examined is passed through a silk sieve, and the remaining bran +treated with a solution of sulphate of iron (_ferrico-ferrous_ +sulphate): the reaction immediately occurs, even if the sample contains +but 10 per cent. of bean meal. The meals of horse-beans and of vetches +acquire a red color, when exposed to the successive action of nitric +acid and of ammonia vapors. In order to apply this test, the suspected +flour is placed upon the edge of a capsule containing nitric acid, the +latter heated, and, as a yellow coloration appears, the acid removed and +replaced by ammonia. The capsule is then set aside: if the flour is +adulterated with either of the above vegetables, reddish spots, which +are easily perceptible by aid of a magnifying glass, are soon produced. + +In case bread is to be examined, it is exhausted with water, the fluid +passed through a sieve, the upper layer decanted, then evaporated, and +the residue taken up with alcohol. The tincture so obtained is +evaporated, and the second residuum treated with nitric acid and +ammonia, as directed above. When meals prepared from beans, vetches, or +lentils are heated on a water-bath with hydrochloric acid, diluted with +three to four times its volume of water, a cellular tissue, possessing +the color of wine-dregs, remains behind; flours of wheat, peas, and +kidney-beans leave a colorless residue, when subjected to the same +treatment. + +Finally; the grains of the starch (_fecula_) of legumens possess a +volume about equal to that of potato granules, and exhibit either a +longitudinal furrow in the direction of their longer axis, or a double +furrow arranged in a star-like form. + + +_c._ EXAMINATION OF THE ASH. + +Leguminous substances, and more particularly mineral salts, are detected +by the examination of the ash left upon the incineration of the flour. + +_Detection of Legumens._--Pure wheaten flour furnishes an ash consisting +of about 2 per cent. of its weight; whereas meals of legumens leave from +3 to 4 per cent. of their weight in ash. This difference is, however, +too slight to furnish conclusive results; the analysis of the ash is +also necessary. The ash of wheaten flour is non-deliquescent, dry, +semi-fused, and chiefly consists of phosphates of potassa, soda, +magnesia and lime, of sulphates, and of silica. The solution obtained by +treating the ash with water has an alkaline reaction. The phosphates of +the alkalies, present in the ash of wheat, exist in the state of +pyrophosphates, and, as chlorides are absent, the addition of nitrate of +silver to the aqueous solution of the ash produces a white precipitate, +consisting entirely of pyrophosphate of silver, which is not affected by +exposure to the light. + +The ash of leguminous meals is deliquescent and soluble in water, +forming a _strongly_ alkaline solution, which contains both chlorides +and _neutral_ phosphates. The latter give a clear yellow precipitate +with nitrate of silver. Upon adding a solution of this salt to the +aqueous solution of the ash, a _pale_ yellow precipitate, which turns +violet if exposed to the light, is therefore produced. + +_Detection of mineral substances._--The principal mineral substances, +that are fraudulently added to flour, are ground calcined bones, sand, +lime, plaster, alum, and sulphate of copper. The two last named salts +are almost invariably added in small quantities; alum renders the flour +white, even when used in the proportion of one per cent.; sulphate of +copper is added to impart a good appearance to bread made from a damaged +flour. + +_a. Ground bones_ (carbonate and phosphate of lime).--The washings of +the gluten are placed in a conical vessel, and, after some time has +elapsed, the clear supernatant fluid is removed by means of a syphon, a +conical shaped deposit remaining on the bottom of the vessel: two hours +later, the fresh layer of fluid that has formed is removed with a +pipette. As soon as the residue becomes nearly solid, it is detached +from the vessel, placed upon a fragment of plaster, and allowed to dry. +The bones, being heavier than the amylaceous substances, are to be found +in the apex of the cone formed by the residue. This is detached, and +incinerated: in case the ash obtained contains phosphate and carbonate +of lime, the addition of hydrochloric acid will cause effervescence, +and, upon adding ammonia to the acid solution, a white precipitate will +be formed. If the solution is then filtered and oxalate of ammonia added +to the filtrate, a precipitate will be produced which, when heated to +redness, leaves a residue of caustic lime possessing an alkaline +reaction. + +_b. Sand._--As this substance possesses a much greater specific gravity +than the usual constituents of flour, it is only necessary, in order to +accomplish its separation, to repeatedly stir the flour with water, and +remove the deposit at first formed, which, if consisting of sand, will +be insoluble in acids, and will grate, when placed between the teeth. + +_c. Carbonates of lime and magnesia; vegetable ashes._--Carbonic acid +is always evolved, upon treating flour with hydrochloric acid. If the +base present be calcium, upon adding oxalate of ammonia to the filtered +solution--which has previously been neutralized with ammonia--a white +precipitate, possessing the properties mentioned above, will be formed; +in case the base is magnesia, the addition of oxalate of ammonia will +fail to cause a precipitate, but upon adding solution of phosphate of +ammonia to the fluid a granular precipitate of phosphate of ammonia and +magnesia is produced; if, finally, the flour contains vegetable +ashes--_i. e._ carbonates of the alkalies--bichloride of platinum will +produce in the acid solution a yellow precipitate: the addition of +vegetable ashes, moreover, would render the ash of the flour +deliquescent and very strongly alkaline. + +_d. Lime._--In presence of lime, carbonic acid produces a white +precipitate, when conducted into the filtered aqueous extract of the +flour. + +_e. Plaster._--The flour is boiled with water acidulated with +hydrochloric acid, the fluid filtered, and lime detected in the filtrate +by means of ammonia and oxalate of ammonia. The presence of sulphuric +acid is indicated by the formation of a precipitate insoluble in acids, +upon addition of solution of chloride of barium. Upon calcining the +flour without access of air, sulphate of lime is converted into the +corresponding sulphide: the residue of the calcination, when treated +with hydrochloric acid, evolves sulphuretted hydrogen, and the lime +present in the filtered acid solution is likewise precipitated by the +addition of ammonia and oxalate of ammonia. + +_f. Alum._--A portion of the flour to be examined is treated with water, +the fluid filtered, and the filtrate divided in two portions: in one, +sulphuric acid is detected by means of chloride of barium; in the other, +alumina by adding a solution of potassa, which gives with its salts a +white gelatinous precipitate, soluble in an excess of the reagent.[R] + + [R] If the detection of alum in bread is desired, a portion of the + crumb is incinerated in a platinum dish, the ash is treated with + concentrated hydrochloric acid, the filtered solution evaporated to + dryness, and the residue treated with hydrochloric acid, which now + leaves the silica present undissolved. The acid solution is then + filtered, nearly neutralized with carbonate of soda, and an alcoholic + solution of potassa added in excess. The earthy phosphates present are + now precipitated, alumina remaining in solution. The use of aqueous + potassa in this case--as well as in the case mentioned in the text--is + not advisable, as it is seldom entirely free from alumina. Upon + slightly acidulating the alkaline filtrate with hydrochloric acid, and + adding carbonate of ammonia, the alumina present is precipitated, and + may be dried and tested by means of the reaction with nitrate of + cobalt before the blow-pipe. + + In the quantitative estimation of alumina, the phosphoric acid + usually present in the precipitate should be removed. This is done by + dissolving the precipitate in nitric acid and immersing a piece of + metallic tin in the boiling solution: phosphoric acid is thrown down + as a mixture of stannic oxide and phosphate, and the alumina is then + precipitated as usual by carbonate of ammonia.--_Trans._ + +_g. Sulphate of copper._--About 200 grammes of the bread under +examination are incinerated; the ash treated with nitric acid; the +mixture evaporated until it acquires a sticky consistence, and the mass +then taken up with water. The aqueous solution is next filtered; an +excess of ammonia and several drops of solution of carbonate of ammonia +added; the fluid again filtered, the filtrate slightly acidulated with +nitric acid, and divided into two parts. It is then ascertained if +sulphuretted hydrogen produces in one portion of the solution a brown +precipitate of sulphide of copper, and if solution of ferrocyanide of +potassium produces in the other a reddish-brown precipitate of +ferrocyanide of copper.[S] + + [S] According to Wagner, if the ash, obtained by incinerating the + adulterated bread, is washed with water, shining spangles of metallic + copper are separated.--_Trans._ + + +FIXED OILS. + +Olive oil designed for table use is frequently adulterated with the oils +of poppy, sesamé, cotton-seed, pea-nuts, and other nuts; olive oil, +intended for manufacturing purposes, is often mixed with colza and nut +oils. + +The tests used are of a rather unsatisfactory character. In all +instances, when the chemist is called upon to pronounce as to the +adulteration of an oil, it is necessary to execute comparative +experiments with the pure oil, and with admixtures arbitrarily prepared: +it is only when this is done that the indications obtained are of value. + + +EXAMINATION OF OLIVE OIL INTENDED FOR TABLE USE. + +_a._ The density of the oil is determined by means of a hydrometer +(_oleometer_) provided with a scale giving the densities from 0.8 to +0.94, for the temperature of 15.° Pure olive oil possesses a specific +gravity of 0.917; poppy oil one of 0.925; a mixture of the two, an +intermediate density. Since the fixed oils are not definite chemical +compounds, this test is seldom conclusive. + +_b._ Two or three cubic centimetres of concentrated nitric acid, +containing nitric peroxide in solution (or a solution of mercury in +strong nitric acid), are added to the oil to be examined, as well as to +a sample of pure olive oil. The two samples are then allowed to stand in +a room where the temperature does not exceed 10.° The _oleine_ of the +olive oil is converted into solid _elaidine_, and the mixture after some +time becomes sufficiently thick to remain in the vessel upon inversion. +If the sample under examination is free from adulteration, it will +solidify at the same time as the pure oil; whereas, the presence of one +per cent. of poppy oil, or of other drying oils, suffices to retard the +solidification for forty minutes. + +_c._ Fifteen grammes of the oil are mixed in a glass vessel with the +same amount of strong sulphuric acid, the temperature of the two liquids +being previously observed. The mixture is stirred with a thermometer, +and the maximum temperature noted: pure olive oil produces an elevation +of temperature of 37.°7; pure poppy oil, an elevation of 70.°5; and a +mixture of the two an elevation of temperature intermediate between +37.°7 and 70.°5. + +_d._ One volume of nitric acid of sp. gr. 1.33 is agitated with 5 +grammes of the oil, and notice taken of the coloration produced after +the lapse of five minutes. If the olive oil is pure, it acquires a pale +green color; in case it is mixed with sesamé or nut oil, a deep-red +color appears: poppy oil also communicates a reddish coloration, but one +less deep than the preceding. + +If an acid of sp. gr. 1.22 is taken, it is still less difficult to +distinguish between sesamé, nut and poppy oils; the latter assumes, in +this case, a pale yellowish-red color. + +Pea-nut oil fails to exhibit a coloration; but can be recognized by its +conversion into a white solid, when mixed with 1/5 of its volume of a +solution of caustic soda of sp. gr. 1.34. + + +EXAMINATION OF OLIVE OIL INTENDED FOR MANUFACTURING PURPOSES. + +The chief adulterations are colza and nut oils. The latter is detected +by means of the reaction with nitric acid, as described above. Colza oil +is recognized by mixing 5 volumes of the sample to be examined, with 1 +volume of sulphuric acid of sp. gr. 1.655: if colza or nut oils are +present, a brown coloration ensues; under the same circumstances, pure +olive oil assumes a pale greenish hue. In case the sample acquires a +brown color when treated with sulphuric acid, and a red coloration is +produced by the addition of nitric acid, it contains nut oil; if +sulphuric acid produces a brown coloration, and nitric acid fails to +change it, the presence of oil of colza is indicated. + + +EXAMINATION OF HEMPSEED OIL. + +This oil is frequently adulterated with linseed oil. The reactions +exhibited by these oils are nearly identical, and the detection of the +admixture is extremely difficult. It is advisable to mix the suspected +oil with sulphuric acid, notice being taken of the elevation of +temperature produced, and to treat it with nitric acid and with dilute +potassa solution, subjecting, at the same time, an artificial mixture of +the two pure oils to the same treatment, and comparing the results +obtained. + + +TEA AND ITS ADULTERATION. + +Among alimentary substances probably no article is subjected to more +adulteration than tea. The sophistications practised may be conveniently +divided into three classes: + +1. Additions made for the purpose of giving increased bulk and weight, +which include foreign leaves and exhausted tea-leaves, and also certain +mineral substances, such as metallic iron, sand, brick-dust, etc. + +2. Substances added in order to produce an artificial appearance of +strength in the tea decoction, catechu, or other bodies rich in tannin, +and iron salts being chiefly resorted to for this purpose. + +3. The imparting of a bright and shining appearance to the tea by means +of various coloring mixtures or "facings," which adulteration, while +sometimes practised upon black tea, is much more common with the green +variety. This sophistication involves the use of steatite (soap-stone), +sulphate of lime, China clay, Prussian blue, indigo, turmeric, and +graphite; chromate of lead and copper salts being but very rarely +employed. The compound most frequently used consists of a mixture of +soap-stone (or gypsum) with Prussian blue, to which a little turmeric is +sometimes added. + +Genuine tea is the prepared leaf of _Thea sinensis_. It contains: +moisture, 6% to 10%; theine, 0.4% to 4.0%; tannin, (green) 20%, (black) +10%; ash, 5% to 6%; soluble extractive matters, 32% to 50%; and +insoluble leaf, 47% to 54%. + + [Illustration: Fig. 16.] + + [Illustration: Fig. 17.] + + [Illustration: Fig. 18.] + + [Illustration: Fig. 19.] + +The presence of foreign leaves, and, in some instances, of mineral +adulterants, in tea is best detected by means of a microscopic +examination of the suspected sample. The genuine tea-leaf is +characterized by its peculiar serrations and venations. Its border +exhibits serrations which stop a little short of the stalk, while the +venations extend from the central rib, nearly parallel to one another, +but turn just before reaching the border of the leaf (see Fig. 16). The +Chinese are said to employ ash, plum, camellia, velonia, and dog-rose +leaves for admixture with tea, and the product is stated to be often +subjected in England to the addition of the leaves of willow, sloe, +beech, hawthorn, elm, box-poplar, horse-chestnut, and fancy oak (see +Figs. 17, 18, and 19). For scenting purposes chulan flowers, rose, +jasmine, and orange leaves are frequently employed. In the microscopic +examination the sample should be moistened with hot water, spread out +upon a glass plate, and then submitted to a careful inspection, especial +attention being given to the general outline of the leaf and its +serrations and venations. Most foreign leaves will, in this way, be +identified by their botanical character. The presence of exhausted +tea-leaves may also often be detected by their soft and disintegrated +appearance. If a considerable quantity of the tea be placed in a long +glass cylinder and agitated with water, the coloring and other abnormal +bodies present frequently become detached, and either rise to the +surface of the liquid as a sort of scum or fall to the bottom as a +deposit. In this way Prussian blue, indigo, soap-stone, gypsum, sand, +and turmeric can sometimes be separated and subsequently recognized by +their characteristic microscopic appearance. The separated substances +should also be chemically tested. Prussian blue is detected by heating +with a solution of caustic soda, filtering, and acidulating the filtrate +with acid, and then adding chloride of iron, when, in its presence, a +blue color will be produced. Indigo is best discovered by its appearance +under the microscope; it is not decolorized by caustic alkali, but it +dissolves in sulphuric acid to a blue liquid. Soap-stone, gypsum, sand, +metallic iron, etc., are identified by means of the usual chemical +tests. A compound, very aptly termed "Lie-tea," is often met with. It +forms little pellets consisting of tea-dust mixed with foreign leaves, +sand, etc., and held together by means of gum or starch. This, when +treated with boiling water, falls to powder. In the presence of catechu +the tea infusion usually becomes muddy upon cooling; in case iron salts +have been employed to deepen the color of the liquor, they can be +detected by treating the ground tea-leaves with acetic acid and testing +the solution with ferrocyanide of potassium. Tea should not turn black +upon immersion in hydrosulphuric acid water, nor should it impart a blue +color to ammonia solution. The infusion should be amber-colored, and not +become reddened by the addition of an acid. + + +TEA ASSAY. + +In the following tea assay proper the estimation of theine is not +included. The processes suggested for this determination are rather +unsatisfactory; and there appears, moreover, to exist no direct relation +between the quality of tea and the proportion of theine contained. The +tests here mentioned, in connection with those already given, will, it +is believed, usually suffice to indicate to the analyst the presence of +spent leaves, inorganic coloring matters, and other mineral +adulterations. + +TANNIN.--A good process for the estimation of tannin in tea has been +published by Allen (_Chem. News_, vol. xxix. p. 169 et seq.) A standard +solution of lead acetate is prepared by dissolving 5 grammes of the salt +in distilled water and diluting the liquid to 1,000 c.c. As an +indicator, 5 milligrammes of potassic ferricyanide are dissolved in 5 +c.c. of water, and an equal volume of strong ammonia-water added. The +exact strength of the lead solution is to be determined by means of a +solution of pure tannin of known strength. Two grammes of the tea to be +tested are powdered, boiled with water, and, after filtering and +thorough washing, the decoction is made up to a volume of 250 c.c.; 10 +c.c. of the lead solution are now diluted with 90 c.c. of boiling water, +and the tea infusion is gradually added from a burette until a few drops +of the liquid, when filtered and added to a little of the indicator +placed upon a porcelain slab, causes a pink coloration to appear; 125, +divided by the number of c.c. of tea infusion found to be necessary to +produce the pink color, will give directly the percentage of tannin in +the sample examined. As previously stated, green tea contains 20% of +tannin, and black tea 10%. In spent tea, however, only about 2% of +tannin is present; and, although any tea deficient in this constituent +could be fortified by the addition of catechu, its determination often +affords indications of value. + +THE ASH--_a. Total Ash._--5 grammes of the sample are placed in a +platinum vessel and heated over a Bunsen burner until complete +incineration has been accomplished. The vessel is allowed to cool in a +desiccator, and is then weighed as quickly as possible. In genuine tea +the total ash should not be much below 5% or much above 6%, and it +should not be magnetic; in "faced" teas the proportion of total ash is +often 10% or 15%; in "lie-tea" it may reach 30%, and in spent leaves it +may fall as low as 3%, the ash in this case being abnormally rich in +lime salts and poor in potash salts. Tea-dust sometimes contains 10% of +total ash without necessarily being considered bad in quality. In the +proposed United States tea-adulteration law (1884) a maximum of 8% of +total ash is allowed for tea-leaf. + +_b. Ash insoluble in water._--The total ash obtained in _a_ is washed +into a beaker and boiled with water for a considerable time. It is then +brought upon a filter and the insoluble residue washed, dried, ignited, +and weighed. In unadulterated tea it will not exceed 3% of the sample +taken. + +_c. Ash soluble in water._--This proportion is obtained by deducting ash +insoluble in water from the total ash. Genuine tea contains from 3% to +3.5% of soluble ash, or at least 50% of the total ash, whereas in spent +or exhausted tea the amount is often but 0.5%. + +_d. Ash insoluble in acid._--The ash insoluble in water is boiled with +dilute hydrochloric acid and the residue separated by filtration, +washed, ignited, and weighed. In pure tea the remaining ash ranges +between 0.3% and 0.8%; in "faced" teas, or in teas adulterated by the +addition of sand, etc., it may reach the proportion of 2% to 5%. +Fragments of silica and brick-dust are occasionally to be found in the +ash insoluble in acid. + +THE EXTRACT.--Two grammes of the carefully-sampled tea are boiled with +water until all soluble matter is dissolved, water being added from time +to time to prevent the solution becoming too concentrated. The solution +is poured upon a tared filter, and the remaining insoluble leaf +repeatedly washed with hot water until the filtered liquid becomes +colorless. The filtrate is now diluted to a volume of 200 c.c., and of +this 50 c.c. are taken and evaporated in a weighed dish over the +steam-bath until the weight of the extract remains constant; its weight +is then determined. Genuine tea affords from 32% to 50% of extract, +according to its age and quality; in spent tea the proportion of extract +will be greatly reduced. + +INSOLUBLE LEAF.--The insoluble leaf obtained in the preceding operation, +together with the weighed filter, is placed in an air-bath and dried for +at least eight hours at a temperature of 110° C.; its weight is then +determined. In unadulterated tea the amount of insoluble leaf ranges +between 47% and 54%; in exhausted tea it may reach a proportion of 75%. + +It should be noted that in the foregoing estimations the tea is taken in +its ordinary air-dried condition. If it be desired to reduce the results +obtained to a dry basis, an allowance for the moisture present in the +sample (an average of 8%), or a direct determination of the same, must +be made. + +The following tabulation gives the constituents of genuine tea so far as +the ash, extract, and insoluble leaf are involved: + +_Total ash_--ranges between 4.7% and 6.2%. + +_Ash soluble in water_--ranges between 3% and 3.5%; should equal 50% of +total ash. + +_Ash insoluble in water_--not over 2.75%. + +_Ash insoluble in acid_--ranges between 0.3% and 0.8%. + +_Extract_--ranges between 32% and 48%. + +_Insoluble leaf_--ranges between 43% and 58%. + +The table below may prove useful as indicating the requirements to be +exacted when the chemist is asked to give an opinion concerning the +presence of facing admixtures or of exhausted or foreign leaves in a +sample of tea: + +_Total ash_--should not be under 4.5% or over 7%. + +_Ash soluble in water_--should not be under 40% of total ash. + +_Ash insoluble in water_--should not be over 3%. + +_Ash insoluble in acid_--should not be over 1%. + +_Extract_--should not be under 30%. + +_Insoluble leaf_--should not be over 60%. + +NOTE.--The British Society of Public Analysts adopt: + +_Total Ash_ (dry basis)--not over 8% (at least 3% should be soluble in +water). + +_Extract_ (tea as sold)--not under 30%. + + +MILK. + +The chief constituents of milk are water, butter, caseine, lactose +(milk-sugar), traces of albumen and mineral salts. Butter is present in +the form of minute globules, held in suspension; the caseine, for the +greater part, is in solution, only a small portion being present in an +insoluble suspended condition. In milk only a few days old, the +_colostrum_ (the milk secreted during the first few days after +parturition) consists largely of rather voluminous cellular +conglomerations, containing a sufficient quantity of albumen to +coagulate upon heating. + +The normal density of milk is 1.030, water being 1.000; the density +rising to 1.036, if the fluid has been skimmed. + +Good milk contains, on an average, 3.7 per cent. of butter; 5.7 per +cent. of lactose, and leaves upon evaporation 12 to 14 per cent. of +solid matters.[T] The most common adulteration of milk consists in the +addition of water. This fraud is detected by means of an areometer +(_lactodensimeter_) which gives directly the specific gravity of the +fluid under examination. Should the density be much below 1.030, it is +certain that water has been added. It does not, however, necessarily +follow if it is about 1.030 that the milk is pure, since the gravity of +the fluid, which would be increased upon skimming, could be subsequently +reduced to 1.030 by the addition of water. The lactodensimeter, +therefore, although useful in the detection of a simple admixture, fails +to give reliable results if the fraud perpetrated is a double one; and a +determination of the proportion of butter present is also usually +necessary. Numerous methods have been proposed to accomplish this +estimation. The most preferable of these, owing to the rapidity with +which the operation is executed, is the use of the lactoscope +(_galactoscope_). This instrument consists of a tube provided with a +glass plate fitted at one end, and with a movable glass plate at the +other extremity. A few drops of the milk to be tested are placed between +the two plates, and the tube lengthened, by screwing out the movable +plate, until the fluid no longer transmits the light of a candle placed +at a distance of one metre. As the opacity of milk is due to the butter +present, it is evident that the proportion of this substance contained +in the sample can be estimated by the relative distance which the plates +have been separated. + + [T] The British Society of Public Analysts regard the following as the + _minimum_ proportions of constituents in unadulterated milk: + + Fat 2.5 per cent. + Solids, not fat 9. " " + ---- + Total 11.5 " " + Water 88.5 " " + + --_Trans._ + +The lactoscope possesses, however, but a limited degree of precision. +_M. Marchand_ substitutes to its use the following tests: A test-tube is +graduated in three equal divisions, the upper one being subdivided into +hundredths extending above, in order to determine accurately the correct +volume of the fluid, expanded, as it is, by the temperature of 40°, at +which the examination is executed. The first division of the tube is +filled with milk, a drop, or two of strong potassa lye added, and the +mixture well shaken: the second portion is then filled with ether, and +the third with alcohol. The mixture is next again thoroughly agitated, +and then exposed to a temperature of 40° in a water-bath. After standing +for several hours, a layer of fatty matter becomes sufficiently +separated to allow of measurement: but, as it contains some ether and as +a small amount of butter may still be retained in the lower aqueous +fluid, a correction of the results obtained is necessary. M. Marchand +has compiled a table, which facilitates this correction (_vide_: _Journ. +de Pharm., Novembre 1854_, and _Bulletin de l'Académie de Médecine, +Paris, 1854_, xix., p. 1101). + +Previously to the introduction of Marchand's apparatus, use was made of +the _lactometer_, which consists simply of a graduated glass tube, in +which the suspected milk is allowed to remain for 24 hours, at a +temperature of 15°. After the lapse of this time, the cream present +completely separates as a supernatant layer, the thickness of which +indicates the quality of the sample taken. + +_M. Lacomte_ recommends the addition of glacial acetic acid, in order to +cause the more rapid separation of the cream. + +The estimation of the butter being accomplished, it is frequently +needful to determine the amount of lactose present. For this purpose, +recourse is had to Barreswil's method, based upon the reduction of +cupro-potassic tartrate by milk-sugar in the presence of alkalies. A +solution is prepared containing 40 grammes of pure crystallized sulphate +of copper, 600 or 700 grammes of caustic soda lye of sp. gr. 1.12, and +160 grammes of neutral tartrate of potassa. The sulphate of copper and +tartrate of potassa are previously dissolved separately in a little +water, the three solutions united, and water added until the fluid +acquires a volume of 1154.4 cubic centimetres. In order to standardize +this test solution, a known weight of pure lactose is dissolved in water +and the fluid added, drop by drop, from a graduated burette, to a small +flask containing 10 cubic centimetres of the copper solution, diluted +with 40 cubic centimetres of distilled water, and heated to boiling. At +first a yellow precipitate forms, which gradually turns red, and is +deposited on the bottom of the flask, leaving the solution colorless. As +soon as the test solution is completely decolorized, the addition of the +lactose solution is discontinued, and the weight of lactose +corresponding to 10 cubic centimetres of the test fluid calculated from +the quantity used. The standard of the test solution having been +determined, the above operation is repeated, the milk under examination +being substituted for the solution of pure lactose. The quantity of milk +necessary to decolorize 10 cubic centimetres of the copper solution will +evidently contain the same amount of lactose as the quantity of solution +used in the preliminary test, and the actual amount of lactose present +is very easily calculated. When an estimation of the solid matter +contained in the milk is required, a known weight is evaporated to +dryness over a water-bath, and the residue weighed. In performing this +evaporation, the addition of a known amount of sand, or ground glass, is +advisable. The amount of ash present is determined by incinerating the +residue left by the evaporation. + +Foreign substances are sometimes added to milk, for the purpose of +disguising the presence of an abnormal quantity of water, the principal +of which are: chalk, bicarbonate of soda, emulsion of almonds, gum +tragacanth, gum arabic, starch, flour, decoction of barley or rice, +sugar, and cerebral substances. These bodies are detected as follows: + +_Chalk._--If chalk is contained in the milk, it readily subsides upon +allowing the sample to remain at rest for some time in a flask, forming +a deposit which effervesces when heated with hydrochloric acid, and +dissolves to a solution, in which the characteristic properties of a +lime salt can be recognized. + +_Bicarbonate of soda._--In presence of this compound the milk possesses +a strongly alkaline reaction, furnishes a serum having a sharp and +bitter taste, and leaves a residue of the salt upon evaporation. + +_Emulsion of almonds._--The milk has a specific gravity of at least, +1.033. If it is passed through a gauze, small opaque lumps are +separated. When examined under the microscope, numerous minute globules, +having a diameter of 1/400 of a millimetre, are observed, and, upon +adding a few centigrammes of amygdaline to one or two grammes of the +milk, the characteristic odor of bitter almonds is produced. + +_Gum tragacanth._--When shaken in a glass flask and allowed to rest, the +milk deposits on the sides small transparent lumps, which usually +present a slightly elongated or angular form. + +_Gum arabic._--The addition of alcohol produces an abundant white opaque +precipitate. + +_Starch, flour, decoction of barley, rice, etc._--Upon boiling the +suspected milk, and adding tincture of iodine, the amylaceous substances +present produce a blue coloration in the fluid. + +_Sugar._--If yeast is added, and the mixture allowed to stand for some +time at a temperature of 30°, alcoholic fermentation ensues; under these +circumstances, lactose does not undergo fermentation. + +_Cerebral substances._--Adulteration by these substances is probably of +much less frequent occurrence than was formerly supposed. The admixture +is detected by evaporating the milk to dryness, dissolving the residue +in ether, evaporating the etherial solution, and fusing the second +residue, which consists of fatty matters, with nitrate of potassa in a +platinum crucible. The mass is then taken up with water, and chloride of +barium added to the solution. If cerebral substances were contained in +the milk, ether will dissolve the fatty matters present, the phosphorus +of which is converted into a soluble phosphate by the calcination with +nitrate of potassa and is thrown down as a white precipitate, upon the +addition of a solution of chloride of barium. This test may be confirmed +by a microscopic examination of the milk, when the peculiar appearance +of cerebral matter will be detected.[U] + + [U] Fragments of nerves, and other organic structures, are frequently + observed in this examination.--_Trans._ + + +WINE. + +The most common adulteration to which wines are subjected is the +addition of water: wines having a rich color are frequently mixed by the +dealer with lighter wines, and the fraud consummated by adding water. +The detection of this adulteration is somewhat difficult, as water is a +normal constituent of wine. In Paris the following method is usually +employed: As soon as the wine is confiscated, it is ascertained what +kinds of wine are manufactured by the inculpated dealer, and a statement +obtained from him, giving the proportions of alcohol, etc., contained in +the various brands. A wine is then prepared, according to the +information received, an estimation of the alcohol contained in the +prepared sample made, and the results compared with those furnished by a +similar examination of the suspected wine. In case the proportion of +alcohol is less in the suspected wine than in the prepared sample, it is +evident that a fraudulent adulteration has been committed. If, however, +the quantity of alcohol is the same in both wines, it does not +necessarily follow that the wine has escaped admixture, since this body +may have been added after the adulteration with water. In addition to +the estimation of alcohol, it is also necessary to determine the amount +of cream of tartar (bitartrate of potassa) present, as the proportion of +this salt would be sensibly decreased by the addition of alcohol and +water to the wine. This fraud could, however, be disguised by +subsequently adding the proper amount of cream of tartar. + +It is also well to ascertain if two equal quantities of the prepared +sample and the wine under examination require the same amount of +solution of hypochlorite of lime for decolorization. In case the +suspected wine has been adulterated, the quantity of hypochlorite +solution used will be less than the amount necessary to decolorize the +prepared wine. Foreign coloring matter may be added by the adulterator, +but this fraud is easily detected by adding potassa to the sample: if +its coloration is natural, a green tint is produced; whereas, if foreign +matter has been introduced, the wine assumes various other colors upon +the addition of the alkali.[V] + + [V] _Cotlini_ (_Ann. du genie civil_, No. 3, 1873) states that the + following reactions occur when artificially colored wines are heated + with potassa: + + Pure wine no precipitate greenish hue + Elderberry violet " + Beet-sugar red " + Logwood red violet-red " + Privet violet-blue " + Turmeric light-blue " + + According to _M. de Cherville_ (_Quar. Jour. Sc._), a bright violet + coloration is produced in the above test, if litmus be present. + + Fuchsin is separated by treatment with subacetate of lead and + addition of amylic alcohol (_Jour. de Ph. et de Ch. Mar. + 1873_).--_Trans._ + +The indications furnished by the above test are rendered valueless, if +the wine has been artificially colored by the addition of the coloring +matter of grape-skins; but the execution of this fraud would require +some knowledge of chemistry, and fortunately adulterators, as a class, +are deficient in this branch of science. + +Another method for detecting the addition of water is based upon the +fact that fermented liquors do not contain air in solution, but only +carbonic acid; whereas, water dissolves oxygen and nitrogen. It is +executed as follows: + +The wine to be tested is placed in a flask, the delivery-tube of which +is also filled, and heated; the evolved gas being collected in a tube +filled with mercury. In case the wine is pure, the disengaged gas will +be completely absorbed by potassa; if, on the other hand, water has been +added, an unabsorbed residue, consisting of oxygen and nitrogen, will +remain. + +This test is useless in case water, through which a current of carbonic +acid gas has been passed for a considerable time, has been employed. +Under these circumstances, however, the presence of the gas would +probably be detected by the taste of the wine, as well as by the +estimation just mentioned, since the sample would invariably contain a +larger proportion of the gas than the standard with which it is +compared; indeed, it would be almost impossible to prepare a solution +which contained exactly the proportion of carbonic acid ordinarily +present in wine. + +It remains to mention the methods employed in determining the amount of +alcohol and cream of tartar contained in wine. + +The alcometrical method usually employed is based upon the difference in +density possessed by pure alcohol and by mixtures of alcohol and water. +_Gay-Lussac_ has proposed an areometer (_alcoholmeter_), provided with a +scale which directly indicates the proportion of alcohol contained in a +mixture. As the indications furnished by this instrument vary with the +temperature, and the scale is constructed on the basis of a temperature +of 15°, a correction of the results obtained is necessary if the +determination is made at other temperatures. Gay-Lussac has compiled a +table which indicates at once the required correction; the following +formula can also be used: _x = c ± 0.4 t_, where _x_ is the quantity of +alcohol present in the sample; _c_ the degree indicated by the +alcoholmeter, and _t_ the number of degrees differing from the +temperature of 15°: the second member of the formula is subtracted from, +or added to the first, as the temperature at which the estimation is +made is greater or less than 15°.[W] + + [W] Tralles alcoholmeter is almost exclusively employed in this + country.--_Trans._ + +In case the wine to be examined contains substances other than water +and alcohol, which would affect its density, it is necessary, before +making use of the alcoholmeter, to distil the sample and subsequently +examine the distillate, which will consist of a simple mixture of water +and alcohol. Usually the distillation is discontinued as soon as +one-third of the sample has passed over, and a quantity of distilled +water, sufficient to render the volume of the mixture equal to the +original volume of the wine, added to the distillate: the fluid +remaining in the flask will be entirely free from alcohol. The addition +of water to the distillate is not indispensable, but otherwise it is +necessary to divide the degrees indicated by the alcoholmeter by 3, in +order to reduce the result to the original volume of the wine taken. + +_M. Salleron_ offers for sale a small apparatus (Fig. 20) used in +examinations of this character, consisting of a flask, closed with a +gutta-percha cork, containing a tube which connects with a worm passing +through a cooler. The flask is supported by an iron stand, and heated +with a gas or spirit lamp. + + [Illustration: Fig. 20.] + +In order to estimate the cream of tartar, the wine is evaporated to the +consistency of an extract, alcohol of 82° B. added, and the residue +obtained calcined in a crucible. The amount of salt present in the fused +mass is then determined by the alkalimetric method, as directed in all +works on quantitative analysis. The carbonate obtained from 1 gr. of +cream of tartar exactly saturates 9.75 cubic centimetres of a solution +containing 100 grammes of sulphuric acid of 66° B., and 1800 grammes of +distilled water. + +The detection of toxical substances, often contained in wine, is +accomplished by the methods described under the head of detection of +poisons. + + +VINEGAR. + +Vinegar is frequently adulterated with water, and occasionally sulphuric +acid is added to artificially increase its acidity. + +The ordinary reagents--such as chloride of barium, or nitrate of +silver--are not adapted to the direct detection of sulphuric acid, or of +other mineral acids, as sulphates and chlorides, which are as readily +precipitated as the free acids, may also be present. + +The following method, proposed by _M. Payen_, is usually employed: + +Five centigrammes of starch (fecula) are added to a decilitre of table +vinegar, the mixture boiled for 12 or 15 minutes, and, after the fluid +has become _completely cooled_, a few drops of iodine solution added: +dilute acetic acid does not affect starch, and, in case the vinegar is +pure, a blue coloration is produced; if, on the other hand, even a +minute quantity of a mineral acid be present, the starch is converted +into dextrine, and the addition of iodine fails to cause a blue +coloration. + +The water present is indirectly estimated by determining the amount of +acetic acid contained in the vinegar. This can be accomplished in +different ways: either the quantity of a standard solution of an alkali, +necessary to exactly neutralize a measured quantity of the vinegar, is +ascertained, or the vinegar is supersaturated with solution of baryta, +the excess of the salt eliminated by conducting carbonic acid through +the fluid, the precipitate removed by filtration, and the baryta salt in +the filtrate precipitated by the addition of sulphuric acid. The second +precipitate is then collected on a filter, washed, weighed, and the +amount of acetic acid present calculated: this is done by multiplying +its weight by 0.515. + + +SULPHATE OF QUININE. + +Owing to the high price of this salt, it is frequently adulterated. The +substances used for this purpose are: crystalline sulphate of lime, +boric acid, mannite, sugar, starch, salicine, stearic acid, and the +sulphates of cinchonine and quinidine. These bodies are detected as +follows: + +_a._ Upon slightly warming 2 grammes of sulphate of quinine with 120 +grammes of alcohol of 21° B., the pure salt completely dissolves; if, +however, starch, magnesia, mineral salts, or various other foreign +substances are present, they are left as insoluble residues. + +_b._ Those mineral substances that are soluble in alcohol are detected +by calcining the suspected sample: pure sulphate of quinine is +completely consumed; whereas, the mineral substances present remain +behind as a residue. + +_c._ In presence of salicine, the salt acquires a deep red color, when +treated with concentrated sulphuric acid. + +_d._ Stearic acid remains undissolved upon treating sulphate of quinine +with acidulated water. + +_e._ To detect sugar and mannite, the sample is dissolved in acidulated +water, and an excess of hydrate of baryta added: a precipitate, +consisting of quinine and sulphate of baryta, is produced. Carbonic acid +is then passed through the fluid, in order to precipitate the excess of +baryta as insoluble carbonate, the fluid saturated with ammonia, to +throw down the quinine which may have been re-dissolved by the carbonic +acid, and the mixture filtered. If the salt be pure, no residue will be +obtained upon evaporating the filtrate; a residue of sugar or mannite is +formed, if these substances are present. + +_f._ Sulphate of quinine invariably contains 2 or 3 per cent. of +cinchonine, originating, not from a fraudulent admixture, but from an +incomplete purification of the salt. One of the best methods for +detecting the respective quantities of quinine and cinchonine, present +in a sample of the sulphate, is the following: Several grammes of +ammonia and ether (which has previously been washed with water) are +added to one or two grammes of the salt under examination, the mixture +thoroughly agitated, and then allowed to remain at rest. The supernatant +etherial solution contains all of the quinine; the cinchonine, which is +almost completely insoluble, both in water and ether, remaining +suspended between the layers of the two fluids. The ether is next +removed by means of a stop-cock funnel, evaporated to dryness, and the +weight of the residue obtained determined. The operation is then +repeated, the ether being replaced by chloroform in which both quinine +and cinchonine are soluble. The residue, formed by the evaporation of +the second solution, will be heavier than the first residue: the +difference between the two weighings gives the weight of the cinchonine +present. + +_g._ The detection of the presence of sulphate of quinidine is based +upon the difference in the solubilities of the oxalates of quinine and +quinidine. Oxalate of quinidine is sufficiently soluble in cold water +not to be precipitated by double decomposition when solutions of oxalate +of ammonia and sulphate of quinidine are mixed. Under the same +circumstances, quinine is almost completely thrown down. The test is +applied as follows: + +The suspected salt is dissolved in water, a slight excess of oxalate of +ammonia added, and the precipitate formed separated by filtration. If +the salt be pure, the filtrate is scarcely rendered turbid by the +addition of ammonia; when, however, sulphate of quinidine is present, it +will be entirely contained in the filtrate, in which ammonia will +produce an abundant precipitate. + + +EXAMINATION OF BLOOD STAINS. + +This branch of legal chemistry formerly gave but very unreliable +results. It is scarcely ten years since the reactions that are now +regarded as only secondary and confirmative in their character, and far +from conclusive, were the only ones in use: these are the tests based +upon the presence of iron and albumen in the blood. Since then, great +progress has been made in the methods employed. It must not be +understood, however, that the question under consideration always admits +of an easy and decisive solution: the stains are sometimes too greatly +altered to be identified; but in cases where the distinctive reactions +of blood can be produced, the real nature of the stains under +examination can, at present, be determined with certainty. + +The tests more recently introduced consist in the production of small +characteristic crystals, termed _haemin_ crystals, and in the use of the +spectroscope. Crystals of haemin (first discovered by _Teichman_) are +formed when dry blood is dissolved in concentrated acetic acid, and the +solution evaporated to dryness: they are of a brownish-red color. +_Brücke_ first suggested an analytical method, based upon this property +of blood, which is equally characteristic and sensitive: It is only +necessary to dissolve a minute portion of the matter to be examined +(dried blood, or the residue left by the evaporation of the fluid +obtained by treating the stain, or the dried blood, with cold water) in +glacial acetic acid and evaporate the solution to dryness in order to +obtain crystals of haemin, which can be readily recognized by means of a +microscope having a magnifying power of 300 diameters. If the crystals +originate from fresh blood, they appear as represented in Fig. 21; +crystals from old blood are represented in Fig. 22. + + [Illustration: Fig. 21.] + + [Illustration: Fig. 22.] + +The former possess a reddish-brown, the latter a lighter color. + +The various methods now employed to produce haemin crystals were +proposed by _Hoppe-Seyler_, by _Brücke_ and by _Erdman_. Whichever +process is used, the suspected stains are at first carefully separated +from the material upon which they are deposited. If they are present on +linen, or other fabrics, the stained portions, which always remain +somewhat stiff, are cut off: they will present a reddish-brown color, in +case the cloth is not dyed: if the stains are on wood, they are removed +by means of a sharp knife; if on stone or iron, they are detached by +scraping. + +In case Hoppe-Seyler's method is used, the stains, separated as +directed above, are macerated with a little _cold_ water (warm water +would coagulate the albumen present, and consequently prevent solution +taking place): the stains become soft, striae and brown or reddish +clouds are observed, especially when the dried blood is fresh, and, at +the same time, the objects upon which the stains were deposited are +decolorized. Upon allowing the fluid obtained in this way to +spontaneously evaporate on a watch-glass, a reddish brown or brownish +residue is left, from which the crystals of haemin are prepared in the +following manner: An almost imperceptible amount of common salt is added +to the residue, then, six to eight drops of concentrated acetic acid, +and the mass thoroughly mixed by stirring with a small glass rod. The +mixture is at first heated over a small gas flame, then evaporated to +dryness by the heat of a water-bath. If the stains were produced by +blood, a microscopic examination of the residue will reveal the presence +of haemin crystals. This method presents an objection: if the stained +objects have been washed with warm water previously to the examination, +the albumen will be coagulated, and the blood rendered insoluble; in +this case, cold water will fail to dissolve anything, and the residue +will not produce crystals when treated with acetic acid. + +In order to remedy this difficulty Brücke operates directly upon the +stained woven or ligneous fibre, or the matter removed from the stone or +iron: The materials are boiled in a test-tube with glacial acetic acid, +the fluid decanted or filtered, a trace of common salt added, and the +liquid then evaporated on a watch-glass at a temperature between 40 and +80°. If the stains really originated from blood, haemin crystals will +now be easily perceptible upon examining the residue obtained under the +microscope. + +The stained fabric, the matter removed from the stone or iron, or the +residue left by the solution with which the stains have been treated, is +placed on the glass, a trace of chloride of sodium added, and the whole +covered with a thin glass plate. A drop of acetic acid is then placed at +the edge of the plates--between which it is soon introduced by capillary +attraction--and the mixture allowed to rest in the cold for a few +moments. The mass is next brought into solution by slightly heating, and +is then evaporated by holding the plate at a considerable distance above +a gas burner. The fluid is examined from time to time under the +microscope: when it is sufficiently concentrated, crystals, presenting +the appearance represented in Figs. 21 or 22, will be observed. These +are especially well-defined, if an insoluble substance is also present +between the plates--which prevents their adhering. The fluid collects by +capillary attraction at the points of contact of the plates as a more or +less colored layer, in which the crystals are deposited. + +Should the above test fail to present distinctive indications at first, +one or two fresh drops of acetic acid are introduced between the plates, +and the examination is repeated. The result is not to be regarded as +negative, until several trials have proved fruitless, as the stained +portions are but slowly soluble, and crystallization may have been +prevented by the too rapid evaporation of the acetic solution. + +Haemin crystals, once seen, can hardly be confounded with other +substances; still, it is well to identify them by confirming their +insolubility in water, alcohol, and cold acetic acid, as well as their +instantaneous solubility in soda lye. + +The addition of common salt is ordinarily superfluous, as it is +normally contained in the blood; but it is possible, if the stains were +washed with warm water, that, in addition to the coagulation of the +albumen, the solution of the salt may have taken place, in which case +crystals will fail to form. The addition of salt is to remedy this +possible contingency; albeit, the delicacy of the test is not affected, +even if crystals of chloride of sodium are produced, as these are easily +soluble in water, and are readily distinguished from those of haemin by +aid of the microscope. + +The indications furnished by means of the spectroscope are less reliable +than those given by the production of haemin crystals; moreover, the +spectroscopic examination requires favorable weather for its execution. +Still, the test should be employed in all possible instances. The course +pursued is the following: + +The aqueous fluid, with which the stains have been treated, is placed in +a watch glass, and evaporated _in vacuo_ over sulphuric acid; the last +remaining portion of the fluid being united in the bottom of the glass +by causing it to collect in a single drop. When the evaporation of fluid +is completed, the watch-glass is placed before the narrowed slit of a +spectroscope, and a ray of diffused light (or better, light reflected +from a heliostat) made to pass through the part of the glass containing +the residue. If the stains originate from blood, the absorption lines of +_haemoglobin_, consisting of two large dark bands, to the right of the +sodium line (_Frauenhofer's_ line D), will be observed in the spectrum. +In case both of the above tests fail to give positive results, it is +almost certain that the stains examined were not caused by blood. If, on +the contrary, the reactions were produced, scarcely any doubt exists as +to the presence of blood. Under these circumstances it is advisable to +confirm the results by means of the tests that have been previously +spoken of as being formerly exclusively employed; these are the +following: + +_a._ 1/2 to 1 c. c. of ozonized oil of turpentine, _i. e._ turpentine +which has been exposed to the air sufficiently long to acquire the +property of decolorizing water that is slightly tinted with indigo--is +introduced in a test-tube, and an equal volume of tincture of guaiacum +added (the latter tincture is prepared by treating an inner portion of +the resin with alcohol, until its brownish color is changed to a +brownish-yellow). + +If upon adding some of the substance under examination to the above +mixture a clear blue coloration ensues, and the insoluble matter thrown +down possesses a deep blue color, the presence of coloring matter of the +blood is indicated. The mixture also imparts a blue color to moistened +spots from which the blood stains have been as completely extracted as +possible. Unfortunately sulphate of iron gives the same reaction.[X] + + [X] Fresh gluten, gum arabic, and caseine also cause the blue + coloration.--_Trans._ + +_b._ Upon heating the fluid obtained by treating the stains with cold +water in a test-tube, its brown or reddish color disappears, and +greyish-white flakes of coagulated albumen are thrown down. The +precipitate acquires a brick-red color, when treated with an acid +solution of nitrate of mercury containing nitrous acid. The albumen is +also coagulated by the addition of nitric acid: it assumes a more or +less yellow color, if heated with a slight excess of the acid. +Chlorine-water, especially upon heating, likewise precipitates albumen +in the form of white flakes. + +_c._ If the fluid is acidulated with a few drops of acetic acid, and a +drop of ferrocyanide of potassium added, a white precipitate, or, at +least, turbidity is produced. + +_d._ The flakes of albumen, separated by heating, dissolve in caustic +alkalies to a solution, from which they are re-precipitated by nitric +acid, or chlorine water. + +_e._ Upon treating blood stains with chlorine-water, a solution which +contains chloride of iron, and acquires a red coloration by the addition +of sulphocyanide of potassium, is formed. + +_f._ Should the stains have failed to be affected by cold water (which, +as has already been remarked, is the case when they have been previously +washed with hot water), they are treated with weak soda lye. Nitric +acid, hydrochloric acid, and chlorine water will produce in the solution +so obtained a white precipitate, which exhibits the general properties +of albumen previously described. In case the stains are deposited upon +linen, it is necessary to replace the soda by ammonia, in order to avoid +dissolving the fabric. + +_g._ Solutions of the alkalies, which dissolve the albumen, leave the +coloring matters intact, and consequently do not decolorize the fabric. +If the latter is afterwards subjected to the action of hydrochloric +acid, the coloring matter is dissolved, forming a solution that leaves +upon evaporation to dryness a residue containing iron, which gives a +blue coloration with ferrocyanide of potassium, and a red coloration +with sulphocyanide of potassium. + +_h._ The coloring matter of blood dissolves in boiling alcohol, to which +sulphuric acid has been added, to a brown dichroic fluid (appearing +green by transmitted light, and red by reflected light). A mixture of +rust and blood exhibits the same phenomenon. + +_i._ If substances containing blood are heated in a dry tube, an odor +resembling that of burnt horn is emitted. In case the stained fabric is +a substance that would produce this odor, (such as wool, silk, or hair), +the test naturally loses all value. + +_j._ If the fluid obtained by treating the stains either with water or +alkali is evaporated with a little carbonate of potassa, and the residue +heated, at first at 100°, then to redness, in a glass tube to which a +fresh quantity of carbonate of potassa has been added, cyanide of +potassium is formed. When cold, the tube is cut above the part +containing the fused mixture, the mass heated with iron-filings and +water, the fluid filtered, and the filtrate then acidulated with +hydrochloric acid: ferrocyanide of potassium will be present in the +fluid, and upon adding a drop of solution of perchloride of iron a +green, or blue, color will be produced, and a precipitate of Prussian +blue gradually thrown down. + +If the stained cloth is non-nitrogenous (_per ex._: hemp, linen, or +cotton), instead of treating it with water, it may be heated until +pulverulent, mixed with carbonate of potassa, the mixture calcined, and +the operation then completed as just described. This test having given +affirmative results, the operations should be repeated with an unstained +portion of the cloth, to remove all doubt that the indications obtained +do not really originate from the fabric. + +In the present state of science, it is impossible to discriminate +chemically between human and animal blood. _M. Barruel_, it is true, is +able, not only to accomplish this, but also to distinguish the blood of +the various species of animals by its odor! But this test has a somewhat +hypothetical value for scientific purposes. In regard to the crystals of +haemin, they do not present sufficient difference to allow the blood of +different animals to be distinguished. We have not yet treated of the +globules. It often occurs that these minute organs are so altered as to +be no longer recognized in the microscopic examination; when, however, +the stains are tolerably recent, they may be detected by examining the +moistened stained cloth, directly under the microscope: a discrimination +between animal and human blood is then possible: corpuscules of human +blood possess the greater size: those of the sheep, for instance, have +only one-half the diameter of the former. It is, however, but seldom +that this distinction can be made use of.[Y] + + [Y] _Menstrual blood_ is recognized by the presence of epithelial + cells.--_Trans._ + + +EXAMINATION OF SPERMATIC STAINS. + +In cases where attempt at violence, rape or pederasty is suspected, the +expert may be required to determine the nature of stains found on +clothing, sheets, etc. The fact that the stains were produced by semen, +may often be regarded, _per se_, as criminating evidence. This class of +investigation possesses, therefore, considerable importance. + +_External appearance of the stains._--Dry spermatic stains are thin, and +exhibit a greyish or, occasionally, a citron-yellow color, if present on +white cloth. In case the fabric is colored, they appear whitish and, if +on linen, present a glossy aspect. They are translucid, when observed by +transmitted light. If the fabric, upon which the stains are deposited, +is of a heavy texture, they are visible only on one side: under all +circumstances, their circumference is irregular and undulated. These +indications, however, are not conclusive, but vary according to whether +the stains were produced by the thick semen of a vigorous man, or the +aqueous seminal fluid of an aged and diseased person, or by semen more +or less mixed with the prostatic fluid. Upon moistening spermatic +stains, the distinctive stale odor of fresh semen is sometimes emitted, +but this characteristic is usually obscured by the presence of foreign +substances. + +Semen stains are soluble in water, forming a gummy fluid, in which +chlorine, alcohol, bichloride of mercury, acetate and subacetate of lead +produce a white precipitate, but which fails to be coagulated by +heating. Plumbate of potassa does not impart a fawn-color to these +stains, at a temperature above 20°, as is the case with those produced +by albuminous substances. + +Persulphate of iron imparts to spermatic stains a pale yellow color, + +Sulphate of copper, a bluish grey color, + +Cupro-potassic tartrate, a bluish grey color, + +Nitrate of silver, a pale grey color, + +Nitric acid, a pale yellow color. + +The above reactions, separate or united, are insufficient; they are not +very delicate, and are likewise produced by stains originating from the +other varieties of mucus: the indications furnished by a microscopic +examination of the stains are alone conclusive. + +_Microscopic examination._--Semen contains as its principal and +fecundating constituent, peculiar vibratory filaments, (_spermatozoa_), +held suspended in a viscous fluid. These filaments, when preserved in a +warm and moist place, retain their activity for a considerable time: it +is even possible that they may exhibit vitality in the organs, into +which they have been voluntarily or forcibly ejaculated, for ten, or +even twenty-four hours. When exposed to cold air, the spermatozoa +quickly expire; still, they preserve their form for some time, and, as +this is very characteristic, it is then easy to identify them; moreover, +since they originate exclusively in the testicles, their detection may +be considered as certain evidence of the presence of semen. In stains +produced by aged persons, and by persons enfeebled by excesses, the +spermatozoa fail to be presented; in case they are discovered, this fact +evidently does not affect the certainty of the spermatic origin of the +stains. The contrary conclusion is never absolutely certain: still, if +the use of the microscope fails to establish the presence of +spermatozoa, it is almost certain that the stains were not produced by +semen. + +Of the various methods for obtaining from the stains a preparation +adapted to the microscopic examination, the one proposed by M. Charles +Robin is the most simple and reliable. + +A strip, 1 c. c. in size (comprising the entire stain, if this be small, +containing its inner portion, if it be large), is cut from the fabric +under examination, care being taken that the two extremities of the +sample extend beyond the stained portion. + +One end of the cloth is then immersed in a capsule, or watch-glass, +containing pure water: the stains become moistened by capillary +attraction, and, in a space of time varying from twenty minutes to two +hours, acquire the appearance of fresh semen. As soon as the stained +portion becomes swollen and softened, the surface of the cloth is gently +scraped with a spatula, and the substance removed placed on the slide of +the microscope. The particles are next slightly detached, a drop of +water added, if necessary, and the whole covered with a small plate of +very thin glass. The preparation is then examined by a microscope, +having a magnifying power of from 500 to 600 diameters. In this way, the +presence of either entire or broken spermatozoa is readily detected. +Their existence is rendered still more apparent, if the mucus present is +dissolved by adding a drop of acetic acid to the preparation. + +Entire spermatozoa consist of long slender filaments, having a length +of 0.04041 to 0.04512 millimetre; the anterior extremity presents an +oval enlargement, either round or pyriform, exhibiting a double outline, +when magnified to 500 diameters. This enlarged end is termed the "head;" +the entire remaining portion being regarded as the "tail." In case the +spermatozoa are broken, they are severed either near the head or in the +middle of the tail, and a mass of detached fragments will be observed in +the microscopic examination. The spermatozoa are not the only +corpuscules revealed by the microscope; other substances, entirely +different in character, are often observed. Although the detection of +these bodies is, in itself, of no value, it will be well to enumerate +and characterize them; they are: + +_a._ Oily globules. + +_b._ Leucocytes, or spherical and finely granulous globules of mucus. + +_c._ Corpuscules, originating from the seminal vesicles, termed +sympexions. These are rounded or ovoid, possess an irregular outline, +and are usually mixed with the spermatozoa and globules of mucus. + +_d._ Crystals of phosphate of magnesia, varying greatly in size; the +largest are from 0.mm. 001 to 0.mm. 002 in length. The crystals formed +upon cooling the semen, present the form of an oblique prism, with a +rhomboidal base. Occasionally they are elongated and flattened; they +then assume the form of a rhomboid. + +_e._ Epithelial cells; originating from the mucous follicles of the +urethra. + +_f._ Irregular grains of dust; soluble in acetic and hydrochloric acids, +with gaseous evolution. + +_g._ Brownish-red grains of rust; only slightly soluble in acetic acid, +but easily soluble in hydrochloric acid. + +_h._ Filaments of the strained fabric; detected by their texture, and +general appearance. + +_i._ Grains of starch, in case the cloth has been stiffened. These are +almost invariably swollen, and are frequently broken and deformed. + +If the examination is to be secretly executed, and the cloth cannot +well be cut, it is rolled in a cone, in such a way that the external +side contains the stained portion. The lower extremity of the cone +(which should be free from stains) is dipped in a watch-glass containing +water, so as to avoid directly wetting the stains. The cone soon becomes +moistened by absorption, and the operation is then completed in the same +manner as when the fabric has been cut; which is always preferable, when +possible. + +The examination of spermatic stains consists, then, in moistening the +stains with water, separating them as completely as possible from the +stained cloth, and determining the presence of the spermatozoa by means +of the microscope. + +All other tests are valueless; even their execution for confirmatory +purposes is not advisable; inasmuch as they fail to possess a +distinctive character, and the reagents employed in their production may +destroy the fabric, and thus prevent the formation of the only +conclusive reaction--the detection of the spermatozoa. + +In case the stains are deposited upon a woman's chemise, they are +usually present on both the front and back portions, and are sometimes +to be found on the sleeves. When a man's shirt is under examination, +especial attention should be given to the anterior portions. The +pantaloons are also often stained; usually in the interior, but +sometimes also on the exterior, just above the thighs. In reporting the +decision to the court, as to the nature of the stains, their precise +position should invariably be stated, as, by this means, the +circumstances attending the commission of the crime may be, at least +partially, elucidated. + + + THE END. + + + + +APPENDIX. + + +The following list of the literature of toxicology, and its allied +branches, will, it is hoped, be of service to those readers who are +desirous of obtaining further information on the subjects treated in +this work.--_Trans._ + + +BOOKS. + + *Accum*; A treatise on adulteration of food, and culinary poisons. + London, 1822. + + *Adrien*; Recherches sur le lait au point de vue de sa composition, de + son analyse, de ses falsifications et surtout de + l'approvisionnement de Paris. Paris, 1859. + + *Angell and Hehner*; Butter; its analysis and adulterations. + London, 1874. + + *Anglada*; Traité de toxicologie. Paris, 1835. + + *Atcherly*; Adulteration of food. London, 1874. + + *Bandein*; Die Gifte und ihre Gegengifte. Basel, 1869. + + *Beck*; Elements of medical jurisprudence. Albany, 1851. + + *Bellini*; Lezionis perementali di Tossicologia. Firenze, 1865. + + *Bergman*; Zur Kentniss der putriden Gifte. Dorpat, 1868. + + *Bernard*; Leçons sur les substances toxiques. Paris, 1857. + + *Billard*; Considerations medico-légale sur les empoisonnements par + les irritants. Paris, 1821. + + *Blondlot*; Sur la recherche de l'arsenic par la methode de Marsh. + Nancy, 1857. + + _Ibid_; Sur la recherche toxicologique du phosphore par la coloration + de la flamme. Nancy, 1861. + + _Ibid_; Sur le dosage de l'antimoine dans les recherches + toxicologiques. Nancy, 1865. + + *Boettcher*; Ueber Blutkrystalle. Dorpat, 1862. + + *Bonsels*; Ein Beitrag zur Analyse des Arsens, vorzugsweise in + gerichtlichen Fällen. Kiel, 1874. + + *Borie*; Catechisme toxicologique. Tuelle, 1841. + + *Bouchardt et Quevenne*; Du lait. Paris, 1857. + + *Bowman and Bloxam*; Medical chemistry. London, 1874. + + + *Briand et Chaudé*; Manuel complet de médicine légale; contenant un + manuel de chimie légale. Paris, 1873. + + *Buchner*; Toxikologie. Nüremburg, 1859. + + *Bureaux*; Histoire des falsifications des substances alimentaires. + Paris, 1855. + + *Chapman*; Manual of Toxicology. London, 1853. + + *Chatin*; Recherches experimentals et considerations sur quelques + princips de la toxicologie. Paris, 1844. + + *Chiaje*; Tossicologia. Napoli, 1835. + + *Chaussier*; Médicine légale. Paris, 1858. + + *Chevalier*; Dictionaire des alterations et falsifications des + substances alimentaires, médicamenteuses et commerciales, avec + l'indication des moyens de les reconnaitre. Paris, 1856. + + _Ibid_; Essais practiques sur l'examen chimique des vins, considéré + sous la rapport judiciaire. Paris, 1857. + + *Christison*; A treatise on poisons. Edinburg, 1836. + + *Collier*; Paradoxology of poisoning. London, 1856. + + *Cooper*; Tracts on medical jurisprudence. Phila., 1819. + + *Cormenin*; Memoire sur l'empoisonnement par l'arsenic. Paris, 1842. + + *Cotter*; Adulteration of liquors. N. Y., 1874. + + *Cottereau*; Des alterations et des falsifications du vin, et des + moyens physiques et chimiques employés pour les reconnaitre. + Paris, 1851. + + *Cox*; Poisons; their effects, tests and antidotes. London, 1852. + + *Culbrush*; Lectures on the adulteration of food, and culinary + poisons. Newburg, 1823. + + *Dalton*; Adulteration of food. London, 1857. + + *Divergie*; Médicine légale. Paris, 1852. + + *Dragendorff*; Beiträge zur gerichtlichen Chemie einzelner organischen + Gifte. St. Petersburg, 1872. + + _Ibid_; Untersuchungen aus dem pharmaceutischen Institut in Dorpat. + St. Petersburg, 1872. + + _Ibid_; Manuel de toxicologie; traduit par E. Ritter. Paris, 1873. + + *Druitt*; On wines. London, 1866. + + *Duflos*; Die wichtigsten Lebenbedürfnisse, ihre Aechtheit und Güte; + Verunreinigungen, Verfälschungen, etc. Breslau, 1846. + + _Ibid_; Die Prüfung chemischer Gifte. Breslau, 1871. + + _Ibid_; Handbuch der angewandten gerichtlich-chemischen Analyse der + chemischen Gifte; ihre Erkennung in reinem Zustand und in + Gemischen betreffend. Leipzig, 1873. + + *Duflos u. Hirsch*; Das Arsen; seine Erscheinung, u. s. w. + Breslau, 1842. + + *Dupasquier*; Consultation medico-légale relative à une accusation + d'empoisonnement par le plomb. Lyon, 1843. + + *Erhard*; Die giftigen pflanzenalkaloiden und deren Ausmittelung auf + mikroskopischem Wege. Passau, 1867. + + *Eulenberg*; Die Lehre von den schädlichen und giftigen Gasen. + Braunschweig, 1849. + + *Flandin*; Traité des poisons. Paris, 1852. + + *Flandin et Danger*; De l'arsenic. Paris, 1853. + + *Fop*; Adulteration of food. London, 1855. + + *Fraise*; Alimentation publique; le lait, ses falsifications, etc. + Nancy, 1864. + + *Frank*; Manuel de toxicologie; traduit de l'allemand par Vrankan. + Anvers, 1803. + + *Fresenius*; Auffindung unorganischen Gifte in Speisen, u. s. w. + Braunschweig, 1856. + + *Friedrich*; Die Verfälschung der Speisen und Getränke. Münster, 1859. + + *Galtier*; Traité de toxicologie. Paris, 1855. + + *Galtier de Claubry*; De la recherche des alcalis organiques dans les + cas d'empoisonnement. Paris, 1862. + + *Ganeau*; Alterations et falsifications des farines. Lille, 1856. + + *Garnier*; Des falsification des substances alimentaires et des moyens + de les reconnaitre. Paris, 1844. + + *Gerhardt*; Précis d'analyse pour la recherche des alterations et + falsifications des produits chimiques et pharmaceutiques. + Paris, 1860. + + *Garland*; Précis d'analyse chemique qualitative. Paris, 1855. + + *Gmelin*; Allgemeine Geschichte der thierischen und mineralischen + Gifte. Erfurt, 1806. + + *Gorup-Besanez*; Anleitung zur qualitativen und quantitativen + zoochemischen Analyse. Braunschweig, 1871. + + *Gosse*; Des taches, au point de vue medico-légale. Paris, 1862. + + *Griffin*; The chemical testing of wines and spirits. London, 1872. + + *Griffith and Taylor*; A practical manual of the general, chemical, + and microscopical character of the blood, etc. London, 1843. + + *Guerin*; Nouvelle toxicologie. Paris, 1826. + + *Guy*; Principles of forensic medicine. London, 1843. + + *Gwosden*; Ueber die Darstellung des Hämin aus dem Blut und den + qualitativen Nachweis minimaler Blutmengen. Wien, 1866. + + *Hager*; Untersuchungen. Leipzig, 1873. + + *Hartung-Schwarzkoff*; Chemie der organischen Alkalien. München, 1855. + + *Hassall*; Adulteration of food. London, 1855. + + *Van Hassett*; Handbuch der Giftlehre. Braunschweig, 1862. + + *Helwig*; Das mikroskop in der Toxikologie. Mainz, 1864. + + *Herman*; Lehrbuch der experimentellen Toxikologie. Berlin, 1875. + + *Hitzig*; Studien über Bleivergiftung. Berlin, 1870. + + *Hoffman*; Manual of chemical analysis. N. Y., 1873. + + *Hoppe-Seyler*; Handbuch der physiologisch und pathologisch chemischen + Analyse. Berlin, 1870. + + _Ibid_; Medicinisch-chemische Untersuchungen. Berlin, 1871. + + *Horsley*; The toxicologist's Guide. London, 1866. + + *How*; Adulteration of food and drink. London, 1855. + + *Huseman*; Handbuch der Toxikologie. Berlin, 1870. + + *Jaillard*; De la toxicologie du bichromate de potasse. + Strasbourg, 1861. + + *Jones (H. Bence)*; Chemistry of wines. London, 1874. + + *Klincke*; Die Verfälschung der Nahrungsmittel, Getränke, etc. + Leipzig, 1858. + + *v. Kupffer*; Handbuch der Alkoholometrie. Wien, 1866. + + *de Lapparent*; Les moyens de constater la pureté des principales + huiles fixes. Cherbourg, 1855. + + *Lefort*; Etudes chimiques et toxicologiques sur la morphine. + Paris, 1861. + + *Legrand*; Traité de médicine légale et de jurisprudence médical. + Paris, 1873. + + *Letheby*; On food. N. Y., 1872. + + *Lerwin*; Toxikologischen Tabellen. Berlin, 1856. + + *Liebreich*; Outlines of Toxicology. London, 1875. + + *Lindes*; Beiträge zur gerichtlichen Chemie. Berlin, 1852. + + *Lunel*; Guide pratique pour reconnaïtre les falsifications et + alterations des substances alimentaires. Paris, 1874. + + *Malle*; Essai d'analyse toxique génerale. Strasbourg, 1838. + + *Marset*; Composition, adulteration, and analysis of food. + London, 1856. + + *Marshall*; Remarks on arsenic. London, 1817. + + *Marx*; Geschichtlich Darstellung der Giftlehre. Göttingen, 1829. + + *Mata*; Tratado de medicina y cirugia legal. Paris, 1874. + + *Mayercon and Bergeret*; Recherches sur la passage de l'arsenic et de + l'antimoine dans les tissus et les humeurs. Paris, 1874. + + *Meissner*; Aräometrie in ihrer Anwendung auf Chemie und Technik. + Wien, 1816. + + *Mitchell*; Falsification of food. London, 1848. + + *Mohr*; Chemische Toxikologie. Braunschweig, 1874. + + *Monier*; Memoires sur l'analyse de la lait et des farines. + Paris, 1858. + + *Montgarney*; Essai de toxicologie. Paris, 1818. + + *Muller*; Anleitung zur Prüfung der Kuhmilch. Bern, 1858. + + *Münk und Leyden*; Phosphorvergiftung. Berlin, 1865. + + *Neubauer*; Chemie des Weines. Wiesbaden, 1874. + + *Neuman*; Die Erkennung des Bluts bei gerichtlichen Untersuchungen. + Leipzig, 1869. + + *Normandy*; The commercial hand-book of chemical analysis. + London, 1875. + + *Odling*; A course of practical chemistry. London, 1872. + + *Oesterlen*; Das menschliche Haar und seine gerichtärtliche Bedeutung. + Tübingen, 1875. + + *Orfila*; Rapport sur les moyens de constater la presence de l'arsenic + dans les empoisonnements par ce toxique. Paris, 1841. + + _Ibid_; Traité de médicine légale. Paris, 1848. + + _Ibid_; Elements de chimie médicale. Paris, 1851. + + _Ibid_; Traité de toxicologie. Paris, 1852. + + *Otto*; Anleitung zur Ausmittelung der Gifte, und zur Erkennung der + Blutflecken bei gerichtlich-chemischen Untersuchungen. + Braunschweig, 1870. + + *Payen*; Substances alimentaires. Paris, 1856. + + *Pelliken*; Beiträge zur gerichtlichen Medizin, Toxikologie und + Pharmakodynamik. Würztburg, 1858. + + *Petit Lafitte*; Instruction simplifiée pour la constatation des + propriétées des altérations et des falsifications des principales, + denrées alimentaires. Bordeaux, 1858. + + *Plaff*; Anleitung zur vornahme gericthlicher Blutuntersuchungen. + Plauen, 1860. + + *Pierce*; Examination of drugs, chemicals, etc. Cambridge, 1852. + + *Planta*; Verhaltung der wichtigsten Alkaloiden gegen Reagenten. + Heidelberg, 1846. + + *Pleck*; Toxicologia. Viennae, 1801. + + *Prescott*; Chemical examination of alcoholic liquors. N. Y., 1875. + + *Preyer*; Die Blutkrystalle. Jena, 1871. + + *Reese*; A manuel of Toxicology. Phila., 1874. + + *Reveil*; Introduction à un cours de toxicologie. Paris, 1859. + + *Reyer*; Die Blausäure physiologisch untersucht. Bonn., 1868. + + *Rich*; The analyst's annual note-book for 1874. London, 1875. + + *Ritter*; Ueber die Ermittelung von Blut, Samen und Excrementenflecken + in Kriminalfällen. Würztburg, 1854. + + _Ibid_; Beiträge zur gerichtlichen Chemie. St. Petersburg, 1872. + + _Ibid_; Manuel de chimie practique, analytique, toxicologique et + zoochimique. Paris, 1874. + + *Robinet (fils)*; Manuel practique d'analyse chimique des vins. + Paris, 1872. + + *Rebuteau*; Elements de Toxicologie et de médecine légale appliquée à + l'empoisonnements. Paris. 1873. + + *Roucher*; Recherches toxicologiques. Paris, 1852. + + *Roussin*; Falsification des vins par l'alun. Paris, 1861. + + *Ryan*; Medical Jurisprudence. London, 1836. + + *Schmidt*; Ein Beitrag zur Kentniss der milch. Dorpat 1874. + + *Schmidt*; Diagnostik verdächtlicher Flecken. Leipzig, 1848. + + *Schneider*; Die gerichtliche Chemie. Wien, 1852. + + *Schroff*; Toxikologische Versuche über Arsen. Wien, 1858. + + _Ibid_; Beiträge zur Kentniss des Aconite. + + *Simon*; Die Frauenmilch. Berlin, 1838. + + *Sonnenkalb*; L'Aniline et ses couleurs, au point de vue + toxicologique. Leipzig, 1864. + + *Sonnenschein*; Ueber ein neues Reagent auf Alkaloiden. Berlin, 1857. + + _Ibid_; Handbuch der gerichtliche Chemie. Berlin, 1869. + + *Soubeiran*; Nouveau Dictionnaire des falsifications et des + alterations des aliments, etc. Paris, 1874. + + *Speyer*; Recherche de la colchicine. Dorpat, 1870. + + *Spratt*; Toxicology. London, 1843. + + *Stowe*; A toxicological chart. London, 1872. + + *Tanner*; Memoranda on Poisons. London, 1872. + + *Tardieu*; Etude medico-légale sur l'empoisonnement. Paris, 1866. + + *Tardieu, Lorain et Roussin*; Empoisonnement par la strychnine, + l'arsenic, et les sels de cuivre. Paris, 1865. + + *Tatra*; Traité d'empoisonnement par l'acide nitrique. Paris, 1802. + + *Taylor*; Poisoning by strychnine. London, 1856. + + _Ibid_; On poisons, in relation to medical jurisprudence and medicine. + London, 1859. + + _Ibid_; A manual of medical jurisprudence. Phila., 1873. + + _Ibid_; The principles and practice of medical jurisprudence. + Phila., 1873. + + *Thompson*; Medical jurisprudence. London, 1831. + + *Traill*; Medical jurisprudence. Phila., 1841. + + *Trommer*; Die Kuhmilch in Berzug auf ihre Verdünnung und + Verfälschung. Berlin, 1859. + + *Valser*; Etude sur la recherche, les caractères distinctifs, et la + dosage des alcaloïdes organiques naturels. Paris, 1862. + + *Vernois*; Du lait chez la femme dans l'etât de santé et dans l'etât + de maladie. Paris, 1858. + + *Vogel*; Eine neue Milchprobe. Stuttgart, 1860. + + *Walchner*; Die Nahrungsmittel des menchens, ihre Verfälschungen und + Verunreinigungen. Berlin, 1875. + + *Walther*; Ueber Erkennung des Arsens bei Arsenvergiftung. + Bayreuth, 1854. + + *Wanklyn*; Milk Analysis. London, 1874. + + *Wenke*; Das Bier und seine Verfälschung. Weimar, 1861. + + *Werber*; Lehrbuch der praktischen Toxikologie. Erlangen, 1870. + + *Wharton and Stille*; Medical Jurisprudence. Phila., 1855. + + *Wickler*; Toxikologische Briefe. Weimar, 1852. + + *Wirthgen*; Die verschiedenen Methoden zur ermittelung von Blutflecken + in forensischen Fallen. Erlangen, 1861. + + *Witting*; Uebersicht der wichtigsten Erfahrungen in der Toxikologie. + Hannover, 1827. + + *Wöhler und Liebold*; Das forensisch-gerichtlichen Verfahren bei einer + Arsenvergiftung. Berlin, 1847. + + *Wood*; Therapeutics, materia medica and Toxicology. Phila., 1874. + + *Wormely*; The micro-chemistry of Poisons. N. Y., 1867. + + *Wurtz*; Chimie médicale. Paris, 1868. + + *Zalewsky*; Untersuchung über das Conin. Dorpat, 1869. + + +MEMOIRS. + + +On poisons generally and those not elsewhere classified. + + *Accum*; Ed. month. Rev. iii, 276; Quar. Rev. xxiv, 341; Ed. Rev. + xviii, 370. + + *Andrews*; Sill Am. Jour. [2] xlvii, 25. + + *Bouis*; Compt. rend. lxxiii. + + *Bunsen*; Ann. Ch. Pharm. cvi, 1. + + *Brunner*; Archiv. der Pharm. ccii, 4. + + *Cossa*; Gaz. Med. di Lomb., 1863. + + *Diakanow*; Med. Chem. Unters. ii, 144. + + *Duflos u. Millon*; Ann. Chem. Pharm. xlix, 308. + + *Elliot and Storer*; Am. Jour. Pharm., Sept., 1860 + + *Joubert*; Compt. Rend., No. 26. + + *Moitessier*; Annal d'Hygiene, 1868. + + *Orfila*; Mem. de l'acad. roy. de méd. viii. 493. + + *Otto*; Ann. chem. Pharm. c., 39. + + *Pellissie*; Jour. de Pharm. et de chim., Jan., 1874. + + *Reveil*; Compt. Rend. lx, 433. + + *Reynolds*; The Irish Hosp. Gaz. Feb. 15, 1873. + + *Selmi*; Gaz. Chim. Ital. 1874. fasc. I, ii. + + *Stein*; Polyt. Centralb., 1866, p. 1023 and 1870, pp. 1035, 1209. + + *Vierchow*; Arch. f. path. anat. xxi, 444. + + +On the destruction of organic matter. + + *Brande*; Arch. f. Pharm. xlviii, 206. + + *Buchner*; N. rept. f. Pharm. xvii, 21. + + *Fresenius*; Zeitsch. f. anal. Chem. 1 Jahrg, 447. + + *Fype*; Jour. f. prakt. Chem. lv, 103. + + *Graham*; Phil. Mag. [4] xxiii. + + *Liebig*; Chem. Centbl., 1857, v. 357. + + *Ludwig*; Arch. f. Pharm. xcvii, p. 23. + + *Schacht*; Arch. f. Pharm. lxxvi, 139. + + *Schneider*; Jahrb. der Chem. 1851, 630. + + *Sonnenschein*; Deutsche Klinik, 1867, No. 3. + + *Wurtz*; Am. Jour. Sci. [2] xi, 405. + + +On the detection of Arsenic. + + *Avery*; Sill Am. J. [2] xlvii, 25. + + *Barker*; Am. Chem. June, 1872. + + *Becker*; Arch. f. Pharm. xlvi, 287. + + *Bettendorff*; Zeitsch. f. Chem. v. 492, 592. + + *Blondlot*; Jahresb. 1863, 681; Compt. Rend. July 7, 1845. + + *Bloxam*; Jahresb. f. Chem. 1860. 645; Chem. Soc. Q. Jour. xiii, 14, + 138. + + *Brescius*; Ding. poly. Jour., clxxxvi, 226. + + *Buchner*; Rept. f. Pharm. xii. + + *Christison*; Lond. and Edinb., Jour. Med. Sc., Sept., 1843; Med. + Recorder, Apr., 1827. + + *Davy*; Jahresb., 1858, 609. + + *Draper*; Dingl. poly. Jour. cciv. 385. + + *Elliot and Storer*; Sill. Jour. 32, p. 380. + + *Erlenmeyer*; Zeitsch. f. Ch. u. Pharm. 1862, 38. + + *Feuchtwanger*; Sill. Jour. xix, 339. + + *Franck*; Zeit. f. anal. Chem. iv. 201. + + *Fresenius*; Arch. f. Pharm. lxii, 57; Ann. der Chem. u. Pharm. xliii. + 361; ibid, xlix, 275; Zeits. f. anal. Chem. vi, 196; ibid ii, 19; + ibid i. 483; Qual. Chem. Anal. p. 346. + + *Fresenius u. v. Baho*; Pogg, Anal. vol. xc, 565; Ann. Chem. Pharm. + xlix, 287. + + *Fype*; Phil. mag. ii 487; Jour. f. prakt. Chem. lx. 103. + + *Gatehouse*; Chem. News. No. 699, 1873. + + *Gaultier de Claubry*; J. Pharm. [3] xxii, 125. + + *Graham*; Ann. Chem. Pharm. cxxi, 63: Elements of Chem. 2nd. edit. + vol. ii, 215. + + *Gray*; Chem. News, v. 23 p. 73. + + *Hager*; Pharm. Zeitsch. 1870, No. 27: Ding. poly. Jour. vol. 207, No. + 6; Centralhalle xiii, 195. + + *Hasson*; Compt. Rend, lxvii, 56. + + *Houzeau*; Ding. poly. Jour. Bd. 207, Heft. 2, 3. + + *Hume*; Phil. Mag. Sept. 1812, 109. + + *Keber*; Viertlj. f. gerichtl. Med. ix. 96. + + *Kirschgassner*; J. f. prakt. Chem. lxviii. 168; Jahresb., 1860, 170. + + *Lippirt*; J. f. prakt. Chem. lxviii, 168; Jahresb., 1860, 170. + + *Lois*; Oest. Zeitsch. f. prakt. Heilkunde, xlix, 1859. + + *Mayer*; Pharm. Zeitsch. Russ. 2 Jahrgang. + + *Meyer*; Ann. Chem. u. Pharm., lxvi. + + *Montmeja*; La France Méd., Jan. 8, 1873. + + *Odling*; Guys. Hosp. Rep. [3] v. 367; Zeitsch. f. anal. Chem. ii. + 388. + + *Pearson*; Sill, Am. J. [2] xlviii, 190. + + *Puller*; Zeitsch. f. anal. Chem. x, 52. + + *Rose*; Pogg. Annal., vol. xc; Zeitsch. f. anal. Chem. i, 418; Chimie + Anal. Paris, 1859, p. 405. + + *Roussin*; Jahresb. 1866, 801. + + *Saikowski*; Arch. f. path. Anat. xxxi, 400. + + *Selmi*; Dent. Chem. Gess. Ber. 1872, 477. + + *Schafer*; Jour. f. prakt. Chem. lxxxii, 286. + + *Schneider*; Wien. Akad. Ber. 1851, vi, 409 + + *Sklarek*; Arch. f. Anat. u. Phys. 1866, 481. + + *Slater*; Chem. Gaz. 1851, 57. + + *Sonnenschein*; Arch. f. Pharm, cxciii, 245: ibid. [2] cxliii, 250. + + *Taylor*; Guys. Hosp. Rep. ii, 83; ibid. vi; Pharm. Zeitsch. f. Russl. + 10, Jahrg. 129. + + *Ugers*; Ann. Chem. Pharm. clix, 127. + + *Ures*; Dict. Arts, etc., new edit, i, 189. + + *Vitry*; Annal d'hygiène publ. xxxvi, 14. + + *Wackenroder*; Arch. f. Pharm. lxx, 14. + + *Watt's* Chem. Dict. i, 365; Supp. 215. + + *Werther*; J. pr. Chem. lxxxii, 235; Jahresb. 1861, 851. + + *Wiggers*; Canstatt's Jahresb. der Pharm. 1864. + + *Wittstein*; Zeitsch. f. anal. Chem. ii, 19. + + *Wohler*; Ann. der Chem. u. Pharm. lxix, 364; Mineral Analyse, + Göttingen, 1861, 213. + + *Wood and Doremus*; N. Y. Med. Press, 1859, 543. + + *Zenger*; Zeitsch. f. Ch. Pharm. 1862, 38; Jahresb. 1862, 595. + + +On the detection of Antimony. + + *Bellini*; Jhb. f. Pharm. 1868, p. 453. + + *Bottger*; Chem. Centralbl., 3 Jahrgang. + + *Bunsen*; Ann. Chem. Pharm. cvi, p. 3. + + *Hofman*; Ann. Chem. Pharm. p, 155; Chem. Soc. Quar. J. xiii, 79. + + *Millon and Levaran*; Compt. Rend. 21. + + *Odling*; Guys Hosp. Rep. [3] ii, 249. + + *Pfaff*; Pogg. Ann. f. Phys xl, 339. + + *Thompson*; Jour. f. prakt. Chem. ii, 369. + + *Vogel*; ibid, xiii, 57. + + +On the detection of Mercury. + + *Buchner*; N. rept. f. Pharm. xvii, 272. + + *Erdman and Marchand*; Jour. f. prakt. Chem. xxxi. + + *Hittdorf*; Pogg. Annal. cvi. + + *Konig*; Jour. f. prakt. Chem. lxx. + + *Mayencon and Bergeret*; Jour. de l'Anat. et de la Physiol. 1873, No. + 1; Jour. de Pharm. et de Chim., Aug., 1873. + + *Schneider*; Ber. d. Wien, Akad. d. Wiss. xl. + + *Wormley*; Chem. News, ii, No. 43. + + +On the detection of Phosphorus. + + *Barrett*; Phil. Mag. [4] xxx, 321. + + *Blondlot*; Jour. de. Phy. et de Chim. 3 é serie xl, p. 25. + + *Bostelaer*; Jour. de Pharm. et de Chim., May, 1873. + + *Christoffle and Beilstein*; Ann. de Chim. v, iii, p. 80. + + *Dalmon*; Zeitsch. f. anal. Chem. 1871, 132. + + *Dusard*; Zeitsch. f. anal. Chem. i, 129; Compt. rend. xliii, 1126. + + *Ferrand*; La France med., Jan. 18, 1873. + + *Fresenius and Neubauer*; Zeitsch. f. Anal. Chem. i, 366. + + *Hager*; Zeitsch f. anal. Chem. 1870, 465. + + *Hoffman*; Jahresb. 1859, 663. + + *Klewer*; Pharm. Zeitsch. f. Russl., 386. + + *Kohler*; Poly. centralh., 1871, 263. + + *Lapeyrere*; La France méd., Jan. 4, 1873. + + *Lefort*; Jour. de Pharm. et de Chim., Aug., 1874. + + *Lispowitz*; Ann. f. Phys. u. Pharm. cviii, 625. + + *Mistcherlich*; Jour. f. prakt. Chem. lxvi, 238. + + *Mulder*; Arch. f. d. holl. Zeit. ii, 4; Zeitsch. f. Anal. Chem. ii, + 3. + + *Otto*; Zeitsch. f. Chem. [2] ii, 733. + + *Pribram*; Zeitsch. f. anal. Chem. 1871, 109. + + *Ritter*; Thése de doctorat es sciences, Paris, 1872. + + *Scherer*; Ann. Ch. Pharm. cxii, 214. + + *Schieffendecker*; Zeitsch. f. anal. Chem. 1872, iii. + + *Schom*; Zeitsch. f. anal. Chem. [2] v, 664. + + *Wiggers*; Canstatt's Jahresb. f. Pharm. 1854. + + +On the detection of Prussic Acid. + + *Almen*; Chem. Centralb., 1871, 797. + + *Bonjean*; Compt. rend. lxx, 532. + + *Braun*; Zeitsch. f. anal. Chem. iii, 464. + + *Duvignan and Parent*; Am. Med. Rec. 1819, 534. + + *Hagenbach*; Arch. f. path. Anat. xl, 125. + + *Hoppe-Seyler*; Vierschow's Arch. f. path. Anat 38. + + *Jacquemin*; Compt. rend. lxxxix, 1499, 1502. + + *Letheby*; Lond. Lanc. 1844, 244; ibid, vol. 2, p. 139. + + *Ralph*; N. Jahresb. f. Pharm. xxx, 179. + + *Rennard*; Pharm. Zeitsch. f. Russl. xii, No. 8. + + *Schonbein*; Zeitsch. f. anal. Chem. 1868, 503. + + *Siegel*; Arch. f. Heilkunde, 1858. + + *Struve*; Zeitsch. f. anal. Chem. 1873, i; Mon. Scien. Ques. Juin, + 1874, 538. + + *Taylor*; Ann. Ch. Pharm. lxv, 263. + + +On the detection of Alkaloids in general. + + *Anderson*; Pharm. Centralbl., 1848, 591. + + *Armstrong*; J. Chem. Soc., v. 8, p. 56. + + *Back*; Jour. f. prakt. Chem. Nos. 5-6, 1873. + + *Beas*; Jour. de Phys. et de Chim., Sept. 1872. + + *Bolton*; (trans. of the Stas-Otto method) Am. Chem., Nov., 1873. + + *Bonnemains*; Compt. Rend. xxxvi, 150. + + *Bouchardt*; Ann. de Phys. et de Chim., 3e série. t. ix. + + *Brunner*; Archiv der Pharm., April, 1873. + + *Buignet*; Jour. de Pharm. et de Chim. t. xx, 252. + + *Deane and Brady*; Chem. Soc. J. [2] iii, 34. + + *Deefs*; N. Jahresb. f. Pharm. ii, 31; Wittstein's Viertelj. vi. + + *Dragendorff*; Pharm. Zeitsch. f. Russl. ii, 459; Archiv der Pharm. + May, 1874. + + *Erhard*; N. Jahresb. f. Pharm. xxv, 129, 193, 283; ibid, xxvi, 9, + 129. + + *Ewers*; Pharm. Zeitsch. f. Russl. xii, No. 23. + + *Graham and Hofman*; Chem. Soc. Qu. J. v, 173; Pharm. J. Trans. xi, + 504; Ann. Ch. Pharm. lxxxiii, 39. + + *Grandean*; Bull. Soc. Chim. [2] ii, 74. + + *Guy*; Pharm. Jour. ii, pp. 553, 602; ibid, iii, pp. 11, 112. + + *Hagers*; Chem. Ctbl., 1869, 131. + + *Horsley*; Chem. News, v, 355 + + *Huseman*; Ann. Chem. Pharm. cxxviii, 305. + + *Kletzinsky*; Mitthel. v. d. Geb. d. rein. u. angew. Chem. 1865. + + *Kohler*; Archiv der Pharm. Mar. 1873. + + *Kuhne*; Ann. Chem. Pharm. vol. civ. + + *Lefort*; Zeitsch. f. anal. Chem. i, 134. + + *Lehrman*; Archiv der Pharm. 2 Bd. lxxvi, 144. + + *Liebig*, Poggendorff u. Wohler; Handwörterb. d. Chem. 2 Aus. i, 464. + + *Macadams*; Pharm. Jour. Trans. xvi, 120, 160. + + *Marchattie*; Chem. News. x, 183. + + *Marme*; Bull. Soc. Chim [2] ix, 203; Zeitsch. f. rat. Med. 1867. + + *Mayer*; Jour. de Pharm. et de Chim., Oct. 1873; Oest Zeitsch. f. + Pharm. ii, 232. + + *Nowak*; Dingls. poly. Jour., vol. 206, p. 422; Sitzber. d. Wiener + Akad. d. Wissensch., 1872. + + *Otto*; Ann. Ch. Pharm. c, 39. + + *Orfila*; Jour. de. Chim. et Méd. [4] t. vii, 397. + + *Palm*; Pharm. Zeitsch. f. Russl. i, Jahxgang. + + *Pierce*; J. Chem. Soc., Nov. 1874. + + *Prollius*; Chem. Centralbl., 1857, 231. + + *Ritter*; Pharm. Zeitsch. f. Russl. 5-6 Jahrg. + + *Rodgers and Girdwood*; Jahresb. v. Liebig u. Kopp, 1857, 603; Pharm. + Jour. Trans. xvi, 497. + + *Rorsch and Fasbender*; Deut. Chem. Gess. Ber. xii, 1064. + + *Scheibler*; Jahresb. 1863, 702; Arch. f. Pharm. lix; Jour. f. prakt. + Chem. lxxx, 211. + + *Schneider*; Ann. Chem. Pharm., von Poggendorff, No. 9. + + *Schrage*; Archiv der Pharm., Dec., 1874. + + *Schroof*; Apothet. Jahrg., ix, 148. + + *Schulze*; Ann. Ch. Pharm. cxix, 177. + + *Schwanert*; Deut. Chem. Gess. Ber., No. 14, 1874. + + *Sonnenschein*; ibid, civ, 45. + + *Stas*; Bull. de l'Acad. Roy. de Méd. de Belgique, xi, 304 (1851); + Ann. Ch. Pharm., lxxxiv, 379, J. Pharm. Chim., xxii, 281; + Jahresb., 1851, 640; Jour. f. prakt. Chem., lix, 232. + + *Struve*; Zeitsch. f. anal. Chem., No. 2, 1873. + + *Thomas*; ibid, vol. i, 317. + + *v. Uslar and Erdman*; Ann. der Chem. u. Pharm., 120, p. 121; 122, p. + 360. + + *de Vrij and van der Burg*; Jahresb. v. Liebig u. Kopp, 1857, 602. + + *Watts*; Chem. Dict., vol. i, p. 125. + + *Wagner*; Fresen. Zeitsch. f. anal. Chem., iv. + + +On Atropine. + + *Brunner*; Archiv der Pharm., April, 1873. + + *Calmberg*; ibid. Nov., 1874. + + *Gulielmo*; Zeitsch. f. anal. Chem., ii, 404. + + *Helwig*; Wiener Akad. Ber. vii, 433. + + *Koppe*; Pharm. Zeitsch. f. Russl., 5 Jahrgang. + + *Pelikan*; ibid, 1 Jahrgang. + + *Wormley*; Chem. News, vol. ii, June, 1860. + + +On Brucine. + + *Cotton*; Zeitsch. f. Chem. [2] v. 728. + + *Helwig*; Zeitsch. f. anal. Chem., iii, 43. + + *Luck*; Zeitsch. f. Chem. [2] vi, 275. + + *Mayer*; Rep. Chim. app., v, 102. + + *Strecker*; Ann. Ch. Pharem., xci, 76. + + *Trapp*; Jahresb. 1863, 702. + + *Wormley*; Chem. News, vol. ii, July, 1860. + + +On Morphine. + + *Anderson*; Ann. Ch. Pharm., lxxv, 80. + + *Dupre*; Chem. News, viii, 267; Jahresb., 1863, 704. + + *Erdman*; Ann. Ch. Pharm. cxx, 88; ibid, cxxii, 360. + + *Flandin*; Compt. rend., xxxvi, 517. + + *Frohde*; Zeitsch. f. anal. Chem. v, 214; Arch. f. Pharm., clxxvi. + + *Huseman*; Ann. Ch. Pharm., cxxviii, 305. + + *Kalkbrunner*; Zeitsch. d. all. Oest. Apot. Ver., No. 27. + + *Lassaigne*; Ann. Ch. Pharm. [2] xxv, 102. + + *Lefert*; J. Pharm. [3] xl, 97. + + *Mermer*; J. Chim., xxiii, 12. + + *Wormley*; Chem. News, vol. ii, Sept., 1860. + + +On Strychnine. + + *Bingley*; Chem. Gaz., 1856, 229. + + *Brieger*; Jahresb. pr. Pharm. xx, 87. + + *Cloetta*; Zeirsch. f. anal. Chem., v, 265. + + *Davy*; J. Pharm. [3] xxiv., 204. + + *Djurberg*; Chem Centralb., 1872, 153; Zeitsch. f. anal. Chem., 1872, + 440. + + *Eboli*; Archiv der Pharm., cxxxv, 186. + + *Erdman and Marchand*; Jour. f. prakt. Chem., xxxi, 374. + + *Gorup-Besenez*; Handwörterb. [2] i, 468. + + *Graham and Hofman*; Pharm. Trans., xi, 504; Chem. Gaz., 1852, 197; + Ann. Ch. Pharm., lxxxiii, 39. + + *Hagen*; Ann. Ch. Pharm. ciii, 159. + + *Hunefeld*; Schw., lx. 454. + + *Janssen*; Zeitsch. f. anal. Chem., 4 Jahrgang. + + *Jordan*; N. Repert., x, 156. + + *Letheby*; Pharm. J. Trans. xvi, 10. + + *Mack*; N. Br. Arch., xlvi, 314. + + *Marchand*; Chem. Gaz., June 15, 1844. + + *Mayer*; J. Pharm. [3] xlvi. + + *Reese*; Chem. News. 1862, 316. + + *Rousseau*; J. Chim. Méd. xx, 415. + + *Sonnenschein*; Jahresb. 1870, 1032; Ber. d. Deutsch. Chem. Gess. iii, + 653. + + *Schroder*; N. Br. Arch., xciii, 190. + + *Thomas*; Amer. Jour. Pharm. 1862, 227. + + *Thompson*; Pharm. J. Trans., ix., 24. + + *Vogel*; N. Repert. Pharm., ii, 560. + + *de Vrij and van der Burg*; Pharm. J. Trans. xvi, 448. + + *Wagner*; Kopp's Jahresb., 1861, 857; Zeitsch. f. anal. Chem., vi, + 387. + + *Wittstein*; Pharm. Viertelj., vi, 273. + + *Wormley*; Am. Jour. Sc. and Arts., xxviii, Sept., 1859. + + +On the detection of Falsifications of Writings. + + *Lucas*; Chem. Centralb., 1868, 1517. + + *Knecht-Senefelder*; Technol., xxvi, 143. + + *Moride*; Compt. rend., lviii, 367; Ding. poly. Jour. clxxii, 390. + + *Vorwerk*; Ding. poly. Jour., clxxii, 158. + + *----*; Berl. ind. Z., 1864, 41. + + +On the detection of adulterations in Flour and Bread. + + *Barral*; Compt. rend., lvi, 834. + + *Bastelaer*; Chem. Centralb., 1868, 1342. + + *Cailletet*; ibid, 1858, 1392. + + *Corput*; ibid, 1860, 207. + + *Crooks*; Chem. News., vol. xxxiii, 73. + + *Danckwort*; Archiv der Pharm. [2] xx, 47. + + *Davis*; Chem. News, xxv., 207. + + *Eulenberg and Vohl*; Poly. Centralb., cxcvii, 530. + + *Gobley*; Jour. de Pharm., April, 1844. + + *Hadon*; Chem. News, 1862. + + *Hager*; Ding. Poly. Jour., clxxiii, 159. + + *Harsley*; Archiv der Pharm., July and Dec., 1873; Chem. News, xxv, + 230. + + *Moitessier*; Annal. d'Hygiene, 1868. + + *Odling*; J. Soc. Arts, April 9, 1858. + + *Oser*; Ding. poly. Jour., clxxxiii, 256. + + *Rivot*; Ann. de Phys. et de Chim., 3e série t, xlvii. + + *Rummel*; Ding. poly. Jour., cxxxix, 49. + + *Tasbender*; Ding. poly. Jour., No. 6, ccvi. + + *Wanklyn*; Archiv der Pharm., Dec., 1873; Chem. News, xxxiii, No. + 736; Ber. Med. Jour., March 29, 1873. + + +On the examination of Fatty Oils. + + *Behrens*; Ding. poly. Jour., cxxxi, 50. + + *Calvert*; Pharm. J. Trans., xiii, 356. + + *Clarke*; Chem. News, xxiii, 145. + + *Dingl*; Poly. Jour., clxxiv. + + *Donny*; Bull. Soc. d'Erc, 1864, 372; Jahresb., 1864, 734. + + *Dragendorff*; Pharm. Zeitsch. f. Russl., ii, 434. + + *Fluckiger*; Chem. Centralb., 1871, 55. + + *Glassner*; (trans.) Am. Chem., Dec., 1873. + + *Gobley*; J. Pharm. [3], iv, 285; ibid. v. 67. + + *Jacobson*; Bull. Soc. Chim., [2] vii, 96. + + *Langlies*; Zeitsch. f. anal. Chem., 1870, 534. + + *Ludwig*; Archiv der Pharm., [3] i, 1. + + *MacNaught*; Chem. Centralb., 1862, 742. + + *Massie*; Zeitsch. f. anal. Chem., 1871, 495. + + *Maumene*; Compt. rend., xxxv, 572. + + *Nickles*; Bull. Soc. Chim., [2] vi, 89 + + *Penot*; Bull. de Mullh., xxvi, 7; Jahresb., 1866, 827. + + *Roth*; Bull. de Mullh., 1864, 104. + + *Ure's* Dict. of Arts, etc., iii, 300. + + *Vogel*; Chem. Centralbl., 1863, 945. + + *Watt's* Dict. of Chem., iv., 182. + + +On the examination of Milk. + + *Boussingault*; Ann. Chem. Phys. [4] xxv, 382. + + *Baumhauer*; J. pr. Chem., lxxxiv, 145. + + *Casselman*; Chem. Centralb., 1863, 689. + + *Dancer*; Chem. News, v, 21, p. 51. + + *Daubrawa*; Jour. f. prakt. Chem., lxxviii, 426. + + *Donne*; Compt. rend., xvii, pp. 585, 591. + + *Filhol and Joly*; Wurtz's Dict. de Chim., t. ii, p. 195. + + *Gmelin*; Handb. der Chem., viii, [2] 246-273. + + *Heeren*; Chem. Centralb., 1870, 304. + + *Hermstaedt*; Pharm. Centralb., 1833, 401. + + *Kletzinsky*; Chem. Centralb., 1861, 244. + + *Lade*; Chem. Centralb., 1858, 144. + + *Leconte*; ibid, 1854, 1465. + + *Lehman*; Lehrb. der Phys. Chem., 1863, ii, pp. 287, 301; (trans. by + Day) ii, pp. 449, 475. + + *Macadams*; Am. Chem., May, 1875, 419. + + *Marchand*; Jour. de Pharm., Nov., 1854. + + *Michaelson*; Ding. poly. Jour., cxlix, 59. + + *Millon*; Compt. rend., lix, 396. + + *Muller*; Zeitsch. f. anal. Chem., No. 3, 1872. + + *Otto*; Ann. Chem. Pharm., cii, 47. + + *Pelouze and Fremy*; Traité de Chim. gen., [2 edit.] Paris, 1857, p. + 195. + + *Pribram*; Dings. poly. Jour., cxcvii, 448 + + *Reichelt*; Bayr. K. u. Gwbl., 1859, 602. + + *Reineck*; Ding. poly. Jour., cci, 433. + + *Rosenthal*; Chem. Centralb., 1854, 1392. + + *Seely*; Sill. Am. J., vii, 293. + + *Vernois and Becqueret*; Ann. d'Hygiéne, April, 1853. + + *Voelcker*; Am. Chem., May, 1875, p. 412. + + *Vogel*; Poly. Notizbl., No. 10, 1874. + + *Wanklyn*; Pharm. Viertelj., xx, 201: Milk Jour., 1, 109, 160; Chem. + News, xxviii, No. 623; ibid, No. 736; Pharm. Journ. Trans., [3] i, + 605. + + +On the detection of adulteration in Wine and Beer. + + +WINE. + + *Beck*; Edinb. Phil. Jour., 1835. + + *Berthelot and Fleurien*; Compt. rend., lvii, 394. + + *Blume*; Dings. poly. Jour., clxx, 240. + + *Bolly and Paul*; Manual of Tech. Anal., p. 331. + + *Boyer and Coulet*; Compt. rend., lxxvi, 585. + + *Brande*; Phil. Trans., 1811. + + *Cotlini*; Ann. du Genie Civil, No. 3, 1873. + + *Cotlini and Fantazini*; Ann. di Chim. Appl. alla Medi., Juli, 1870. + + *Christison*; Edinb. Phil. Jour., 1838. + + *Diez*; Ann. Ch. Pharm., xcvi, 304. + + *Duclaux*; Ann. de Chim. et de Phys., July and Sept., 1874; Compt. + rend. lxxviii, 1159. + + *Duffield*; Am. Jour. Pharm., Mar. 1862. + + *Dupre*; Chem. Soc. Jour. xx, 493. + + *Fantenelle*; J. Chim. Méd., iii, 332. + + *Faure*; J. Pharm., vii, 200. + + *Fischern*; Ann. Chem. Pharm., lviii, 705. + + *Fresenius*; ibid, lxiii, 384. + + *Geiger*; Mag. f. Pharm., xix, 266. + + *Geromont*; Ann. Ch. Pharm., xvii, 158. + + *Hager*; Zeitsch. f. anal. Chem., 1872, 337. + + *Hitchcock*; Edinb. Phil. Jour., xxxvii, 176. + + *Jacquemin*; Ann. de Chim. et de Phys. v, série, Nov., 1874; Compt. + rend., lxxix, 523. + + *Kersting*; Ann. Ch. Pharm., lxx, 50. + + *Khol*; J. Chim. Méd., [4] ii, 251. + + *Liebig, Poggendorff and Wohler*; Handwörterb. ix, 676. + + *Ludersdorf*; J. f. prak. Chem., xxiv, 102. + + *Maisch*; Proc. Am. Pharm. Assn., 1863, 296; 1864, 291; 1866, 267. + + *Mallard*; J. Chim. Méd., iii, 326. + + *Maumene*; Bull. Soc. Chim., xxii, No. 1. + + *Miller*; Jour. de Pharm. et de Chim., Mar., 1873. + + *Mitis*; Baierisch. K. u. Gewerbeblatt, 1838. + + *Phipson*; Zeitsch. f. anal. Chem., ix, 121. + + *Reiman's* Farb. Zeit., Nos. 14-15, 1874. + + *Romei*; Mon. Scien., iii, t. iii, No. 382. + + *Salleron*; Compt. rend., lxxviii, No. 16. + + *Scheitz*; Arch. Pharm., [3] v, 331. + + *Schubert*; Pogg. Annal., lxx, 397. + + *Sestini*; Landwirthsch. Ver. Stat., xv, 9. + + *Tuchschmeidt*; Jahresb., 1871, 967. + + *Zierl*; Baierisch. Kunst. Gewerbebl, 1838. + + +BEER. + + *Blas*; Viertelj. f. prakt. Pharm., xxi, 584. + + *Brunner*; Archiv der Pharm., April, 1873; Dings. poly. Jour., ccix, + No. 6; Jour. de Pharm. et de Chim., Sept., 1873; Poly. Nolizblatt, + No. 17, 1873. + + *Dietz*; Neues Jahresb. f. Pharm., xxxix, No. 1. + + *Dragendorff*; Archiv. der Pharm., April and May, 1874; Dings. poly. + Jour., ccxiv, pp. 33, 389. + + *Dullo*; Wieck's Gaz., 1865, 64. + + *Gunckel*; Arch. f. Pharm., clxiv. + + *Kubinki*; Le Technol, No. 397; (trans.) Amer. Chem., Nov., 1874; + Dings. poly. Jour. ccxi, 360. + + *Langley*; Chem. Centralb., 1865, 184. + + *Meme*; Compt. rend., 2me sem., No. 123. + + *Michælis*; Ill. Gewerbz., 1871, 8. + + *Muspratt's* Chem. i, 281. + + *Pohl*; Wiener Akad. Ber., xii, 88. + + *Ritter*; Pharm. Zeitsch. f. Russl., i, pp. 304, 414. + + *Shafhauel*; Ding. poly. Jour., cxxxii, 299. + + *Schmidt*; Jour. f. prakt. Chem., lxxxvii, 344. + + *Stolber*; ibid, xciv, iii. + + *Ure's* Dict. Chem., 4th edit., 1831, p. 203. + + *Vogel and Hammon's* Mitth., 1860, 184. + + *Wittstein*; Archiv der Pharm., Jan. 1875. + + +On the testing of Vinegar. + + *Bussy and Buignet*; Jahresb., 1865, 69. + + *Greville*; Ding. poly. Jour., cxxxi, 139. + + *Liebig, Poggendorff and Wohler*; Handwörterb, ii, 867. + + *Mohr*; Ann. Ch. Pharm., xxxi, 277. + + *Mollerat*; Ann. Chim., lxviii, 88. + + *Nicholson*; Ding. pol. Jour., cxxxix, 441. + + *Otto*; Ann. Chem. Pharm., cii, 69. + + *Roscoe*; Chem. Soc. Jour., xv, 270. + + *Runge*; Gewz. Bayer. 1871, 4. + + *Strohl*; Jour. de Pharm. et de Chim., Sept., 1874. + + *Toorn*; Jour. f. Chem., vi, 171. + + *Wagner*; Chem. Tech., (English trans.) p. 467. + + *Williams*; Pharm. J. Trans., xiii, 594. + + +On the detection of adulterations in Sulphate of Quinine. + + *Delondre and Henry*; J. Pharm., [3] xxi, 281. + + *Gmelin's* Handbuch, xvii, 280. + + *Guibourt*; J. Pharm., [3] xxi, 47. + + *Henry*; ibid, xiii, 107. + + *Hesse*; Ann. Ch. Pharm., cxxxv, 325; Jahresb., 1865, 441. + + *Korner*; Zeitsch. f. Chem., J. i, 150; Jahresb. 1862, 619. + + *Phillips*; Lond. Lanc., i, 820. + + *Riegel*; Jahresb. f. Pharm., xxv, 340. + + +On the detection of Blood Stains. + + *Barruel*; Ann. d'Hygiéne pub., i. 267; ibid, No. 6, 1829. + + *Bertolet*; Am. Jour. Med., Sc., Jan., 1874. + + *Brucke*; Jahresb., 1857, 609. + + *Van Deen*; Zeitsch. f. anal. Chem., ii, 459. + + *Erdman*; Jour. pr. Chem., lxxxv, 1; Jahresb., 1862, 634. + + *Falck*; Ber. Klinisch. Wochb., 1872. + + *van Geuns and Gunning*; Zeitsch. f. anal. Chem., 1871, 508. + + *Gwosden*; Wiener Akad. Ber., liii, [2] 683; Jahresb., 1866, 746. + + *Helwig*; Zeitsch. f. anal. Chem., 1872, 244. + + *Hirsch*; N. J. Pharm., xxxii, 140. + + *Hoppe-Seyler*; Med. Chem. Unters., i, 298; Jahresb., 1867, 805. + + *Krauss*; Jahresb., 1861, 792. + + *Liebig, Poggendorff and Wohler*; Handwörterb., iv, 177. + + *Liman*; Jahresb., 1863, 715. + + *Lowe*; Pharm. Centralb., 1854, 137. + + *Mandl*; Lond. Lanc., Dec. 17, 1842, 176. + + *Muller*; Zeitsch. f. anal. Chem., 1872, iii. + + *Orfila*; Jour. des Progés des Sc., iv, 1827; Archiv. gen. de Méd., + Fev., 1828. + + *Papillon*; Mon. Scien. Ques., Jan., 1874, 59. + + *Reynolds*; Br. Med. Jour., Jan. 4, 1873. + + *Rose*; Jahresb. der Pharm., ii, 365; Jahresb., 1854, 754. + + *Roussin*; Ann. d'Hyg. et de Méd. lég., 1865. + + *Scriba, Simon and Buchner*; Jahresb., 1859, 706. + + *Sonnenschein*; Jour. de Pharm. et de Chim., July, 1874; Mon. Scien., + ii, 370. + + *Sorby*; Chem. News, 1865, xi, pp. 186, 194, 232, 256. + + *Struve*; Zeitsch. f. anal. Chem., 1872, 29. + + *Taylor*; Guy's Hosp. Rep., 1868. + + *Wicke*; Pharm. Centralb., 1854, 431. + + *Wittstein*; Arch. der Pharm., ii, 128. + + *Zollikopfer*; Ann. d. Chem. u. Pharm., xciii, 237; Pharm. Centralb., + 1855, 217. + + +On the detection of Spermatic Stains. + + *Bayard*; Ann. d'Hygiéne. pub., 1849, No. 43. + + *Renak*; Diagnostisch. u. Pathologisch. Unters. Berlin, 1845, pp. 148, + 171. + + *Schmidt*; Diagnostik Verdäch. Flecken, Leipzig, 1848, pp. 42-48. + + * * * * * + +The following are the most important works relating to poisons and +food-adulteration that have been issued since the publication of the +first edition of this book: + + *Adam*; Étude sur les principales methodes d'essai et d'analyse du + lait. Paris, 1879. + + *Averbeck*; Die Verfälschung der Nahrungsmittel. Bremen, 1878. + + *Bastide*; Vins sophistiqués. Beriès, 1876. + + *Bauer*; Die Verfälschung der Nahrungsmittel. Berlin, 1877. + + *Bell*; Analysis and adulteration of food. 1881. + + *Binz*; Intoxicationen. Tübingen, 1878. + + *Birnbaum*; Einfache Methoden zur Prüfung Lebensmittel. 1877. + + *Blane*; De la contrefaçon. + + *Blas*; De la présence de l'acide salicylique dans les bierres. + Paris, 1879. + + *Blochman*; Ueber Verfälschung der Nahrungsmittel. Königsberg, 1881. + + *Blyth*; Dictionary of Hygiene. London, 1877. + + _Ibid_; Manual of chemistry. London, 1879. + + _Ibid_; Foods, composition and analysis. London, 1882. + + _Ibid_; Poisons, effects and detection of. London, 1882. + + *Boehn*; Herzgifte. + + *Bolley*; Manuel pratique d'essai et de recherches chimiques. + Paris, 1877. + + *Bronner*; Chemistry of food and drink. London. + + *Caldwell*; Agricultural chemical analysis. N. Y., 1879. + + *Casper*; Handbuch der gerichtlichen Medizin. Berlin, 1881. + + *Church*; Food. N. Y., 1877. + + *Cooley's* Practical receipts. + + *Dannehl*; Die Verfälschung des Bieres. Berlin, 1877. + + *Dietzsch*; Die wichtigsten Nahrungsmittel, etc. Zurich, 1878. + + *Dragendorff*; Recherches des substances amères dans la bière. + Paris, 1876. + + _Ibid_; Gerichtlich chemische Ermittellung von Giften. +St. Petersburg, 1876. + + *Elsner*; Die Praxis Nahrungsmittel Chemikers. Leipzig, 1880. + + *Eulenberg*; Handbuch der Gewerbe-Hygiene. Berlin, 1876. + + *Falk*; Lehrbuch der praktischen Toxicologie. Stuttgart, 1880. + + *Flick*; Die Chemie im Dienst der öffentlichen Gesundheitspflege. + Dresden, 1882. + + *Fluegge*; Lehrbuch der hygienischen Untersuchungsmethoden. + Leipzig, 1881. + + *Focke*; Massregeln gegen Verfälschung der Nahrungsmittel. + Chemnitz, 1877. + + *Fox*; Sanitary examination of water, air, and food. 1878. + + *Franchini*; Palmelle prodigieuse. Bologne, 1880. + + *Gamgee*; Text-book of physiological chemistry. London, 1880. + + *Gaultier*; La sophistication des vins. Paris, 1877. + + *Gimlini*; Experimentelle Untersuchung über die Wirkung des Aconitins. + Erlangen, 1876. + + *Goppelsroeder*; Sur l'analyse des vins. Mulhouse, 1877. + + *Grandeau*; Handbuch für agricultur-chemische Analysen. Berlin, 1880. + + *Griessmayer*; Die Verfälschung der wichtigsten Nahrungs-und + Genussmittel. 1880. + + *Hahn*; Die wichtigsten d. his jetzt bekannten Geheimmittel u. + Specialitäten. 1876. + + *Hausner*; Fabrikation der Conserven und Conditen. Leipzig, 1877. + + *Hemming*; Aids to forensic medicine and toxicology. London, 1877. + + *Hilger*; Die wichtigsten Nahrungsmittel. Erlangen, 1879. + + *Hoffman*; Lehrbuch der gerichtlichen Medizin. Wien, 1880. + + *Hoppe-Seyler*; Physiologische Chemie. Berlin, 1878. + + *Husson*; Du vin. Paris, 1877. + + _Ibid_; Le lait, la créme, et le beurre. 1878. + + *Johnson's* Encyclopædia, vol. iv. p. 752. + + *Johnson*; Chemistry of common life. N. Y., 1880. + + *Judell*; Die Vergiftung mit Blausäure. Erlangen, 1876. + + *Kensington*; Analysis of foods. London, 1879. + + *Klencke*; Illustrirtes Lexicon der Verfälschung der Nahrungsmittel + und Getränke. Leipzig, 1878. + + *Koenig*; Chemische Zusammensetzung der menschlichen Nahrungsmittel. + + *Lang*; Die Fabrikation der Kunstbutter, Sparbutter, und Butterin. + 1878. + + *Lessner*; Atlas der gerichtlichen Medizin. Berlin, 1883. + + *Lieberman*; Anleitung zur chemischen Untersuchung auf der Gebiete + der Medicinal-polizei. Stuttgart, 1877. + + *Lintner*; Lehrbuch der Bierbrauerei. 1877. + + *Loebner*; Massregeln gegen Verfälschung der Nahrungsmittel. + Chemnitz, 1877. + + *Luerssen*; Medicinisch Botanik. Leipzig, 1883. + + *Maschka*; Handbuch der gerichtlichen Medizin. Tübingen, 1882. + + *Medicus*; Gerichtlich-chemische Prüfung von Nahrungs-und + Genussmitteln. 1881. + + *Montgomery*; Essai de Toxicologie. Paris, 1878. + + *Muter*; A key to organic materia medica. 1879. + + *Ogston*; Lectures on medical jurisprudence. London, 1878. + + *Palm*; Die wichtigsten und gebrauchlichsten Nahrungsmittel. + St. Petersburg, 1882. + + *Parkes*; Hygiene. Phila., 1878. + + *Pasteur*; Études sur la bière. Paris, 1876. + + *Pavy*; A treatise on food and dietetics. London, 1875. + + *Pennetier*; Leçons sur les matières premières organiques. + Paris, 1881. + + *Praag*; Leerbock voor practische Giftleer. Utrecht. + + *Pratt*; Food adulteration. Chicago, 1880. + + *Prescott*; Proximate organic analysis. N. Y., 1882. + + *Ritter*; Des vins colorés par la fuchsine. Paris, 1876. + + *Reitleitner*; Die Analyse des Weines. Wien, 1877. + + *Schnacke*; Wörterbuch der Verfälschung. Jena, 1877. + + *Schmidt*; Anleitung sanitarisch-und polizeilich-chemischen + Untersuchungen. Zurich, 1878. + + *Schroff*; Beitrag zur Kenntniss des Aconits. Wien, 1876. + + *Selmi*; Chimica applicata all' igiene alla economia domestica. Milan. + + *Sharples*; Food and its adulteration. Preston, 1879. + + *Smith*; On foods. N. Y., 1873. + + *Smith, Ed.*; Manual for medical officers of health. London, 1874. + + _Ibid_; Handbook for inspectors of nuisances. London. + + *Spon's* Encyclopædia. London, 1882. + + *Squibb*; Proper legislation on adulteration of food. N. Y., 1879. + + *Steirlin*; Ueber Weinverfälschung und Weinfarbung. Bern, 1877. + + _Ibid_; Das Bier und seine Verfälschung. Bern, 1878. + + *Thudicum and Dupre*; Wine. + + *Vogel*; Praktische Spectral-analyse. Nordlingen, 1877. + + *Wanklyn*; Tea, coffee, and cocoa. London, 1874. + + *Wanklyn and Cooper*; Bread analysis. London, 1881. + + *Wenyl*; Analytisches Hülfsbuch. Berlin, 1882. + + *Wittstein*; Taschenbuch des Nahrungs-und Genussmittel Lehre. + Nordlingen, 1877. + + *Woodman*; Handbook of forensic medicine. London, 1877. + + *Wurtz*; Traité élémentaire de chimie médicale. Paris. + + +MEMOIRS. + + +Alkaloids. + + Journal Chem. Soc. i, 1877, p. 143; ibid, i, 1878, p. 151; ibid, May, + 1882; ibid, ccxliv, 1883, p. 358. + + Trans. Internat'l Med. Cong., 1881, vol. i, p. 472. + + Virch., Arch. bd. 79, 1880, s. 292; ibid, bd. 87, 1882, s. 410. + + Archiv. d. Pharm., Jan. 7, 1882; ibid, [3] vii, pp. 23-26; ibid, [3] + vi, p. 402. + + Liebig, Anal. bd. 708, 1881. + + Berl. Klin. Wochenschr. 1876, 27. + + Pflüger's, 23, 433. + + Lancet, Sept. 30, 1880; ibid, Nov. 28, 1882; ibid, Nov. 13, 1882. + + Bull. Farm. Milano, 1881, p. 197. + + Zeitsch. f. Anal. Chem. i, 517. + + Gazett. Chim. Ital. vi, 153-166. + + Pharm. Zeitschr. f. Russland, i, p. 277. + + Vierteljahrsschr. f. gericht. Med. xxiii, p. 78. + + +Arsenic and Antimony. + + Archiv, f. exper. Path. u. Pharm., Leipzig, 1882. + + Pharm. Journ. Trans. [3] pp. 81-83. + + Med. Jahrbuch, 1880. + + Journ. d'Hygiène, Juil., 1878. + + Medical Times and Gaz. 1876, p. 367. + + Chem. News, Jan., 1881, p. 21; ibid, xxxiii., pp. 58 and 74. + + Am. Chem. Journ. ii, No. 4. + + Bull. Soc. Chim. [2] xxvi, p. 541; ibid, Jan. 7, 1877. + + Zeitsch. f. Anal. Chem. xiv, pp. 250, 281, 356; ibid, i, p. 445. + + Liebig, Anal. ccvii, p. 182. + + Lancet, 1879, p. 699; ibid, May 19, 1883. + + Journ. Chem. Soc. No. 1, 1876. + + +Mercury, Copper and Lead. + + Zeit. f. Phys. Chem. 1882, i, p. 495. + + Analyst, 1878, p. 241. + + Chem. News, xxxi, p. 77; ibid, xxxi, p. 801; ibid, xxxiv, pp. 176, + 200, and 313. + + Analyst, 1877, pp. 13 and 216. + + Journ. Chem. Soc. 1876, ii, p. 4. + + Dingl. Pol. Journ. ccxx, 446. + + Med. Gazette, xlviii, 1047. + + +Prussic Acid. + + Analyst, Apr., 1877, p. 5. + + Bull. Gen. de Thér. No. 30. + + Am. Journ. Phys. Sci., Arnold, 1869. + + Virch., Arch. f. Path. Anat. bd. 38, p. 435. + + News Repert. f. Pharm., 18, 356. + + Journ. Chem. Soc. 1876, i, p. 112. + + Bericht. d. Deutsch. Chem. Gess. ix, p. 1023. + + Viertelj. f. Ger. Med. 1881, p. 193. + + Zeit. f. Anal. Chem. von Fresenius, xii, p. 4. + + +Flour and Bread. + + Analyst, June, 1878; ibid, Jan., 1882; ibid, 1878, No. 28; ibid, vi, + 1879, p. 126; ibid, iii, pp. 274, 355. + + Chem. News, 1873, 1879, xxxix, p. 80. + + Dingl. Pol. Journ. bd. 209. + + Journ. Pharm. [4] iv, 108. + + Chem. Centr'b't, 1877, 585. + + Pharm. Journ. xiii, 857. + + Journ. Chem. Med. 1878, p. 240. + + An. d. Chem. u. Pharm, bd. 10, 45 u. 101. + + Journ. f. Pract. Chem. xcix, 296; ciii, 65, 193, 233, 273. + + Zeit. Anal. Chem. 1878, p. 440; ibid, 1879, vol. xviii, p. 120. + + Chem. Soc. Jour. xxxv, p. 610. + + Jour. d'Hygiène, May, 1878. + + Pharm. Jour. Trans. 1876, cccxii, 1001. + + Pharmacographia, 1879, p. 62. + + Sanitary Engineer, vol. v, p. 66. + + +Tea. + + Pharm. Journ. 1873; 3d series, 1874. + + Chem. News, xxx, 1874 (Allen); xxx, 125; xxviii, 186. + + Journ. Pharm. [2] xxvi, 63; xii, 234, 229. + + Analyst, June, 1877; 1876 (Wigner). + + Journ. Chem. Soc. 1875, 385, 1217; ix, 321, 33; 1858. + + Journ. f. Pract. Chem. x, 273; xciv, 65; li, 401. + + Bull. Soc. Chim. [2] xxvii, 199. + + Journ. de Pharm. d'Anvers, 1876, 121. + + Journ. Pharm. et Chim. 3 série, 1856, xxiv, 228. + + Repert. de Pharm. 1856, vii, p. 117. + + Journ. Chim. Méd. 2 série, 1844, x, 459; 1844, 24. + + Ann. Chem. Pharm. xxvi, 244; xxix, 271; xxxvi, 93. + + Ann. Chem. Pharm. lxxxii, 197; cxii, 96; i, 19; 1, 231; lxiii, 201; + lxix, 120; lxxi; cxviii, 151. + + Ann. Chem. xxv, 63. + + Med. Press and Circular, 1871, p. 415. + + Kastu. Arch. vii, 266. + + Deut. Chem. Ges. Ber. ix, 1312. + + Parliamentary papers, 1871. + + Mag. Pharm. xix, 45. + + Ann. Chim. Phys. [3] xi, 138. + + Schweigg, Journ. Chem. Phys. lxi, 487; lxiv, 372. + + Phil. Mag. J. xxiii, 426; xiii, 21. + + +Milk. + + Analyst, 1876, Jan. and May; 1877, p. 82; No. 21; Sept., Dec.; 1878, + Jan.; p. 249; 1880, Mar. + + Chem. News, 1879. + + Journ. Chem. Soc. clxxxix, Sept., 1878. + + Comptes Rendus, t. 82, 1876. + + Ann. Chem. Pharm. lxi, 221. + + Milch Zeit. 1870, 1884. + + +Wine and Beer. + + Analyst, 1877, pp. 26, 99, 146, 148. + + Ann. Chim. Phys. [5] ii, pp. 233-289. + + Bull. Soc. Chim. [2] xxv. + + Deut. Chem. Ges. Ber. ix, 1900. + + Comptes Rendus, lxxxiv, 348. + + Journ. Chim. Méd. t. ix, p. 495. + + Arch. Pharm. [3] v. 25, 23, bd. 185, p. 225. + + Chem. Soc. Journ. ii, 1877, p. 372. + + Ann. d'Hyg. et Méd. Lég. 1861, xvii, pp. 33, 430. + + +Vinegar. + + Analyst, iii, 1878, p. 268; i, 1877, p. 105. + + Ann. d'Hyg. et Méd. Lég. 2 sér. t. xii. + + Pharm. Journ., Jul. 3, 1875. + + * * * * * + +Within the last few years the subject of food-adulteration has been so +prominently brought before the public that, in many instances, the +various State Boards of Health have commissioned their chemists to +furnish reports on this subject. These may be found in the annual +publications of the same, notably in the volumes issued by the +Massachusetts, Michigan, New Jersey, and New York State Boards of +Health. It may also be mentioned in this connection that the _Sanitary +Engineer_ of New York, the _Analyst_ of London, the _Zeitschrift für +Untersuchung von Lebensmitteln_, Eichstatt, and the _Zeitschrift gegen +Verfälschung der Lebensmittel_, Leipzig, are journals devoted to the +consideration of adulterations and the more recent methods employed for +their detection. + + J. P. B. + + + + +INDEX. + + + A. + + Acetic Acid, 49, 89 + + Acids, 46, 95 + Acetic, 49, 89 + Boric, 90 + Formic, 89 + Hydriodic, 90 + Hydrobromic, 90 + Hydrochloric, 46 + Hydrocyanic, 50 + Hydrofluoric, 88 + Hydrosulphuric, 91 + Nitric, 47, 88 + Oxalic, 49, 88, 89, 95 + Phosphoric, 48, 90, 95 + Phosphorous, 45 + Sulphuric, 47, 89, 95 + + Aconitine, 79 + + Alcoholmeter (Gay-Lussac's), 145 + + Alkalies, 32, 93 + Ammonia, 50 + Baryta, 54 + Lime, 53 + Potassa, 53 + Soda, 53 + Strontia, 54 + + Alkaloids, 65 + Aconitine, 79 + Aniline, 75 + Aricine, 77 + Atropine, 80 + Beberine, 76 + Brucine, 78 + Cinchonine, 78 + Codeine, 80 + Colchicine, 80 + Conine, 75 + Delphine, 78 + Digitaline, 80 + Emetine, 80 + Morphine, 80 + Narcotine, 77 + Nicotine, 75 + Papaverine, 77 + Picrotoxine, 80 + Quinine, 77 + Solanine, 79 + Strychnine, 78 + Veratrine, 77 + + Alkaloids, separation of, by Stas's method, 65 + Separation of, by Otto's method, 69 + Separation of, by v. Uslar and Erdman's method, 70 + Separation of, by Rodgers & Girdwood's method, 71 + Separation of, by Prollius's method, 72 + Separation of, by Graham & Hofman's method, 73 + Separation of, by Dialysis, 74 + + Alkaloids, identification of, 74 + + Alloys, examination of, 112 + + Alum in flour and bread, 126 + + Aniline, 75 + + Antimony, 30, 62, 93 + Detection of, by Flandin and Danger's method, 32 + Detection of, by Naquet's method, 34 + + Aricine, 77 + + Arsenic, 17, 60, 93 + Detection of, by the method used prior to Marsh's test, 17 + Detection of, by Marsh's test, 21 + Detection of, by Raspail's test, 29 + Detection of, by Reinsch's test, 30 + + Arsenic, estimation of, 21 + + Ashes, examination of, 104 + + Atropine, 80 + + + B. + + Barley meal in flour, 117 + + Baryta, 54 + + Barreswil's test for milk, 140 + + Berberine, 76 + + Bicarbonate of soda in milk, 141 + + Bismuth, 62 + + Blood stains, detection of, 150 + + Bleaching of hair, 98 + + Boric acid, 90 + + Boutigny's examination of fire-arms, 100 + + Bromine, 55, 90, 93, 94 + + Brücke's test for blood stains, 152 + + Brucine, 78 + + Buckwheat in flour, 117, 120 + + + C. + + Cadmium, 63 + + Carbonate of lime and magnesia in flour, 125 + + Cerebral substances in milk, 142 + + Chalk in milk, 141 + + Chlorine, 54 + + Chromium, 64 + + Cinchonine in sulphate of quinine, 149 + + Codeine, 80 + + Conine, 75 + + Coins, examination of, 112 + + Colchicine, 80 + + Copper, 62, 63 + + Corn meal in flour, 117, 120 + + + D. + + Darnel in flour, 121 + + Delphine, 78 + + Determinative tests for poisons, 94 + + Digitaline, 80 + + Dusart's test for phosphorus, 40 + + Dialysis, 15, 74 + + Dyeing of hair, 97 + + + E. + + Emetine, 80 + + Emulsion of almonds in milk, 141 + + + F. + + Fire-arms, examination of, 100 + Weapons provided with a flint, 100 + Weapons not provided with a flint, 103 + + Fixed Oils, examination of, 128 + Hempseed, 130 + Olive, 128 + + Flandin and Danger's test for antimony, 32 + + Flandin and Danger's test for mercury, 37 + + Food (flour and bread), 114 + Examination of the gluten, 116 + Examination of the starch, 118 + Examination of the ash, 124 + + Formic acid, 89 + + Fresenius & Neubauer's test for phosphorus, 42 + + + G. + + Galactoscope, 138 + + Graham and Hofman's method for alkaloids, 73 + + Ground bones in bread and flour, 125 + + Gum arabic in milk, 141 + + Gum tragacanth in milk, 141 + + + H. + + Hæmin crystals, 150 + + Hair, examination of, 96 + + Hempseed oil, 130 + + Hoppe-Seyler's test for blood, 151 + + Hydriodic acid, 90 + + Hydrobromic acid, 90 + + Hydrochloric acid, 46, 91 + + Hydrocyanic acid, 50 + + Hydrofluoric acid, 88 + + Hydrosulphuric acid, 91 + + + I. + + Iodides, 90, 94 + + Iodine, 56, 94 + + Indicative tests for poisons, 36 + + + L. + + Lactodensimeter, 138 + + Lactometer, 139 + + Lactoscope, 138 + + Lassaigne's test for writings, 107 + + Lead, 57 + + Legumens in flour, 117, 121, 124 + + Lentils in flour, 123 + + Lime, 53 + + Lime in flour, 126 + + Linseed meal in flour, 120 + + + M. + + Macadam's method for alkaloids, 73 + + Magnesia in sulphate of quinine, 148 + + Mannite in sulphate of quinine, 148 + + Marchand's test for milk, 139 + + Marsh's test for arsenic, 21 + + Mercury, 36, 62, 93 + Detection of, by Smithson's pile, 36 + Detection of, by Flandin and Danger's method, 37 + + Metals, 56 + Antimony, 30, 62, 93 + Arsenic, 17, 60, 93 + Bismuth, 62 + Cadmium, 63 + Chromium, 64 + Copper, 62, 63 + Lead, 57 + Mercury, 36, 62, 93 + Silver, 57 + Tin, 56, 61 + Zinc, 64 + + Milk, examination of, 137 + + Mineral substances, in flour and bread, 124 + In milk, 141 + In sulphate of quinine, 148 + + Mistcherlich's test for phosphorus, 40 + + Morphine, 80 + + + N. + + Naquet's test for antimony, 34 + + Narcotine, 77 + + Nicotine, 75 + + Nitric acid, 47, 88 + + + O. + + Oatmeal in flour, 117 + + Oleometer, 128 + + Olive oil, 128 + + Orfila's test for phosphorus, 39 + + Organic matter + Destruction of, by _aqua regia_, 14 + Destruction of, by chlorate of potassa, 13 + Destruction of, by chlorine, 13 + Destruction of, by nitrate of potassa, 10 + Destruction of, by nitric acid, 8 + Destruction of, by potassa and nitrate of lime, 12 + Destruction of, by potassa and nitric acid, 12 + Destruction of, by sulphuric acid, 9 + + Otto's method for alkaloids, 69 + + Oxalic acid, 49, 88, 89, 95 + + + P. + + Papaverine, 77 + + Payen's test for vinegar, 147 + + Phosphoric acid, 48, 90, 95 + + Phosphorous acid, 45 + + Phosphorus, 39, 95 + Detection of, by Orfila's method, 39 + Detection of, by Mistcherlich's method, 40 + Detection of, by Dusart's method, 40 + Detection of, by Fresenius and Neubauer's method, 42 + Estimation of, 45 + + Picrotoxine, 80 + + Plaster in flour, 126 + + Poisons, detection of + In cases where no clew exists, 85 + In cases where a clew exists, 17 + Destruction of the organic matter, 8 + Indicative tests, 86 + Determinative tests, 94 + + Potato meal in flour, 118 + + Potassa, 53, 93 + + Prollius' method for alkaloids, 72 + + Prussic acid, 50 + + + Q. + + Quinine, 77 + + + R. + + Raspail's test for arsenic, 29 + + Reinsch's test for arsenic, 30 + + Reveil's test for vinegar, 148 + + Rice meal in flour, 120 + + Robin's method for spermatic stains, 160 + + Rodgers and Girdwood's method for alkaloids, 71 + + Rye meal in flour, 117, 120 + + + S. + + Salicine in sulphate of quinine, 148 + + Sand in flour, 125 + + Silver, 57 + + Smithson's pile, 36 + + Soda, 53, 92, 93 + + Solanine, 79 + + Spermatic stains, detection of, 158 + + Spermatozoa, 159 + + Starch in sulphate of quinine, 148 + + Stearic acid in sulphate of quinine, 148 + + Stas's method for alkaloids, 65 + + Strychnine, 78 + + Sugar in milk, 142 + + Sugar in sulphate of quinine, 148 + + Sulphate of copper in bread, 127 + + Sulphate of quinidine in sulphate of quinine, 149 + + Sulphate of quinine, examination of, 148 + + Sulphuretted hydrogen, 91 + + Sulphuric acid, 47, 89, 95 + + Sympathetic inks, tests for, 110 + + + T. + + Tea, 130 + + Tin, 56, 61 + + + U. + + v. Uslar and Erdman's method for alkaloids, 70 + + + V. + + Veratrine, 77 + + Vinegar, examination of, 147 + + + W. + + Wines, examination of, 142 + + Writings, examination of, 105 + + + Z. + + Zinc, 64 + + + + + BECKER & SONS, + MANUFACTURERS OF + Balances and Weights of Precision, + FOR + + [Illustration] + + Chemists, Assayers, Jewelers, Druggists, + _And in general for every use where accuracy is required_, + No. 6 Murray St., New York. + +Every Balance and Set of Weights leaving this establishment is +guaranteed to be accurately adjusted, as represented in our Price List. + +--> Our Illustrated Price List mailed on application. + + + + +CATALOGUE + +OF THE + +SCIENTIFIC, MILITARY, AND NAVAL + +PUBLICATIONS + +OF + +D. VAN NOSTRAND, + +23 Murray Street and 27 Warren Street, New York. + + + +*ABBOT, Maj. HENRY L.--Siege Artillery against Richmond.* + + Illustrated. 8vo, cloth $3 50 + +*ADAMS, J. 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C.--Manual for Engineering Troops.* + + Consisting of--Part I. Ponton Drill; II. Practical Operations of a + Siege; III. School of the Sap; IV. Military Mining; V. Construction of + Batteries. With 16 plates and numerous wood-cut illustrations. 12mo, + half morocco 1 50 + +*DUBOIS, A. J.--The New Method of Graphical Statics.* + + With 60 illustrations. 8vo, cloth 1 50 + +*DUFOUR, Gen. G. H.--The Principles of Strategy and Grand Tactics.* + + Translated from the French, by William P. Craighill, U. S. Engineers, + from the last French edition. Illustrated. 12mo, cloth 1 50 + +*DURYEA, Col. A.--Standing Orders of the Seventh Regiment National + Guards.* + + New edition. 16mo, cloth 50 + +*EASSIE, P. B.--Wood and its Uses.* + + A Hand-Book for the use of Contractors, Builders, Architects, + Engineers, and Timber Merchants. Upwards of 250 illustrations. 8vo, + cloth 1 50 + +*EDDY, Prof. H. T.--Researches in Graphical Statics.* + + Embracing New Constructions in Graphical Statics, a New General Method + in Graphical Statics, and the Theory of Internal Stress in Graphical + Statics. 8vo, cloth 1 50 + +*ELIOT, Prof. C. W., and STORER, Prof. F. H.--A Compendious Manual of + Qualitative Chemical Analysis.* + + Revised with the co-operation of the authors. By Prof. William R. + Nichols. Illustrated. 12mo, cloth 1 50 + +*ELLIOT, Maj. GEO. H., U. S. E--European Light-House Systems.* + + Being a Report of a Tour of Inspection made in 1873. 51 engravings and + 21 wood-cuts. 8vo, cloth 5 00 + +*ENGINEERING FACTS AND FIGURES.* + + An Annual Register of Progress in Mechanical Engineering and + Construction for the years 1863-64-65-66-67-68. Fully illustrated 6 + vols. 18mo, cloth (each volume sold separately), per vol: 2 50 + +*FANNING, J. T.--A Practical Treatise on Water-Supply Engineering.* + + Relating to the Hydrology, Hydrodynamics, and Practical Construction + of Water-Works in North America. Third edition. With numerous tables + and 180 illustrations. 650 pages. 8vo, cloth 5 00 + +*FISKE, Lieut. BRADLEY A., U. S. N.--Electricity in Theory and Practice; + or, The Elements of Electrical Engineering.* + + 8vo, cloth 2 50 + +*FOSTER, Gen. J. G., U. S. A.--Submarine Blasting in Boston Harbor, + Massachusetts.* + + Removal of Tower and Corwin Rocks. Illustrated with seven plates. 4to, + cloth 3 50 + +*FOYE, Prof. J. C.--Chemical Problems.* + + With brief Statements of the Principles involved. Second edition, + revised and enlarged. 16mo, boards 50 + +*FRANCIS, JAS. B., C. E.--Lowell Hydraulic Experiments:* + + Being a selection from Experiments on Hydraulic Motors, on the Flow of + Water over Weirs, in Open Canals of Uniform Rectangular Section, and + through submerged Orifices and diverging Tubes. Made at Lowell, + Massachusetts. Fourth edition, revised and enlarged, with many new + experiments, and illustrated with twenty-three copperplate engravings. + 4to, cloth 15 00 + +*FREE-HAND DRAWING.* + + A Guide to Ornamental Figure and Landscape Drawing. By an Art Student. + 18mo, boards 0 50 + +*FRY, Brig.-Gen. JAMES B.--Army Sacrifices; or, Briefs from Official + Pigeon-Holes.* + + Sketches based on Official Reports, grouped together for the purpose + of illustrating the Services of the Regular Army of the United States + on the Indian Frontier. 16mo. 1 25 + +---- *History of Brevet Rank.* + + The History and Legal Effects of Brevets in the Armies of Great + Britain and the United States, from the origin in 1692 until the + present time. Crown 8vo, extra cloth 3 00 + +*GILLMORE, Gen. Q. A.--Treatise on Limes, Hydraulic Cements, and + Mortars.* + + Papers on Practical Engineering, U. S. Engineer Department, No. 9, + containing Reports of numerous Experiments conducted in New York City + during the years 1858 to 1861, inclusive. With numerous illustrations. + 8vo, cloth 4 00 + +---- *Practical Treatise on the Construction of Roads, Streets, and + Pavements.* + + With 70 illustrations. 12mo, cloth 2 00 + +---- *Report on Strength of the Building-Stones in the United States, + etc.* + + 8vo, illustrated, cloth 1 50 + +---- *Coignet Beton and other Artificial Stone.* + + 9 plates, views, etc. 8vo, cloth 2 50 + +---- *Fort Sumter.* + + Official Report of Operations against the Defences of Charleston + Harbor, 1863. Comprising the descent upon Morris Island, the + Demolition of Fort Sumter, and the siege and reduction of Forts Wagner + and Gregg. With 76 lithographic plates, views, maps, etc. 8vo, cloth + 7 50 + Half Russia 12 00 + +---- *Supplementary Report on Fort Sumter.* + + Supplementary Report to the Engineer and Artillery Operations against + the Defences of Charleston Harbor in 1863. With 7 lithographed maps + and views. 8vo, cloth 3 50 + +---- *Siege and Reduction of Fort Pulaski, Georgia.* + + Illustrated by maps and views. 8vo, cloth 2 50 + +*GOODEVE, T. M.--A Text-Book on the Steam-Engine.* + + 143 illustrations. 12mo, cloth 2 00 + +*GORDON, J. E. H.--Four Lectures on Static Induction.* + + 12mo, cloth 80 + +*GRAFTON, Capt. HENRY D.--A Treatise on the Camp and March.* + + With which is connected the Construction of Field-Works and Military + Bridges. 12mo, cloth 75 + +*GREENER, WM., R. C. E.--A Treatise on Rifles, Cannon, and Sporting + Arms.* + + 8vo, cloth 4 00 + Full calf 6 00 + +*GRUNER, M. L.--The Manufacture of Steel.* + + Translated from the French, by Lenox Smith, with an appendix on the + Bessemer process in the United States, by the translator. Illustrated. + 8vo, cloth 3 50 + +*GUIDE TO WEST POINT and the U. S. Military Academy.* + + With maps and engravings. 18mo, flexible cloth 1 00 + +*HALF-HOURS WITH MODERN SCIENTISTS.--Lectures and Essays,* + + By Professors Huxley, Barker, Stirling, Cope, Tyndall, Wallace, + Roscoe, Huggins, Lockyer, Young, Mayer, and Reed. Being the University + Series bound up. With a general introduction by Noah Porter, President + of Yale College. 2 vols. 12mo, cloth, illustrated 2 50 + +*HAMERSLY, LEWIS B.--The Records of Living Officers of the U. S. Navy + and Marine Corps.* + + Compiled from Official Sources. Third edition. Cloth, 8vo. 2 50 + +*HAMILTON, W. G.--Useful Information for Railway Men.* + + Sixth edition, revised and enlarged. 562 pages, pocket form. Morocco, + gilt 2 00 + +*HARRISON, Col. WALTER.--Pickett's Men.* + + A Fragment of War History. With portrait of Gen. Pickett. 12mo, cloth + 1 25 + +*HARRISON, W. B.--The Mechanic's Tool Book,* + + With Practical Rules and Suggestions for Use of Machinists, + Iron-Workers, and others. Illustrated with 44 engravings. 12mo, cloth + 1 50 + +*HARWOOD, A. A.--Naval Courts-Martial.* + + Law and Practice of United States Naval Courts-Martial. Adopted as a + Text-Book at the U. S. Naval Academy. 8vo, law-sheep 3 00 + +*HASKINS, C. H.--The Galvanometer and its Uses.* + + A Manual for Electricians and Students. Second edition. 12mo, morocco + 1 50 + +*HAUPT, Brig.-Gen. HERMAN.--Military Bridges.* + + For the Passage of Infantry, Artillery, and Baggage-Trains; with + suggestions of many new expedients and constructions for crossing + streams and chasms. Including also designs for Trestle and Truss + Bridges for Military Railroads, adapted specially to the wants of the + Service of the United States. Illustrated by 69 lithographic + engravings. 8vo, cloth 6 50 + +*HEAD, Capt. GEORGE E.--A New System of Fortifications.* + + Illustrated. 4to, paper 50 + +*HEAVY ARTILLERY TACTICS: 1863.* + + Instructions for Heavy Artillery; prepared by a Board of Officers, for + the use of the Army of the United States. With service of a gun + mounted on an iron carriage, and 39 plates. 12mo, cloth 1 00 + +*HENRICI, OLAUS.--Skeleton Structures, especially in their application + to the Building of Steel and Iron Bridges.* + + With folding plates and diagrams. 8vo, cloth 1 50 + +*HENRY, GUY V.--Military Record of Civilian Appointments in the United + States Army.* + + 2 vols. 8vo, cloth 10 00 + +*HETH, Capt. HENRY.--System of Target Practice.* + + For the Use of Troops when armed with the Musket, Rifle-Musket, Rifle, + or Carbine. Prepared principally from the French. 18mo, cloth 50 + +*HEWSON, WM.--Principles and Practice of Embanking Lands from River + Floods, as applied to the Levees of the Mississippi.* + + 8vo, cloth 2 00 + +*HOLLEY, ALEXANDER L.--A Treatise on Ordnance and Armor.* + + Embracing descriptions, discussions, and professional opinions + concerning the materials, fabrication, requirements, capabilities, and + endurance of European and American Guns, for Naval, Sea-Coast, and + Iron-Clad Warfare, and their Rifling, Projectiles, and Breech-Loading; + also, results of experiments against armor, from official records, + with an appendix referring to Gun-Cotton, Hooped Guns, etc., etc. 948 + pages, 493 engravings, and 147 Tables of Results, etc. 8vo, half roan + 7 50 + Half Russia 10 00 + +---- *Railway Practice.* + + American and European Railway Practice in the economical Generation of + Steam, including the Materials and Construction of Coal-burning + Boilers, Combustion, the Variable Blast, Vaporization, Circulation, + Superheating, Supplying and Heating Feed-water, etc., and the + Adaptation of Wood and Coke-burning Engines to Coal-burning; and in + Permanent Way, including Road-bed, Sleepers, Rails, Joint-fastenings, + Street Railways, etc., etc. With 77 lithographed plates. Folio, cloth + 12 00 + +*HOTCHKISS, JED., and ALLAN, WILLIAM.--The Battle-Fields of Virginia.* + + Chancellorsville, embracing the Operations of the Army of Northern + Virginia, from the First Battle of Fredericksburg to the Death of + Lt.-Gen. T. J. Jackson. Illustrated with five maps and portrait of + Stonewall Jackson. 8vo, cloth 3 50 + +*HOWARD, C. R.--Earthwork Mensuration on the Basis of the Prismoidal + Formulæ.* + + Containing simple and labor-saving method of obtaining Prismoidal + Contents directly from End Areas. Illustrated by Examples, and + accompanied by Plain Rules for Practical Uses. Illustrated. 8vo, + cloth 1 50 + +*HUNTER, Capt. R. F.--Manual for Quartermasters and Commissaries.* + + Containing Instructions in the Preparation of Vouchers, Abstracts, + Returns, etc. 12mo, cloth 1 00 + Flexible morocco 1 50 + +*INDUCTION-COILS.--How Made and How Used.* + + 63 illustrations. 16mo, boards 50 + +*INSTRUCTIONS FOR FIELD ARTILLERY.* + + Prepared by a Board of Artillery Officers. To which is added the + "Evolutions of Batteries." Translated from the French by Brig.-Gen. R. + Anderson, U. S. A. 122 plates. 12mo, cloth 1 00 + +*ISHERWOOD, B. F.--Engineering Precedents for Steam Machinery.* + + Arranged in the most practical and useful manner for Engineers. With + illustrations. Two volumes in one. 8vo, cloth 2 50 + +*IVES, Lieut. R. A.--Military Law.* + + A Treatise on Military Law, and the Jurisdiction, Constitution, and + Procedure of Military Courts. With a Summary of the Rules of Evidence + as applicable to such Courts. 400 pages. 8vo, law-sheep 4 00 + +*JANNETTAZ, EDWARD--A Guide to the Determination of Rocks:* + + Being an Introduction to Lithology. Translated from the French by G. + W. Plympton, Professor of Physical Science at Brooklyn Polytechnic + Institute. 12mo, cloth 1 50 + +*JEFFERS, Capt. W. N., U. S. N.--Nautical Surveying.* + + Illustrated with 9 copperplates and 31 wood-cut illustrations. 8vo, + cloth 5 00 + +*JOMINI, Gen. BARON DE.--Campaign of Waterloo.* + + The Political and Military History of the Campaign of Waterloo. + Translated from the French by Gen. S. V. Benét. Third edition. 12mo, + cloth 1 25 + +---- *Treatise on Grand Military Operations.* + + Illustrated by a Critical and Military History of the Wars of + Frederick the Great. With a Summary of the Most Important Principles + of the Art of War. Illustrated by maps and plans. Translated from the + French by Col. S. B. Holabird, U. S. A. 2 vols. 8vo and Atlas. Cloth + 15 00 + Half calf or morocco 21 00 + Half Russia 22 50 + +*JONES, H. CHAPMAN.--Text-Book of Experimental Organic Chemistry for + Students.* + + 18mo, cloth 1 00 + +*JOYNSON, F. H.--The Metals used in Construction: Iron, Steel, Bessemer + Metal, etc., etc.* + + Illustrated. 12mo, cloth 75 + +---- *Designing and Construction of Machine Gearing.* + + Illustrated. 8vo, cloth 2 00 + +*KANSAS CITY BRIDGE, THE.* + + With an account of the Regimen of the Missouri River, and a + description of the methods used for Founding in that River. By O. + Chanute, Chief-Engineer, and George Morrison, Assistant-Engineer. + Illustrated with five lithographic views and twelve plates of plans. + 4to, cloth 6 00 + +*KELTON, Gen. J. C.--New Bayonet Exercise.* + + A New Manual of the Bayonet, for the Army and Militia of the United + States. With 40 beautifully engraved plates. Fifth edition. Revised. + 12mo, cloth 2 00 + +*KING, W. H.--Lessons and Practical Notes on Steam,* + + The Steam-Engine, Propellers, etc., etc., for young Marine Engineers, + Students, and others. Revised by Chief-Engineer J. W. King, U. S. + Navy. Nineteenth edition, enlarged. 8vo, cloth 2 00 + +*KIRKWOOD, JAS. P.--Report on the Filtration of River Waters for the + supply of Cities,* + + As practised in Europe, made to the Board of Water Commissioners of + the City of St. Louis. Illustrated by 30 double-plate engravings. 4to, + cloth 15 00 + +*LARRABEE, C. S.--Cipher and Secret Letter and Telegraphic Code, with + Hogg's Improvements.* + + The most perfect secret code ever invented or discovered. Impossible + to read without the key. 18mo, cloth 1 00 + +*LAZELLE, Capt. H. M., U. S. A.--One Law in Nature.* + + A New Corpuscular Theory, comprehending Unity of Force, Identity of + Matter and its Multiple Atom Constitution; applied to the Physical + Affections, or Modes of Energy. 12mo. 1 50 + +*LECOMTE, FERDINAND.--The War in the United States.* + + A Report to the Swiss Military Department. Translated from the French + by a Staff Officer. 12mo, cloth 75 + +*LE GAL, Col. EUGENE.--School of the Guides.* + + Designed for the use of the Militia of the United States. 16mo, cloth + 60 + +*LENDY, Capt.--Maxims and Instructions on the Art of War.* + + A Practical Military Guide for the use of Soldiers of all Arms and of + all Countries. Translated from the French. 18mo, cloth 75 + +*LEVY, Com. U. P.--Manual of Internal Rules and Regulations for + Men-of-War.* + + Third edition, revised and enlarged. 18mo, flexible cloth 30 + +*LIEBER, FRANCIS, LL.D.--Instructions for Armies.* + + Instructions for the Government of Armies of the United States in the + Field. 12mo, paper 25 + +*LIPPITT.--Special Operations of War.* 12mo, cloth 1 00 + +---- *Field Service in War.* 12mo, cloth 1 00 + +---- *Tactical Use of the Three Arms.* 12mo, cloth 1 00 + +---- *Intrenchments.* 12mo, cloth 1 25 + +*LOCK, C. G., WIGNER, G. W., and HARLAND, R. H.--Sugar Growing and + Refining.* + + Treatise on the Culture of Sugar-Yielding Plants, and the Manufacture + and Refining of Cane, Beet, and other sugars. 8vo, cloth, illustrated + 12 00 + +*LOCKWOOD, THOS. D.--Electricity, Magnetism, and Electro-Telegraphy.* + + A Practical Guide for Students, Operators, and Inspectors. 8vo, cloth + +*LORING, A. E.--A Hand-Book on the Electro-Magnetic Telegraph.* + + Paper boards 0 50 + cloth 75 + Morocco 1 00 + +*LUCE, Capt. S. B.--Seamanship.* + + For the use of the United States Naval Academy. Fourth edition. Crown + 8vo, revised and improved, illustrated by 89 full-page copperplate + engravings, half roan 7 50 + + --> Text-Book at the U. S. Naval Academy, Annapolis. + +---- *Naval Light Artillery.* + + By Lieut. W. H. Parker, U. S. N. Third edition, revised by Capt. S. B. + Luce, Assistant Instructor of Gunnery and Tactics at the U. S. Naval + Academy. 22 plates. 8vo, cloth 3 00 + +*MacCORD, Prof. C. W.--A Practical Treatise on the Slide-Valve by + Eccentrics,* + + Examining by methods the action of the Eccentric upon the Slide-Valve, + and explaining the practical processes of laying out the movements, + adapting the valve for its various duties in the steam-engine. Second + edition. Illustrated. 4to, cloth 2 50 + +*McCLELLAN, Gen. GEO. B.--Report of the Army of the Potomac,* + + Of its operations while under his command. With maps and plans. 8vo, + cloth 1 00 + Paper 50 + +*McCULLOCH, Prof. R. S.--Elementary Treatise on the Mechanical Theory of + Heat, and its application to Air and Steam Engines.* + + 8vo, cloth 3 50 + +*MANUAL OF BOAT EXERCISE.* + + At the U. S. Naval Academy, designed for the practical instruction of + the Senior Class in Naval Tactics. 18mo, flexible cloth 50 + +*MENDELL, G. H.--Military Surveying.* + + A Treatise on Military Surveying, Theoretical and Practical, including + a description of Surveying Instruments. With 70 wood-cut + illustrations. 12mo, cloth 1 50 + +*MERRILL, Col. WM. E., U. S. A.--Iron Truss Bridges for Railroads.* + + The method of calculating strains in Trusses, with a careful + comparison of the most prominent Trusses, in reference to economy in + combination, etc., etc. Illustrated. 4to, cloth 5 00 + +*MICHAELIS, Capt. O. E.--The Le Boulenge Chronograph.* + + With three lithographed folding plates of illustrations. 4to, + illustrated, cloth 3 00 + +*MICHIE, Prof. P. S.--Elements of Wave Motion relating to Sound and + Light.* + + Text-Book for the U. S. Military Academy. 8vo, cloth, illustrated + 5 00 + +*MINIFIE, WM--Mechanical Drawing.* + + A Text-Book of Geometrical Drawing for the use of Mechanics and + Schools, in which the Definitions and Rules of Geometry are familiarly + explained; the Practical Problems are arranged, from the most simple + to the more complex, and in their description technicalities are + avoided as much as possible. With illustrations for Drawing Plans, + Sections, and Elevations of Railways and Machinery; an Introduction to + Isometrical Drawing, and an Essay on Linear Perspective and Shadows. + Illustrated with over 200 diagrams engraved on steel. Ninth edition. + With an Appendix on the Theory and Application of Colors. 8vo, cloth + 4 00 + + "It is the best work on drawing that we have ever seen, and is + especially a text-book of Geometrical Drawing for the use of Mechanics + and Schools. No young Mechanic, such as a Machinist, Engineer, + Cabinet-maker, Millwright, or Carpenter, should be without + it."--_Scientific American._ + + +---- *Geometrical Drawing.* + + Abridged from the octavo edition, for the use of schools. Illustrated + with 48 steel plates. Fifth edition. 12mo, cloth 2 00 + +*MODERN METEOROLOGY.* + + A Series of Six Lectures, delivered under the auspices of the + Meteorological Society in 1878. Illustrated. 12mo, cloth 1 50 + +*MONROE, Col. J.--Light Infantry Company and Skirmish Drill.* + + Bayonet Fencing; with a Supplement on the Handling and Service of + Light Infantry. 32mo, cloth 75 + +*MOORE, FRANK--The Rebellion Record.* + + Containing a full and concise Diary of Events from December, 1860, to + the close of the War of the Rebellion, with Official Reports of State + Officers and Narratives of all the Battles and Skirmishes that + occurred. Complete in twelve volumes royal 8vo. Illustrated with 158 + steel engraved Portraits of distinguished Generals and Prominent Men, + together with numerous Maps and Plans of Battles. Price in cloth + 60 00 + Library sheep 72 00 + Half calf, antique 78 00 + Half morocco 78 00 + Half Russia 84 00 + +---- *Portrait Gallery of the War, Civil, Military, and Naval.* + + A Biographical Record. Illustrated with 60 fine portraits on steel. 1 + vol. 8vo, cloth 6 00 + Half calf 7 50 + +*MORRIS, E.--Easy Rules for the Measurement of Earthworks, by Means of + the Prismoidal Formula.* + + 78 illustrations. 8vo, cloth 1 50 + +*MORRIS, Gen. WM. H.--Field Tactics for Infantry.* + + Illustrated. 18mo, cloth 75 + +---- *Infantry Tactics.* + + 2 vols. 24mo. 2 00 + 2 vols. in one, cloth 1 50 + + + + +Transcriber's Notes: + +The following corrections which did not concern obvious printer's errors +have been made to the text. + + -In the Table of Content, the formatting of the entry for "Dialysis" + was changed in order to indicate that this part is a section of the + chapter "Methods of Destruction of the Organic Substances" + + -"treated with "_mélaïnocome_"" was: "treated with "melaniocome"" + + -The sentence "M. Salleron offers for sale a small apparatus + (Fig. 20)" wrongly referred to Fig. 16. + + -"If the crystals originate from fresh blood, they appear as + represented in Fig. 21; crystals from old blood are represented in + Fig. 22." wrongly referred to Fig. 17 and 18; the same was the case + in "The fluid is examined from time to time under the microscope: + when it is sufficiently concentrated, crystals, presenting the + appearance represented in Figs. 21 or 22, will be observed." + + -"an oxidizing body" was: "an oxydizing body" + + -"condenser" was: "condensor" + + -"areometer (alcoholmeter)" was: "areometer (alcoolmeter)" + + + + + +End of the Project Gutenberg EBook of Legal Chemistry, by J. P. Battershall + +*** END OF THE PROJECT GUTENBERG EBOOK 44048 *** |