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| author | Roger Frank <rfrank@pglaf.org> | 2025-10-14 18:45:54 -0700 |
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| committer | Roger Frank <rfrank@pglaf.org> | 2025-10-14 18:45:54 -0700 |
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diff --git a/44541-h/44541-h.htm b/44541-h/44541-h.htm new file mode 100644 index 0000000..924c8b3 --- /dev/null +++ b/44541-h/44541-h.htm @@ -0,0 +1,5195 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> + <head> + <meta http-equiv="Content-Type" content="text/html;charset=UTF-8" /> + <meta http-equiv="Content-Style-Type" content="text/css" /> + <title> + The Project Gutenberg eBook of The Last Link, by Ernst Haeckel. + </title> +<link rel="coverpage" href="images/cover.jpg" /> + <style type="text/css"> + +body { + margin-left: 10%; + margin-right: 10%; +} + +h1 +{ + margin-top: 2em; margin-bottom: 2em; + text-align: center; + font-size: x-large; + font-weight: normal; + line-height: 1.6; +} + h2,h3{ + text-align: center; /* all headings centered */ + clear: both; +} + +.spaced +{ + line-height: 1.5; +} + +.space-above +{ + margin-top: 3em; +} + +p +{ + margin-top: .75em; + text-align: justify; + margin-bottom: .75em; +} + + .small {font-size: small;} + .medium {font-size: medium;} + .large {font-size: large;} + +hr { + width: 33%; + margin-top: 2em; + margin-bottom: 2em; + margin-left: auto; + margin-right: auto; + clear: both; +} + +hr.tb {width: 45%;} +hr.chap {width: 65%} +hr.full {width: 95%;} + +table { + margin-left: auto; + margin-right: auto; +} + + .tdl {text-align: left;} + .tdr {text-align: right;} + .tdc {text-align: center;} + +.pagenum { /* uncomment the next line for invisible page numbers */ + visibility: hidden; + position: absolute; + left: 92%; + font-size: smaller; + text-align: right; +} /* page numbers */ + +.linenum { + position: absolute; + top: auto; + left: 4%; +} /* poetry number */ + +.blockquot { + margin-left: 5%; + margin-right: 10%; +} + +.center {text-align: center;} + +.right {text-align: right;} + +.smcap {font-variant: small-caps;} + +.u {text-decoration: underline;} + +@media handheld + +{.chapter-beginning + {page-break-before: always;} +} + +/* Images */ +.figcenter { + margin: auto; + text-align: center; +} + +/* Footnotes */ +.footnotes {border: dashed 1px;} + +.footnote {margin-left: 10%; margin-right: 10%; font-size: 0.9em;} + +.footnote .label {position: absolute; right: 84%; text-align: right;} + +.fnanchor { + vertical-align: super; + font-size: .8em; + text-decoration: + none; +} + +/* Transcriber's notes */ +.transnote {background-color: #E6E6FA; + color: black; + font-size:smaller; + padding:0.5em; + margin-bottom:5em; + font-family:sans-serif, serif; } + </style> + </head> +<body> +<div>*** START OF THE PROJECT GUTENBERG EBOOK 44541 ***</div> + +<h1>THE LAST LINK</h1> + +<p class="center">OUR PRESENT KNOWLEDGE OF THE + DESCENT OF MAN</p> + +<p class="center space-above"><small>BY</small><br /> +ERNST HAECKEL<br /> +<small>(JENA)</small></p> + +<p class="center space-above"><small>WITH NOTES AND BIOGRAPHICAL SKETCHES<br /> +BY</small><br /> +HANS GADOW, F.R.S.<br /> +<small>(CAMBRIDGE)</small></p> + + +<p class="center space-above">LONDON<br /> +ADAM AND CHARLES BLACK<br /> +1898</p> + +<hr class="chap"/> + +<h2>CONTENTS.</h2> + +<table id="toc" summary="contents"> +<tr> + <td> </td> + <td class="tdr"><span class="smcap">page</span></td> +</tr> +<tr> + <td class="tdl"><big>THE LAST LINK</big></td> + <td class="tdr"> </td> +</tr> +<tr> + <td class="tdl"> INTRODUCTORY</td> + <td class="tdr"><a href="#Page_1">1</a></td> +</tr> +<tr> + <td class="tdl"> COMPARATIVE ANATOMY</td> + <td class="tdr"><a href="#Page_8">8</a></td> +</tr> +<tr> + <td class="tdl"> PALÆONTOLOGY</td> + <td class="tdr"><a href="#Page_20">20</a></td> +</tr> +<tr> + <td class="tdl"> OTHER EVIDENCE</td> + <td class="tdr"><a href="#Page_42">42</a></td> +</tr> +<tr> + <td class="tdl"> STAGES RECAPITULATED</td> + <td class="tdr"><a href="#Page_47">47</a></td> +</tr> +<tr> + <td class="tdl"><big>BIOGRAPHICAL SKETCHES:</big></td> + <td class="tdr"> </td> +</tr> +<tr> + <td class="tdl"> LAMARCK, SAINT-HILAIRE, CUVIER, BAER,</td> + <td class="tdr"> </td> +</tr> +<tr> + <td class="tdl"> MUELLER, VIRCHOW, COPE, KOELLIKER, GEGENBAUR,</td> + <td class="tdr"> </td> +</tr> +<tr> + <td class="tdl"> HAECKEL</td> + <td class="tdr"><a href="#Page_80">80</a></td> +</tr> +<tr> + <td class="tdl">THEORY OF CELLS</td> + <td class="tdr"><a href="#Page_115">115</a></td> +</tr> +<tr> + <td class="tdl">FACTORS OF EVOLUTION</td> + <td class="tdr"><a href="#Page_117">117</a></td> +</tr> +<tr> + <td class="tdl">GEOLOGICAL TIME AND EVOLUTION</td> + <td class="tdr"><a href="#Page_135">135</a></td> +</tr> +</table> + +<hr class="chap" /> +<div class="chapter-beginning"/> + +<h2>NOTE</h2> + + +<p>The address I delivered on August 26 at the +Fourth International Congress of Zoology at +Cambridge, 'On our Present Knowledge of +the Descent of Man,' has, I find, from the +high significance of the theme and the +general importance of the questions connected +with it, excited much interest, and +has led to requests for its publication. +Hence this volume, edited by my friend +Dr. H. Gadow, my pupil in earlier days, +who has not only revised the text, but has +also enriched it by many valuable additions +and notes.</p> + +<p class="right">ERNST HAECKEL.</p> + +<p><small><i>Jena, December, 1898.</i></small></p> + +<p><span class="pagenum"><a name="Page_1" id="Page_1">[Pg 1]</a></span></p> + +<hr class="chap" /> +<div class="chapter-beginning"/> +<h2>THE LAST LINK</h2> + + +<p>At the end of the nineteenth century, the +age of 'natural science,' the department of +knowledge that has made most progress is +zoology. From zoology has arisen the study +of transformism, which now dominates the +whole of biology. Lamarck<a name="FNanchor_1_1" id="FNanchor_1_1"></a><a href="#Footnote_1_1" class="fnanchor">[1]</a> laid its foundation +in 1809, and forty years ago Charles +Darwin obtained for it a recognition which +is now universal. It is not my task to repeat +the well-known principles of Darwinism. I +am not concerned to explain the scientific +value of the whole theory of descent. The +whole of our biological study is pervaded by +it. No general problem in zoology and<span class="pagenum"><a name="Page_2" id="Page_2">[Pg 2]</a></span> +botany, in anatomy and physiology, can be +discussed without the question arising, How +has this problem originated? What are the +real causes of its development?</p> + +<p>This question was almost unknown seventy +years ago, when Charles Darwin, the great +reformer of biology, began his academical +career at Cambridge as a student of theology. +In the same year, 1828, Carl Ernst von +Baer<a name="FNanchor_2_2" id="FNanchor_2_2"></a><a href="#Footnote_2_2" class="fnanchor">[2]</a> published in Germany his classical +work on the embryology of animals, the first +successful attempt to elucidate by 'observation +and reflection' the mysterious origin +of the animal body from the egg, and to +explain in every respect the 'history of the +growing individuality.' Darwin at that time +had no knowledge of this great advance, and +he could not divine that forty years later +embryology would be one of the strongest +supports of his own life's work—of that very +theory of transformism which, founded by +Lamarck in the year of Darwin's birth,<span class="pagenum"><a name="Page_3" id="Page_3">[Pg 3]</a></span> +was accepted with enthusiasm by Charles's +grandfather Erasmus. There is no doubt +that of all the celebrated naturalists of the +nineteenth century Darwin achieved the +greatest success, and we should be justified +in designating the last forty years as the +Age of Darwin.</p> + +<p>In searching for the causes of this unexampled +success, we must clearly separate +three sets of considerations: first, the comprehensive +reform of Lamarck's transformism, +and its firm establishment by the many +arguments drawn from modern biology; +secondly, the construction of the new theory +of selection, as established by Darwin, and +independently by Alfred Wallace (a theory +called Darwinism in the proper sense); +thirdly, the deduction of anthropogeny, that +most important conclusion of the theory of +descent, the value of which far surpasses all +the other truths in evolution.</p> + +<p>It is the third point of Darwin's theory +that I shall discuss here; and I shall discuss<span class="pagenum"><a name="Page_4" id="Page_4">[Pg 4]</a></span> +it chiefly with the intention of examining +critically the evidence and the different +conclusions which at present represent our +scientific knowledge of the descent of man +and of the different stages of his animal +pedigree.</p> + +<p>It is now generally admitted that this +problem is the most important of all biological +questions. Huxley was right when +in 1863 he called it the question of questions +for mankind. The problem which underlies +all others, and is more deeply interesting than +any other, is as to the place which man +occupies in nature and his relations to the +universe of things. 'Whence our race has +come; what are the limits of our power over +nature, and of nature's power over us; to +what goal are we tending—these are the +problems which present themselves anew +and with undiminished interest to every man +born into the world.' This impressive view +was explained by Huxley thirty-five years ago +in his three celebrated essays on 'Evidence<span class="pagenum"><a name="Page_5" id="Page_5">[Pg 5]</a></span> +as to Man's Place in Nature.' The first is +entitled 'On the Natural History of the Man-like +Apes'; the second, 'On the Relations of +Man to the Lower Animals'; the third, 'On +some Fossil Remains of Man.' Darwin himself +felt the burden of these problems as much +as Huxley; but in his chief work, 'On the +Origin of Species,' in 1859, he had purposely +only just touched them, suggesting that the +theory of descent would shed light upon the +origin of man and his history. Twelve years +later, in his celebrated work on 'The Descent +of Man, and Selection in Relation to Sex,' +Darwin discussed fully and ingeniously all +the different sides of this 'question of +questions' from the morphological, historical, +physiological, and psychological points of +view. As early as 1866 I myself had applied +in the <i>Generelle Morphologie der Organismen</i> +the theory of transformism to anthropology, +and had shown that the fundamental law of +biogeny claims the same value for man as for +all the other animals. The intimate causal<span class="pagenum"><a name="Page_6" id="Page_6">[Pg 6]</a></span> +connection between ontogeny and phylogeny, +between the development of the individual and +the history of its ancestors, enables us to gain +a safe and certain knowledge of our ancestral +series. I had at that time distinguished in +this series ten chief degrees of vertebrate +organization. I attributed the highest importance +to the logical connection of anthropogeny +with transformism. If the latter be +true, the truth of the former is absolute. +'Our theory that man is descended from +lower vertebrates, and immediately from apes +or primates, is a case of special <i>deduction</i> +which follows with absolute certainty from the +general <i>induction</i> of the theory of descent.' +The full proof and detailed explanation of +this view was afterwards given in my +'History of Natural Creation,' and especially +in my 'Anthropogeny.'<a name="FNanchor_3_3" id="FNanchor_3_3"></a><a href="#Footnote_3_3" class="fnanchor">[3]</a> Lastly, it has +received an ample scientific and critical +foundation in the third part of my 'Systematic +Phylogeny.'<sup>[3]</sup></p> + +<p><span class="pagenum"><a name="Page_7" id="Page_7">[Pg 7]</a></span></p> +<p>During the forty years which have elapsed +since Darwin's first publication of his theories +an enormous literature, discussing the <i>general +problems</i> of transformism as well as its special +application to man, has been published. In +spite of the wide divergence of the different +views, all agree in one main point: the +natural development of man cannot be separated +from general transformism. There are +only two possibilities. Either all the various +species of animals and plants have been +created independently by supernatural forces +(and in this case the creation of man also is a +miracle); or the species have been produced +in a natural way by transmutation, by adaptation +and progressive heredity (and in this +case man also is descended from other vertebrates, +and immediately from a series of +primates). We are absolutely convinced that +only the latter theory is fully scientific. To +prove its truth, we have to examine critically +the strength of the different arguments claimed +for it.</p> + +<p><span class="pagenum"><a name="Page_8" id="Page_8">[Pg 8]</a></span></p> + +<hr class="chap"/> + +<h2>I.</h2> + + +<p>First, we have to consider the relative +place which comparative anatomy concedes +to man in the 'natural system' of animals, +for the true value of our 'natural classification' +is based upon its meaning as a pedigree. +All the minor and major groups of the system—the +classes, legions, orders, families, genera, +and species—are only different branches of +the same pedigree. For man himself, his +place in the pedigree has been fixed since +Lamarck,<a name="FNanchor_5_5" id="FNanchor_5_5"></a><a href="#Footnote_5_5" class="fnanchor">[5]</a> in 1801, defined the group of +vertebrates. The most perfect<a name="FNanchor_6_6" id="FNanchor_6_6"></a><a href="#Footnote_6_6" class="fnanchor">[6]</a> of these are<span class="pagenum"><a name="Page_9" id="Page_9">[Pg 9]</a></span> +the Mammalia; and at the head of this class +stands the order of Primates, in which Linnæus, +in 1735, united four 'genera'—Homo, +Simia, Lemur, and Vespertilio. If we exclude +the last-named, the Chiroptera of modern +zoology, there remain three natural groups of +Primates—the Lemures, the Simiæ, and the +Anthropi or Hominidæ. This is the classification<span class="pagenum"><a name="Page_10" id="Page_10">[Pg 10]</a></span> +of the majority of zoologists; but if we +compare man with the two chief groups of +monkeys—the Eastern monkeys (or Catarrhinæ) +and the Western or American monkeys +(Platyrrhinæ)—there can be no doubt that the +former group is much more closely related to +man than is the latter. In the natural order +of the Catarrhinæ we find united a long series +of lower and higher forms. The lowest, the +Cynopitheci, appear still closely related to +the Platyrrhinæ and to the Lemures; while, +on the other hand, the tailless apes (Anthropomorphæ) +approach man through their +higher organization. Hence one of our best +authorities on the Primates, Robert Hartmann,<a name="FNanchor_7_7" id="FNanchor_7_7"></a><a href="#Footnote_7_7" class="fnanchor">[7]</a> +proposed to subdivide the whole +order of the Simiæ into three groups:</p> + +<p>(1) Primarii, man together with the other +Anthropomorphæ, or tailless apes; (2) +Simiæ, all the other monkeys; (3) Prosimiæ, +or Lemurs. This arrangement has received<span class="pagenum"><a name="Page_11" id="Page_11">[Pg 11]</a></span> +strong support from the interesting discovery +by Selenka that the peculiar placentation of +the human embryo is the same as in the +great apes, and different from that of all the +other monkeys. Our choice between these +different classifications of Primates is best +determined by the important thesis of Huxley, +in which, in 1863, he carried out a most careful +and critical comparison of all the anatomical +gradations within this order. In my opinion, +this ingenious thesis—which I have called the +Huxleyan Law, or the 'Pithecometra-thesis +of Huxley'—is of the utmost value. It runs +as follows: 'Thus, whatever system of +organs be studied, the comparison of their +modifications in the ape-series leads to one +and the same result—that the structural +differences which separate man from the +gorilla and the chimpanzee are not so great +as those which separate the gorilla from the +lower apes.' If we accept the Huxleyan +law without prejudice, and apply it to the +natural classification of the Primates, we<span class="pagenum"><a name="Page_12" id="Page_12">[Pg 12]</a></span> +must concede that man's place is within the +order of the Simiæ. On examining this +relation with care, and judging with logical +persistence, we may even go a step further. +Instead of the wider conception of 'Simiæ,' +we must use the restricted term of Catarrhinæ, +and our Pithecometra-thesis has then +to be formulated as follows: <i>The comparative +anatomy of all organs of the group of Catarrhine +Simiæ leads to the result that the +morphological differences between man and +the great apes are not so great as are those +between the man-like apes and the lowest +Catarrhinæ</i>. In fact, it is very difficult to +show why man should not be classed with +the large apes in the same zoological family. +We all know a man from an ape; but it is +quite another thing to find differences which +are absolute and not of degree only. Speaking +generally, we may say that man alone +combines the four following features: (1) +Erect walk; (2) extremities differentiated +accordingly; (3) articulate speech; (4) higher<span class="pagenum"><a name="Page_13" id="Page_13">[Pg 13]</a></span> +reasoning power. Speech and reason are +obviously relative distinctions only—the direct +result of more brains and more brain-power, +the so-called mental faculties. The erect walk +is not an absolutely distinguishing characteristic: +the large apes likewise walk on their +feet only, supporting their bodies by touching +the ground with the backs of their hands—in +fact, with their knuckles—and this is a mode +of progression very different from that of the +tailed monkeys, which walk upon the palms +of their hands. There are, however, two +obvious differences in the development of +the muscles. In man alone the gastrocnemius +and the soleus muscle are thick +enough to form the calf of the leg, and +the glutæus maximus is enlarged into the +buttocks. A fourth glutæal muscle occurs +occasionally in man, while it is constantly +present in apes as the so-called musculus +scansorius. Concerning the muscles of the +whole body, we cannot do better than quote +Testut's summary: 'The mass of recorded<span class="pagenum"><a name="Page_14" id="Page_14">[Pg 14]</a></span> +observations upon the muscular anomalies in +man is so great, and the agreement of many +of these with the condition normal in apes is so +marked, that the gap which usually separates +the muscular system of man from that of the +apes appears to be completely bridged over.'</p> + +<p>There are, for example, the muscles of the +ear. In most people the majority, or even +all of them, are no longer movable at will, +while in the apes they are still in use. The +important point, however, is that these +muscles are still present in man, although +often in a reduced condition. They are the +following: (1) Musculus auricularis anterior +or attrahens auris, which is frequently much +reduced and no longer reaches the ear at all, +being then absolutely useless; (2) Musculus +auricularis superior or attollens auris, more +constant than the former; (3) Musculus +auricularis posterior or retrahens auris, likewise +often functional. Occasionally smaller +slips differentiated from these three muscles +are present, and as so-called intrinsic muscles<span class="pagenum"><a name="Page_15" id="Page_15">[Pg 15]</a><br /><a name="Page_16" id="Page_16">[Pg 16]</a></span> +are restricted to the ear itself; their function +is, or was, that of curling up or opening the +external ear.</p> + +<div class="figcenter"><a href="./images/i_0231.jpg"> + <img src="./images/i_0231.jpg" alt="Outlines of the Left Ear"></img></a> +</div> +<p class="center"><span class="smcap">Outlines of the Left Ear of—</span></p> + +<blockquote> +<p><small>1. <i>Lemur macaco</i>; 2. <i>Macacus rhesus</i>, the Rhesus monkey; +3. Cercopithecus, a macaque; 4. human embryo of six months; +5. man, with Darwin's point well retained: the dotted outline is that +of the ear of a baboon; 6. orang-utan (after G. Schwalbe):<a name="FNanchor_8_8" id="FNanchor_8_8"></a><a href="#Footnote_8_8" class="fnanchor">[8]</a> <sup>x</sup> the +original tip of the ear; 7. human ear with the principal muscles.</small></p> +</blockquote> + +<p>In connection with the ear, I may touch +upon another interesting and most suggestive +little feature which is present in many +individuals—namely, 'Darwin's point.' This +is the last remnant of the original tip of the +ear, before the outer, upper, and hinder rim +became doubled up or folded in. It is a +feature quite useless, and absolutely impossible +of interpretation, excepting as the vestige of +such previous ancestral conditions as are +normal in the monkeys.</p> + +<p>In some cases the reduction of muscles +has proceeded further in apes than in man—for +example, the muscles of the little toe. +Another instance is afforded by the coccyx or +vestige of the tail; this is still furnished with +muscles which are now in man, as well as in +the apes, quite useless, and vary considerably +with every sign of degeneration, most so in +the orang-utan.</p> + +<p><span class="pagenum"><a name="Page_17" id="Page_17">[Pg 17]</a></span></p> + +<p>Darwin has mentioned the frequent action +of the 'snarling muscle,' by which, in sneering, +our upper canine teeth are exposed, like those +of a dog prepared to fight.</p> + +<p>Monkeys and apes possess vocal sacs, +especially large in the orang-utan; survivals +of them, although no longer used, persist in +man in the shape of a pair of small diverticula, +the pouches of Morgagni, between the +true and the false vocal cords.</p> + +<p>'In the native Australians, the dental formula +appears least removed from the hypothetical +original type, for in it are still found +complete rows of splendid teeth, with powerfully-developed +canines and molars, the latter +being either uniform, or even increasing in +size, as we proceed backwards, in such a +way that the wisdom tooth is the largest of +the series. This is decidedly a pithecoid +characteristic which is always found in apes. +The upper incisors of the Malay, apart from +their prognathous disposition, have occasionally +a distinctly pithecoid form, their anterior<span class="pagenum"><a name="Page_18" id="Page_18">[Pg 18]</a></span> +surface being convex, and their lingual surface +slightly concave. The ancestors of +Europeans seem to have had the same form +of teeth, for the oldest existing fragments of +skulls from the Mammoth age (<i>e.g.</i>, the jaws +from La Naulette, in Belgium) reveal tooth-forms +which must be classed with those of +the lowest races of to-day.'<a name="FNanchor_9_9" id="FNanchor_9_9"></a><a href="#Footnote_9_9" class="fnanchor">[9]</a></p> + +<p>Now we are able to apply this fundamental +Pithecometra-thesis directly to the classification +of the Primates and to the phylogeny of +man, which is intimately connected with it, +because in this order, as in all the other +groups of animals, the natural system is the +clear expression of true phylogenetic affinity. +Four results follow from our thesis: (1) The +Primates, as the highest legion or order of +mammals, form one natural, monophyletic +group. All the Lemures, Simiæ, and +Homines descend from one common ancestral<span class="pagenum"><a name="Page_19" id="Page_19">[Pg 19]</a></span> +form, from a hypothetical 'Archiprimas.' +(2) The Lemures are the older and +lower of the natural groups of the Primates; +they stand between the oldest Placentalia +(Prochoriata) and the true Simiæ. (3) All +the Catarrhinæ, or Eastern Simiæ, form one +natural monophyletic group. Their hypothetical +common ancestor, the Archipithecus, +may have descended directly or indirectly +from a branch of the Lemures. (4) Man +is descended directly from one series of +extinct Catarrhine ancestors. The more +recent ancestors of this series were tailless +anthropoids (similar to the Anthropopithecus), +with five sacral vertebræ. The +more remote ancestors were tailed Cercopitheci, +with three or four sacral vertebræ.</p> + +<p>These four theses possess, in my opinion, +absolute certainty. They are independent of +all future anatomical, embryological, and +palæontological discoveries which may possibly +throw more light upon the details of +our phyletic anthropogenesis.</p> + +<p><span class="pagenum"><a name="Page_20" id="Page_20">[Pg 20]</a></span></p> + +<hr class="chap"/> +<div class="chapter-beginning"/> +<h2>II.</h2> + + +<p>The next question is, how the facts of +palæontology agree with these most important +results of comparative anatomy and ontogeny. +The fossils are the true historical 'medals of +creation,' the palpable evidence of the historical +succession of all those innumerable +organic forms which have peopled the globe +for many millions of years. Here the question +arises, If the known fossil specimens of Mammalia, +and particularly of Primates, give proof +of these Pithecometra-theses, do they confirm +directly the descent of man from ape-like +creatures? The answer to this question +is, in my opinion, affirmative.</p> + +<p>It is true that the gaps in the palæontological +evidence, here as elsewhere, are<span class="pagenum"><a name="Page_21" id="Page_21">[Pg 21]</a></span> +many and keenly felt. In the order of the +Primates they are greater than in many +other orders, chiefly because of the arboreal +life of our ancestors. The explanation is very +simple. It is really due to a long chain of +favourable coincidences if the skeleton of a +vertebrate, covered as it was with flesh and +skin, and containing still more perishable +viscera, is petrified at all. The body may be +devoured by other creatures, and its bones +scattered about; or it rots away and crumbles +to pieces. Many animals hide in thick undergrowth +when death approaches them; and, +leading an almost entirely arboreal life, the +Primates are especially likely to disappear +without being fossilized. It is only when the +body is quickly covered with sand, or is embedded +in suitable lime or silica containing +mud, that the process of petrifaction can +come to pass. Even then it is only by great +good luck that we come across such a fossil. +Very few countries have been searched +systematically, and the areas that have been<span class="pagenum"><a name="Page_22" id="Page_22">[Pg 22]</a></span> +searched amount to little in comparison with +the whole surface of the land, even if we +leave out of account the fact that more than +two-thirds of the globe are covered by water.</p> + +<p>These deplorable deficiencies of empirical +palæontology are balanced on the other side +by a growing number of positive facts, which +possess an inestimable value in human +phylogeny. The most interesting and most +important of these is the celebrated fossil +<i>Pithecanthropus erectus</i>, discovered in Java +in 1894 by Dr. Eugène Dubois.<a name="FNanchor_10_10" id="FNanchor_10_10"></a><a href="#Footnote_10_10" class="fnanchor">[10]</a> Three +years ago this now famous ape-like man +provoked an animated discussion at the third +International Zoological Congress at Leyden. +I may therefore be allowed to say a few +words as to its scientific significance. Unfortunately, +the fossil remains of this creature +are very scanty: the skull-cap, a femur, and +two teeth. It is obviously impossible to form<span class="pagenum"><a name="Page_23" id="Page_23">[Pg 23]</a></span> +from these scanty remains a complete and +satisfactory reconstruction of this remarkable +Pliocene Primate.</p> + +<p>The more important points are the following: +The remains in question rested upon a +conglomerate which lies upon a bed of marine +marl and sand of Pliocene age. Together +with the bones of Pithecanthropus were found +those of Stegodon, Leptobos, Rhinoceros, Sus, +Felis, Hyæna, Hippopotamus, Tapir, Elephas, +and a gigantic Pangolin. It is remarkable +that the first two of these genera are now +extinct, and that neither hippopotamus nor +hyæna exists any longer in the Oriental region. +If we may judge from these fossil remains, +the bones of Pithecanthropus are not younger +than the oldest Pleistocene, and probably +belong to the upper Pliocene. The teeth +are like those of man. The femur, also, is +very human, but shows some resemblances +to that of the gibbons. Its size, however, +indicates an animal which stood when erect +not less than 5 feet 6 inches high. The<span class="pagenum"><a name="Page_24" id="Page_24">[Pg 24]</a></span> +skull-cap also is very human, but with very +prominent eyebrow ridges, like those of +the famous Neanderthal cranium. It is +certainly not that of an idiot. It had an +estimated cranial capacity of about 1,000 +cubic centimetres—that is to say, much +more than that of the largest ape, which +possesses not more than 600 c.c. The crania +of female Australians and Veddahs measure +not more than 1,100, some even less than +1,000 c.c.; but, as these Veddah women stand +only about 4 feet 9 inches high, the computed +cranial capacity of the much taller Pithecanthropus +is comparatively very low indeed.<a name="FNanchor_11_11" id="FNanchor_11_11"></a><a href="#Footnote_11_11" class="fnanchor">[11]</a></p> + +<div class="figcenter"><a href="./images/i_0331.jpg"> + <img src="./images/i_0331.jpg" alt="Skulls"></img></a> +</div> + +<blockquote> +<p><small>The upper figure represents the outlines of the skull of Pithecanthropus, +as restored by Manouvier.<a name="FNanchor_12_12" id="FNanchor_12_12"></a><a href="#Footnote_12_12" class="fnanchor">[12]</a> The lower figure shows the +comparative size and shape of Pithecanthropus, the Neanderthal +skull, a specimen of the Cro-Magnon race of neolithic France, and a +Young Chimpanzee before the full development of the supraorbital +crests</small>.</p> +</blockquote> + +<p>The final result of the long discussion at +Leyden was that, of twelve experts present, +three held that the fossil remains belonged +to a low race of man; three declared them +to be those of a man-like ape of great size;<span class="pagenum"><a name="Page_25" id="Page_25">[Pg 25]</a><br /><a name="Page_26" id="Page_26">[Pg 26]</a></span> +the rest maintained that they belonged to an +intermediate form, which directly connected +primitive man with the anthropoid apes. +This last view is the right one, and accords +with the laws of logical inference. <i>Pithecanthropus +erectus</i> of Dubois is truly a +Pliocene remainder of that famous group of +highest Catarrhines which were the immediate +pithecoid ancestors of man. He is, indeed, the +long-searched-for 'missing link,' for which, in +1866, I myself had proposed the hypothetical +genus Pithecanthropus, species Alalus.</p> + +<p>It must, however, be admitted that this +opinion is still strongly combated by some +distinguished authorities. At the Leyden +Congress it was attacked by the illustrious +pathologist Rudolf Virchow.<a name="FNanchor_13_13" id="FNanchor_13_13"></a><a href="#Footnote_13_13" class="fnanchor">[13]</a> He, however, +is one of the minority of leading men of +science who set themselves to refute the +theory of Evolution in every possible way. +For thirty years he has defended the thesis: +'It is quite certain that man is not a<span class="pagenum"><a name="Page_27" id="Page_27">[Pg 27]</a></span> +descendant of apes.' He declares any intermediate +form to be unimaginable save in a +dream.</p> + +<p>Virchow went to the Leyden Congress +with the set purpose of disproving that the +bones found by Dubois belonged to a creature +which linked together apes and man. First, +he maintained that the skull was that of an +ape, while the thigh belonged to man. This +insinuation was at once refuted by the expert +palæontologists, who declared that without +the slightest doubt the bones belonged to +one and the same individual. Next, Virchow +explained that certain exostoses or growths +observable on the thigh proved its human +nature, since only under careful treatment +the patient could have healed the original +injury. Thereupon Professor Marsh, the +celebrated palæontologist, exhibited a number +of thigh-bones of wild monkeys which +showed similar exostoses and had healed +without hospital treatment. As a last argument +the Berlin pathologist declared that<span class="pagenum"><a name="Page_28" id="Page_28">[Pg 28]</a></span> +the deep constriction behind the upper +margin of the orbits proved that the skull +was that of an ape, as such never occurred in +man. It so happened that a few weeks later +Professor Nehring of Berlin demonstrated +exactly the same formation on a human prehistoric +skull received by him from Santos, +in Brazil.</p> + +<p>Virchow was, in fact, just as unlucky in +Leyden in his fight with our pliocene +ancestor as he had been unfortunate in his +opinion on the famous skulls of Neanderthal, +Spy, La Naulette, etc., every one of which he +explained as a pathological abnormality. It +would be a very curious coincidence indeed if +all these and other fossil human remains +were those of idiots or otherwise abnormal +individuals, provided they are old and low +enough in their organization to be of phylogenetic +value to the unbiassed zoologist.</p> + +<p>As the sworn adversary of Evolution, +transformism, and Darwinism in particular, +but a believer in the constancy of species, the<span class="pagenum"><a name="Page_29" id="Page_29">[Pg 29]</a></span> +great and renowned pathologist has been +driven to the incredible contention that all +variations of organic forms are pathological.</p> + +<p>Four years ago, as honorary president of +the Anthropological Congress at Vienna, he +attacked Darwinism in the severest manner, +and declared that 'man may be as well +descended from the elephant or from the +sheep as from the ape.' Such attacks on the +theory of transformism indicate a failure to +understand the principles of the theory of +Evolution and to appreciate the significance +of palæontology, comparative anatomy, and +ontogeny.</p> + +<p>The thousands of other objections which +have been made during the last forty years +(chiefly by outsiders) may be passed over in +silence. They do not require serious refutation. +In spite of, or perhaps because of, +these attacks, the theory of Evolution stands +established more firmly than ever.</p> + +<p>It is easy for the outsider to exult over the +difficulties which our problem implies—diffi<span class="pagenum"><a name="Page_30" id="Page_30">[Pg 30]</a></span>culties +which we who have given our lives to +the study understand likewise, and try our +best not only to bridge over, but also to +point out. Anyhow, we do not conceal +them; while those who reject the explanation +offered by Evolution make the most of the +gaps, and pass silently over the far more +numerous points favourable to our theory.</p> + +<p>How fruitful during the last thirty years +the astonishing progress in our palæontological +knowledge has been for our Pithecometra-thesis +is best shown by a short glance +at the growth of our knowledge of fossil +Primates. Cuvier,<a name="FNanchor_14_14" id="FNanchor_14_14"></a><a href="#Footnote_14_14" class="fnanchor">[14]</a> the founder of palæontology, +continued up to the time of his death, +in 1832, to assert that fossil remains of +monkeys and lemurs did not exist. The +only skull of a fossil lemuroid which he described +(namely, Adapis) he declared to be +that of an ungulate. Not until 1836 were +the first fragments of extinct monkeys found +in India; it was two years later, near Athens,<span class="pagenum"><a name="Page_31" id="Page_31">[Pg 31]</a></span> +that the skeleton of <i>Mesopithecus penthelicus</i> +was discovered. Other remains of lemurs +were found in 1862. But during the last +twenty years the number of fossil Primates +has been augmented by the remarkable discoveries +of Gaudry, Filhol, Milne Edwards, +Seeley, Schlosser, and others in Europe; of +Marsh, Cope, Osborn, Leidy, Ameghino, in +South America; and Forsyth Major in +Madagascar.<a name="FNanchor_15_15" id="FNanchor_15_15"></a><a href="#Footnote_15_15" class="fnanchor">[15]</a> These tertiary remains, chiefly<span class="pagenum"><a name="Page_32" id="Page_32">[Pg 32]</a></span> +of Eocene and Miocene date, fill many gaps +between existing genera of Primates, and +afford us quite a clear insight into the phyletic +development of this order during the +millions of years of the Cænozoic age.</p> + +<p>The most important difference between the +two groups of existing monkeys is indicated +by their dentition. Adult man possesses, +like all the other Catarrhine Simiæ, thirty-two +teeth, whilst the American monkeys (the +Platyrrhinæ) have thirty-six teeth—namely, +one pair of premolars more in the upper and +lower jaws. Comparative odontology leads +us to the phylogenetic conclusion that this +number has been produced by reduction from +a still older form with forty-four teeth. This +typical dental formula (three incisors, one +canine, four premolars, and three molars, in +each half-jaw) is common to all those most +important older mammals which in the beginning +of the Eocene period constituted the four +large groups of Lemuravida, Condylarthra, +Esthonychida, and Ictopsida. These are the<span class="pagenum"><a name="Page_33" id="Page_33">[Pg 33]</a></span> +four ancestral groups of the four main orders +of Placentalia—namely, of the Primates, +Ungulata, Rodentia, and Carnassia. They +seem to be so closely related by their primitive +organization that they may be united in +one common super-order, Prochoriata.</p> + +<p>With a considerable degree of probability, +we are led to formulate the further +hypothesis that all the orders of Placentalia—from +the lowest Prochoriata upwards to +man—have descended from some unknown +common ancestor living in the Cretaceous +period, and that this oldest placental form +originated from some Jurassic group of +marsupials.</p> + +<p>Among these numerous fossil Lemures +which have been discovered within the last +twenty years, there exist, indeed, all the connecting +forms of the older series of Primates, +all the 'missing links' sought for by comparative +odontology.</p> + +<p>The oldest Lemures of the tertiary age +are the Eocene Pachylemures, or Hyopso<span class="pagenum"><a name="Page_34" id="Page_34">[Pg 34]</a></span>dina. +They possess the complete dentition +of the Prochoriata—namely, forty-four teeth +(3.1.4.3/3.1.4.3). Then follow the Eocene Palæolemures, +or Adapida, with forty teeth, they +having lost one pair of incisors in each jaw. +To these are attached the younger Autolemures, +or Stenopida, with thirty-six teeth, +they thus possessing already the same dentition +as the Platyrrhinæ. The characteristic +dentition of the Catarrhinæ is derived from +this formula by the loss of another premolar.</p> + +<p>These relations are so clear and so closely +connected with a gradual transformation of +the whole skull, and with the progressive +differentiation of the Primate-form, that we +are justified in saying that the pedigree of the +Primates, from the oldest Eocene Lemures +upwards to man, is now so well known, its +principal features so firmly fixed within the +Tertiary age, that there is no missing link +whatever.</p> + +<p>Quite different, and much more incom<span class="pagenum"><a name="Page_35" id="Page_35">[Pg 35]</a></span>plete, +is the palæontological evidence, if we +go further back into the Secondary or Mesozoic +age, and look there for the older ancestors +of the mammalian series. There we +meet everywhere with wide gaps, and the +scarce fragments of fossil Mesozoic mammals +(excessively rare in the Cretaceous formation) +are too poor to permit definite conclusions as +to their systematic position. Indeed, comparative +anatomy and ontogeny lead us to the +hypothesis that the oldest Cretaceous Mammalia—the +Prochoriata—are descended from +Jurassic marsupials, and these again from +Monotremes. We may also suppose with +high probability that among the unknown +Cretaceous Prochoriata there have been +Lemuravida and forms intermediate between +these and the Jurassic Amphitheriidæ, and +that these marsupials in their turn are descendants +of Pantotheria or similar monotreme-like +creatures of the Triassic age. Any +certain evidence for these hypotheses is at +present still wanting. One important fact,<span class="pagenum"><a name="Page_36" id="Page_36">[Pg 36]</a></span> +however, is established—namely, that these +interesting and oldest Mammalia—the Pantotheria +of Marsh, the Triassic Dromatheriidæ, +and the Jurassic Triconodontidæ of Osborn—were +small insectivorous mammals with a very +primitive organization. Probably they were +Monotremes, and may be derived directly +from Permian Sauromammalia, an ill-defined +mixture of Mammalia and Reptilia.</p> + +<p>This generalized characteristic supports +our view that <i>the whole class of Mammalia is +monophyletic</i>, and that all its members, from +the oldest Monotremes upwards to man, have +descended from one common ancestor living +in the older Triassic, or perhaps in the +Permian, age. To acquire full conviction of +this important conception, we have only to +think of the hair and the glands of our +human skin, of our diaphragm, the heart and +the blood corpuscles without a nucleus, our +skull with its squamoso-mandibular articulation. +All these singular and striking modifications +of the vertebrate organization are<span class="pagenum"><a name="Page_37" id="Page_37">[Pg 37]</a></span> +common to mammals, and distinguish them +clearly from the other Craniota. This characteristic +combination and correlation proves +that they have been developed only <i>once</i> in +the history of the vertebrate stem, and that +they have been transferred by heredity from +one common ancestor to all the members of +the class of Mammalia.</p> + +<p>The next step, as we trace our human +phylogeny to its origin, leads us further back +into the lower Vertebrata, into that obscure +Palæozoic age the immeasurable length of +which (much greater than that of the +Mesozoic) may, according to one of the +newest geological calculations, have comprised +about one thousand millions of years.<a name="FNanchor_16_16" id="FNanchor_16_16"></a><a href="#Footnote_16_16" class="fnanchor">[16]</a></p> + +<p>The first important fact we have to face +here is the complete absence of mammalian +remains. Instead of these we find in the +later Palæozoic period, the Permian, air-breathing +<i>reptiles</i> as the earliest representatives +of Amniota. They belong to the<span class="pagenum"><a name="Page_38" id="Page_38">[Pg 38]</a></span> +most primitive order of that class, the +Tocosauria; and besides them there were +the Theromorpha, which approach the Mammalia +in a remarkable manner. These +reptiles in turn were preceded, in the Carboniferous +period, by true Amphibia, most +of them belonging to the armour-clad +Stegocephali. These interesting Progonamphibia +were the oldest Tetrapoda, the first +vertebrates which had adapted themselves +to the terrestrial mode of life; in them the +swimming fin of fishes and Dipneusta was +transformed into the pentadactyle extremities +characteristic of quadrupeds.</p> + +<p>To appreciate the high importance of this +metamorphosis, we need only compare the +skeleton of our own human limbs with that +of the living Amphibia. We find in the +latter the same characteristic composition +as in man: the same shoulder and pelvic +girdle; the same single bone, the humerus +or the femur, followed by the same pair of +bones in the forearm and leg; then the same<span class="pagenum"><a name="Page_39" id="Page_39">[Pg 39]</a></span> +skeletal elements composing the wrist and +the ankle regions; and, lastly, the same five +fingers and toes.</p> + +<p>The arrangement of these bones, peculiar +and often complicated, but everywhere +essentially the same in all the Tetrapoda, +is a striking evidence that man is a +descendant from the oldest pentadactyle +Amphibia of the Carboniferous period. In +man the pentadactyle type has been better +preserved by constant heredity than in many +other Mammalia, notably the Ungulata.</p> + +<p>The oldest Carboniferous Amphibia, the +armour-clad Stegocephali, and especially the +remarkable Branchiosauri discovered by +Credner, are now regarded by all competent +zoologists as the indubitable common ancestral +group of all Tetrapoda, comprising both +Amphibia and Amniota. But whence this +most remote group of Tetrapoda? That +difficult question is answered by the marvellous +progress of modern palæontology, and +the answer is in complete harmony with<span class="pagenum"><a name="Page_40" id="Page_40">[Pg 40]</a></span> +the older results arrived at by comparative +anatomy and ontogeny. Thirty-four years +ago Carl Gegenbaur,<a name="FNanchor_17_17" id="FNanchor_17_17"></a><a href="#Footnote_17_17" class="fnanchor">[17]</a> the great living master +of comparative anatomy, had demonstrated +in a series of works how the skeletal +parts of the various classes of Vertebrata, +especially the skull and the limbs, still represent +a continuous scale of phyletic gradations. +Apart from the Cyclostomes, there are the +fishes, and among them the Elasmobranchi +(sharks and rays), which have best preserved +the original structure in all its essential parts +of organization. Closely connected with the +Elasmobranchi are the Crossopterygii, and +with these the Dipneusta or Dipnoi. Among +the latter the highest importance attaches +to the ancient Australian Ceratodus. Its +organization and development is now, at +last, becoming well known. This transitional +group of Dipnoi, 'fishes with lungs' +but without pentadactyle limbs, is the +morphological bridge which joins the<span class="pagenum"><a name="Page_41" id="Page_41">[Pg 41]</a></span> +Ganoids and the oldest Amphibia. With +this chain of successive groups of Vertebrata, +constructed anatomically, the palæontological +facts agree most satisfactorily. +Selachians and Ganoids existed in the +Silurian times, Dipnoi in the Devonian, +Amphibia in the Carboniferous, Reptilia in +the Permian, Mammalia in the Trias. These +are historical facts of first rank. They +connote in the most convincing manner that +remarkable ascending scale in the series of +vertebrates for our knowledge of which we +are indebted to the works of Cuvier and +Blainville, Meckel, Johannes Mueller and +Gegenbaur, Owen and Huxley. The historical +succession of the classes and orders +of the Vertebrata in the course of untold +millions of years is definitely fixed by the +concordance of those leading works, and this +invaluable acquisition is much more important +for the foundation of our human +pedigree than would be a complete series of +all possible skeletons of Primates.</p> + +<p><span class="pagenum"><a name="Page_42" id="Page_42">[Pg 42]</a></span></p> + +<p>Greater and more frequent difficulties +arise if we penetrate further into the most +remote part of the human phylogeny, and +attempt to derive the vertebrate stem from +an older stem of invertebrate ancestors. +None of those had a skeleton which could be +petrified; and the same remark applies to +the lowest classes of Vertebrata—to the +Cyclostomes and the Acrania. Palæontology, +therefore, can tell us nothing about them; +and we are limited to the other two great +documents of phylogeny—the results of comparative +anatomy and ontogeny. The value +of their evidence is, however, so great that +every competent zoologist can perceive the +most important features of the most remote +portion of our phylogeny.</p> + +<p>Here the first place belongs to the invaluable +results which modern comparative +ontogeny has gained by the aid of the +biogenetic law or the theory of recapitulation. +The foundation-stones of vertebrate embryology +had been laid by the works of Von<span class="pagenum"><a name="Page_43" id="Page_43">[Pg 43]</a></span> +Baer, Bischoff,<a name="FNanchor_18_18" id="FNanchor_18_18"></a><a href="#Footnote_18_18" class="fnanchor">[18]</a> Remak, and Koelliker;<a name="FNanchor_19_19" id="FNanchor_19_19"></a><a href="#Footnote_19_19" class="fnanchor">[19]</a> but +the clearest light was thrown upon it by the +famous discoveries of Kowalevsky<a name="FNanchor_20_20" id="FNanchor_20_20"></a><a href="#Footnote_20_20" class="fnanchor">[20]</a> in 1866. +He proved the identity of the first developmental +stages of Amphioxus and +the Ascidians, and thereby confirmed the +divination of Goodsir, who had already +announced the close affinity of Vertebrates +and Tunicates. The acknowledgment of +this affinity has proved of increasing importance, +and has abolished the erroneous +hypothesis that the Vertebrata may have +arisen from Annelids or from other Articulata. +Meanwhile, from 1860 to 1872, I +myself had been studying the development +of the Spongiæ, Medusæ, Siphonophora, and +other Cœlenterata. Their comparison led +me to the statements embodied in the<span class="pagenum"><a name="Page_44" id="Page_44">[Pg 44]</a></span> +'Gastræatheorie,' the first abstract of which +was published in 1872 in my monograph of +the Calcispongiæ.</p> + +<p>These ideas were carried on and expanded +during the subsequent ten years by +the help of many excellent embryologists—first +of all by E. Ray Lankester and Francis +Balfour. The most fruitful result of these +widely extended researches was the conclusion +that the first stages of embryonic +development are essentially the same in all +the different Metazoa, and that we may +derive from these facts certain views on the +common descent of all from one ancestral +form. The unicellular egg<a name="FNanchor_21_21" id="FNanchor_21_21"></a><a href="#Footnote_21_21" class="fnanchor">[21]</a> repeats the stage +of our Protozoan ancestors; the Blastula is +equivalent to an ancestral cœnobium of +Magosphæra or Volvox; the Gastrula is +the hereditary repetition of the Gastræa, the +common ancestor of all the Metazoa.</p> + +<p>Man agrees in all these respects with the +other vertebrates, and must have descended +with them from the same common root.</p> + +<p><span class="pagenum"><a name="Page_45" id="Page_45">[Pg 45]</a></span></p> + +<p>Particularly obscure is that part of our +phylogeny which extends from the Gastræa +to Amphioxus. The morphological importance +of this last small creature had been +perceived by Johannes Mueller, who in 1842 +gave the first accurate description of it. It +would not, of course, be correct to proclaim +the modern Amphioxus the common ancestor +of all the vertebrates; but he must be regarded +as closely related to them, and as the only +survivor of the whole class of Acrania. If +the Amphioxidæ had through some unfortunate +accident become extinct, we should +not have been able to gain anything like a +positive glimpse at our most remote vertebrate +ancestor. On the one hand, Amphioxus is +closely connected with the early larva of the +Cyclostomes, which are the oldest Craniota, +and the pre-Silurian ancestors of the fishes. +On the other hand, the ontogeny of Amphioxus +is in harmony with that of the Ascidians, +and if this agreement is not merely coincidental, +but due to relationship, we are +justified in reconstructing for both Ascidians<span class="pagenum"><a name="Page_46" id="Page_46">[Pg 46]</a></span> +and Amphioxus one common ancestral group +of chordate animals, the hypothetical <i>Prochordonia</i>. +The modern Copelata give us +a remote idea of their structure. The curious +Balanoglossus, the only living form of Enteropneusta, +seems to connect these Prochordonia +with the Nemertina and other Vermalia, +which we unite in one large class—Frontonia.</p> + +<p>No doubt these pre-Cambrian Vermalia, +and the common root of all Metazoa, the +Gastræades, were connected during the +Laurentian period by a long chain of intermediate +forms, and probably among these +were some older forms of Rotatoria and +Turbellaria; but at present it is not possible +to fill this wide gap with hypotheses that +are satisfactory, and we have to admit that +here indeed are many missing links in the +older history of the Invertebrata. Still, +every zoologist who is convinced of the truth +of transformism, and is accustomed to phylogenetic +speculations, knows very well that +their results are most unequal, often incomplete.</p> + +<p><span class="pagenum"><a name="Page_47" id="Page_47">[Pg 47]</a></span></p> + +<hr class="chap"/> +<div class="chapter-beginning"/> +<h2>III.</h2> + + +<p>Let us now recapitulate the ancestral chain +of man, as it is set forth in the accompanying +diagram (p. <a name="FNanchor_55_55" id="FNanchor_55_55"></a><a href="#Footnote_55_55" class="label">55</a>), which represents our present +knowledge of our descent. For simplicity's +sake the many side-issues or branches which +lead to groups not in the main line of our +descent have been left out, or have been indicated +merely. Many of the stages are of +course hypothetical, arrived at by the study +of comparative anatomy and ontogeny; but +an example for each of them has been taken +from those living or fossil creatures which +seem to be their nearest representatives.</p> + +<p>1. The most remote ancestors of all living +organisms were living beings of the simplest +imaginable kind, organisms without organs,<span class="pagenum"><a name="Page_48" id="Page_48">[Pg 48]</a></span> +like the still existing <i>Monera</i>. Each consisted +of a simple granule of protoplasm, a +structureless mass of albuminous matter or +plasson, like the recent Chromaceæ and +Bacteriæ. The morphological value of these +beings is not yet that of a cell, but that of a +cytode, or cell without a nucleus. Cytoplasm +and nucleus were still undifferentiated.</p> + +<p>I assume that the first Monera owe their +existence to spontaneous creation out of so-called +anorganic combinations, consisting of +carbon, hydrogen, oxygen, and nitrogen. An +explanation of this hypothesis I have given +in my 'Generelle Morphologie.'</p> + +<p>The Monera probably arose early in the +Laurentian period. The oldest are the +Phytomonera, with vegetable metabolism. +They possessed the power (characteristic of +plants) of forming albumin by synthesis from +carbon, water, and ammonia. From some of +these plasma-forming Monera arose the +plasmophagous Zoomonera with animal metabolism, +living directly upon the produce of<span class="pagenum"><a name="Page_49" id="Page_49">[Pg 49]</a></span> +their plasmodomous or plasma-forming +sisters. This is the first instance of the +great principle of division of labour.</p> + +<p>2. The second stage is that of the <i>simple +and single cell</i>, a bit of protoplasm with a +nucleus. Such unicellular organisms are +still very common. The <i>Amœbæ</i> are their +simplest representatives. The morphological +value of such beings is the same as that of +the egg of any animal. The naked egg cells +of the sponges creep about in an amœboid +fashion, scarcely distinguishable from Amœba. +The same remark applies to the egg-cell of +man himself in its early stages before it is +enclosed in a membrane. The first unicellular +organisms arose from Monera through differentiation +of the inner nucleus from the outer +protoplasm.</p> + +<p>3. Repeated division of the unicellular +organism produces the <i>Synamœbium</i>, or +community of Amœbæ, provided the divisional +products, or new generations of the +original cell, do not scatter, but remain<span class="pagenum"><a name="Page_50" id="Page_50">[Pg 50]</a></span> +together. The existence of such a <i>Cœnobium</i>, +a number of equal and only loosely-connected +cells, as a separate stage in the ancestral +history of animals, is made highly probable by +the fact that the eggs of all animals undergo +after fertilization such a process of repeated +self-division, or 'cleavage,' until the single +egg cell is transformed into a heap of cells +closely packed together, not unlike a mulberry +(<i>morula</i>)—hence <i>morula</i> stage in ontogeny.</p> + +<p>4. The morula of most animals further +changes into a <i>Blastula</i>, a hollow ball filled +with fluid, the wall being formed by a single +layer of cells, the blastoderm or germinal layer. +This modification is brought about by the +action of the cells—they conveying nourishing +fluid into the interior of the whole cell +colony and thereby being themselves forced +towards the surface. The Blastula of most +Invertebrata, and even that of Amphioxus, is +possessed of fine ciliæ, or hair-like processes, +the vibrating motion of which causes the +whole organism to rotate and advance in<span class="pagenum"><a name="Page_51" id="Page_51">[Pg 51]</a></span> +the water. Living representatives of such +Blastæads, namely, globular gelatinous +colonies of cells enclosing a cavity, are +Volvox and Magosphæra.</p> + +<p>5. The Blastula of most animals assumes +a new larval form called <i>Gastrula</i>, in which +the essential characteristics are that a portion +of the blastoderm by invagination converts +the Blastula into a cup with double walls, +enclosing a new cavity, the primitive gut. +This invagination or bulging-in obliterates +the original inner cavity of the Blastula. +The outer layer of the Gastrula is the ectoderm, +the inner the endoderm; both pass +into each other at the blastoporus, or opening +of the gut cavity. The Gastrula is a stage +in the embryonic development of the various +great groups of animals, and some such +primitive form as ancestral to all Metazoa is +thus indicated. This hypothetical <i>Gastræa</i> +is still very essentially represented by the +lower Cœlenterates—<i>e.g.</i>, Olynthus, Hydra.</p> + +<p>6. The sixth stage—that of the <i>Platodes</i>,<span class="pagenum"><a name="Page_52" id="Page_52">[Pg 52]</a></span> +or flat-worms—is very hypothetical. They +are bilateral gastræads, with a flattened +oblong body, furnished with ciliæ, with a +primitive nervous system, simple sensory and +reproductive organs, but still without appendages, +body cavity, vent, and blood-vessels. +The nearest living representatives of such +creatures are the acœlous Turbellarians—<i>e.g.</i>, +Convoluta, a free-swimming, ciliated creature.</p> + +<p>7. The next higher stage is represented +by such low animals as the <i>Gastrotricha</i>—<i>e.g.</i>, +Chætonotus among the Rotatoria, which +differ from the rhabdocœlous Turbellarians +chiefly by the formation of a vent and the +beginnings of a cœlom, or cavity, between +gut and body wall. The addition of a primitive +vascular system and a pair of nephridia, +or excretory organs, is first met with in the +<i>Nemertines</i>.</p> + +<p>8. These, together with the <i>Enteropneusta</i> +(Balanoglossus), are comprised under the +name of Frontonia, or Rhynchelminthes, +and form the highest group of the Vermalia.</p> + +<p><span class="pagenum"><a name="Page_53" id="Page_53">[Pg 53]</a></span></p> + +<p>The Enteropneusta especially fix our attention, +because they alone, although essentially +'worms,' exhibit certain characteristics which +make it possible to bridge over the gulf +which still separates the Invertebrata from +the vertebrate phylum. The anterior portion +of the gut is transformed into a breathing +apparatus—hence Gegenbaur's term of Enteropneusta, +or Gut-breathers. Moreover, +Balanoglossus and Cephalodiscus possess +another modification of the gut—namely, a +peculiar diverticulum, which, in the present +state of our knowledge, may be looked upon +as the forerunner of the chorda dorsalis.</p> + +<p>9. Stage of <i>Prochordonia</i>, as indicated by +the larval form, called Chordula, which is +common to the Tunicata and all the Vertebrata. +These two groups possess three most +important features: (<i>a</i>) A chorda dorsalis, +a stiff rod lying in the long axis of the +body, dorsally from the gut and below the +central nervous system. This latter, for the +first time in the animal kingdom, appears in<span class="pagenum"><a name="Page_54" id="Page_54">[Pg 54]</a></span> +the shape of a spinal cord. (<i>b</i>) The use of +the anterior portion of the gut for respiratory +purposes. (<i>c</i>) The larval development of +the Tunicata is essentially the same as that of +the Vertebrata in its early stages. Only the +free-swimming Copelata or Appendicularia +among the Tunicates retain most of these +features. The others, which become sessile—namely, +the Ascidiæ, or sea-squirts—degenerate +and specialize away from the +main line.</p> + +<p class="center"> +<a name="Footnote_55_55" id="Footnote_55_55"></a><a href="#FNanchor_55_55"><span class="label">ANCESTRAL TREE OF THE VERTEBRATA</span></a><br /> +<i>Abridged from 'Systemat. Phylogenie,' § 15.</i><br /> +Names underlined refer to hypothetical groups.</p> + +<table id="atv" summary="vertebrata"> + +<tr> + <td class="tdc"><i>Aves</i></td> + <td class="tdc"> </td> + <td class="tdc"><i>Mammalia</i></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc"><i>Reptilia</i></td> + <td class="tdc">|</td> +</tr> +<tr> + <td class="tdr">'———</td> + <td class="tdl">———|</td> + <td class="tdc">|</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdr">|———</td> + <td class="tdl">———'</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdc">|</td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdc"><i>Proreptilia</i></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdc"><i>Pisces</i></td> + <td class="tdc">|</td> + <td class="tdc"><i>Amphibia</i></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdr">|———</td> + <td class="tdl">———'</td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc"><i>Stegocephali</i></td> + <td class="tdc"><i>Dipnoi</i></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdr">|———</td> + <td class="tdl">———'</td> +</tr> +<tr> + <td class="tdr">'———</td> + <td class="tdl">———|</td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdc"><i>Proselachii</i></td> + <td class="tdc"><i> Cyclostomata</i></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdc">|</td> + <td class="tdc">|</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdr">|———</td> + <td class="tdl">———'</td> +</tr> +<tr> + <td class="tdl"> </td> + <td class="tdc">|</td> + <td class="tdr"> </td> +</tr> +<tr> + <td class="tdc"> <i>Tunicata</i> </td> + <td class="tdc"> <span class="u"><i>Archicrania</i></span></td> + <td class="tdc"><i>Acrania</i></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdr">|———</td> + <td class="tdl">———'</td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc"><span class="u"><i>Prospondylia</i></span></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdr">'———</td> + <td class="tdl">———|</td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdc"><span class="u"><i>Prochordonia</i> </span></td> + <td class="tdr"></td> +</tr> +</table> + +<p>10. Stage of the <i>Acrania</i>, represented by +Amphioxus. The early development of this +little marine creature agrees closely with that +of the Tunicates; but one important feature +is added to its organization—namely, metamerism, +segmentally arranged mesoderm. +Amphioxus still possesses neither skull nor +vertebræ, neither ribs nor jaws, and no limbs. +But it is a member of the Vertebrata if we +define these as follows: Bilateral symmetrical +animals with segmentally arranged mesoderm, +with a chorda dorsalis between the +<span class="pagenum"><a name="Page_55" id="Page_55">[Pg 55]</a></span> +<span class="pagenum"><a name="Page_56" id="Page_56">[Pg 56]</a></span> +tubular nervous system and the gut, and with +respiratory organs which arise from the anterior +portion of the gut. We do not assume +that Amphioxus stands in the direct ancestral +line; it is probably much specialized, partly +degenerated, and represents a side-branch; +but it is, nevertheless, the only creature, +hitherto known, which satisfactorily connects +the Vertebrata with their invertebrate ancestors. +Many other efforts have been made to +solve the mystery of the origin of the Vertebrata—all +less satisfactory than the present +suggestion, or even absolutely futile. This +remark applies especially to the attempts +to derive them from either Articulata or +Echinoderms. The other great and highly +developed phylum, the Mollusca, is quite +out of the question. We have to go back to +a level at which all these principal phyla +meet, and there we find the Vermalia, the +lower of which alone permit connection in an +upward direction with the higher phyla.</p> + +<p>11. Stage of <i>Cyclostomata</i>. This now<span class="pagenum"><a name="Page_57" id="Page_57">[Pg 57]</a></span> +small group of Lampreys and Hagfishes +represents the lowest Craniota; and although +much specialized as a side-branch of the +main-stem from which the other Craniota +have sprung, they give us an idea of what +the direct ancestors of the latter must have +been like:—still without visceral arches, +without jaws and without paired limbs; with +a persistent pronephros; the ear with one +semicircular canal only; mouth suctorial; +cranium very primitive; and the metamerism +of the vertebral column indicated only by +little blocks of cartilage in the perichordal +sheath. Such creatures must have existed +at least as early as the Lower Silurian +epoch; but until 1890 fossil Cyclostomes were +unknown. Their life in the mud, or as +endoparasites of fishes, coupled with their +soft structure, makes them very unfit for +preservation. This gives all the greater importance +to Traquair's discovery, in 1890, of +many little creatures, called by him <i>Palæospondylus +gunni</i>, in the Old Red Sandstone of<span class="pagenum"><a name="Page_58" id="Page_58">[Pg 58]</a></span> +Caithness, which seem to be very closely +allied to Cyclostomata.</p> + +<p>12. The <i>Elasmobranchi</i> (sharks and skates), +with their immediate forerunners, the Acanthodi +of the Devonian and Carboniferous age, +are the first typical fishes. That they existed +as far back as the Silurian age is proved by +many enamelled spines of the dermal armour, +chiefly from the dorsal fins. This higher +stage is characterized by the possession of +typical jaws, by visceral or gill-bearing arches, +and by two pairs of limbs. None of the +Elasmobranchs, fossil or recent, stands in the +direct ancestral line; but they are the lowest +Gnathostomata, jaw-and-limb-possessing +creatures, known.</p> + +<p>13. Closely connected with the Elasmobranchs +in a wider sense are the <i>Crossopterygii</i>, +which begin in the Devonian age as a +large group, but have left only two survivals, +the African Polypterus and Calamoichthys. +They are possessed of dermal bones and +other ossifications, and are characterized by<span class="pagenum"><a name="Page_59" id="Page_59">[Pg 59]</a></span> +their lobate paired fins, which have a thick +axis beset with biserial fin rays. Their gill-clefts +are covered by an operculum, and they +have a well-developed air-bladder. Whilst +they are in many respects more highly +developed than the Elasmobranchs, and are +intimately connected with the typical Ganoids +and other bony fishes (all of which form a +great, manifold side-branch of the general +vertebrate stem), they stand in many other +respects (notably, the structure of the paired +fins, the vertebral column, and the air-bladder) +nearer the main-stem of our own +ancestral line.</p> + +<p>14. This is shown by their intimate +relation to the <i>Dipnoi</i>, which are still represented +by the Australian, African, and South +American mud-fishes: Ceratodus, Protopterus, +and Lepidosiren. The genus Ceratodus +existed in the Upper Trias, whence various +other unmistakably dipnoous forms lead down +through the Carboniferous (<i>e.g.</i>, Ctenodus) +to the Devonian strata—<i>e.g.</i>, Dipterus. They<span class="pagenum"><a name="Page_60" id="Page_60">[Pg 60]</a></span> +are characterized as follows: The paired fins +still retain the archipterygial form (namely, +one axis with biserial rays); the heart is +already trilocular, and receives blood which +is mixed arterial and venous, owing to the +gills being retained, while the air-bladder has +been modified into a lung. In fact, the +generalized Dipnoi form the actual link between +fishes and <i>Amphibia</i>.</p> + +<p>15. <i>Amphibia.</i> The earliest amphibian +fossils occur in the Carboniferous strata. +They alone—the Stegocephali or Phractamphibia—stand +in the ancestral line, while the +Lissamphibia, to which all the recent forms +belong, are side-branches. The Stegocephali +are the earliest Tetrapoda, the archipterygial +paired fins having been transformed into +the pentadactyle fore and hind limbs, which +are so characteristic of all the higher Vertebrata. +The cranium is roofed over by dermal +bones, of which, besides others, supra-occipitals, +supra-orbitals, and supra-temporals +are always present. The lowest members<span class="pagenum"><a name="Page_61" id="Page_61">[Pg 61]</a></span> +(Branchiosauri) still retained gills besides +the lungs, while others (Microsauri) have +lost the gills. Be it remembered that all the +recent Amphibia still undergo the same metamorphosis +during their ontogenetic development.</p> + +<p>In the very important Temnospondyli, a +subgroup of the Stegocephali—<i>e.g.</i>, Trimerorhachis +of the Lower Red Sandstone or Lower +Permian—the component cartilaginous or +bony units which compose the vertebræ still +remained in a separate, unfused state, showing +at the same time an arrangement whence +has arisen that which is typical of the Amniota. +The same applies to the limbs and +their girdles. In fact, the Stegocephali, taken +as a whole, lead imperceptibly to the <i>Proreptilia</i>.</p> + +<p>16. <i>Proreptilia</i> are represented by the +Permian genera Eryops and Cricotus. Until +quite recently these and many other fossils +from the Carboniferous strata were looked +upon as Amphibia, while many undoubted<span class="pagenum"><a name="Page_62" id="Page_62">[Pg 62]</a></span> +fossil Amphibia were mistaken for reptiles, +as indicated by the frequent termination +'-saurus' in their names.</p> + +<p>The nearest living representative of these +extinct Proreptilia is the New Zealand +reptile Hatteria, or Sphenodon, close relations +of which are known from the Upper Trias; +while others—<i>e.g.</i>, Palæohatteria—have been +discovered in the Permian. Anyhow, Sphenodon +is the reptile which stands nearest to the +main stem of our ancestry.</p> + +<p>The most important characteristics of the +Reptilia, which mark a higher stage or level, +are (1) The entire suppression of the gills—although +during the embryonic development +the gill-clefts still appear in all reptiles, birds, +and mammals; (2) The development of an +amnion and an allantois, both for the embryonic +life only, but so characteristic that all +these animals are comprised under the name +of Amniota; (3) The articulation of the skull +with the first neck vertebræ by well-developed +condyles, either single (really triple) or<span class="pagenum"><a name="Page_63" id="Page_63">[Pg 63]</a></span> +double (such a condylar arrangement begins +with the Amphibia, but only the two lateral +condyles are developed, while the middle +portion, belonging to the basi-occipital element, +remains rudimentary<a name="FNanchor_22_22" id="FNanchor_22_22"></a><a href="#Footnote_22_22" class="fnanchor">[22]</a>); (4) The formation +of centra, or bodies of the vertebræ, +mainly by a ventral pair of the original quadruple +constituents, or arcualia.</p> + +<p>17. Between the Proreptilia and the Mammalia, +which latter occur in the Upper Triassic +epoch, we have necessarily to intercalate a +group of very low reptiles, which are still so +generalized that their descendants could +branch off either into the Reptilia proper or +into the Mammalia. The changes concerned +chiefly the brain and the heart; of the skele<span class="pagenum"><a name="Page_64" id="Page_64">[Pg 64]</a></span>ton, +the skull and the pelvis; and, of the +tegumentary structures, the formation of a +hairy covering. Many such creatures existed +in the Triassic epoch—namely, the <i>Theromorpha</i>—some +of which indeed possess so +many characteristics which otherwise occur +in the Mammalia only, that these creatures +have been termed <i>Sauro-Mammalia</i>. However, +it has to be emphasized that none of +the Theromorpha hitherto discovered fulfils +all the requirements which would entitle them +to this important linking position. They only +give us an approximate idea of what this link +was like.</p> + +<p>18. Stage of the <i>Promammalia</i>, or <i>Prototheria</i>. +The only surviving members are +the famous duck-bill, Ornithorhynchus, and +the spiny ant-eaters, Echidna and Proechidna, +of the Australian region. These few genera, +however, differ so much from one another in +various important respects that they cannot +but be remnants of an originally much larger +group. Indeed, many fossils from the Upper<span class="pagenum"><a name="Page_65" id="Page_65">[Pg 65]</a></span> +Triassic and from the Jurassic strata have +without much doubt to be referred to the +Prototheria. The Prototheria are typical +mammals, because they possess the following +characteristics: The heart is completely +quadrilocular; the blood is warm, and its red +corpuscles have, owing to the loss of their +nucleus, been modified from biconvex into +biconcave discs; they have a hairy coat and +sweat glands, and two occipital condyles; the +ilio-sacral connection is preacetabular; the +ankle-joint is cruro-tarsal; the quadrate bone +of the Reptilia has ceased to carry the under +jaw, which now articulates directly with the +squamosal portion of the skull. Their low +position is shown by the retention of the +following reptilian features: Complete coracoid +bones and a T-shaped interclavicle; a +cloaca, or common chamber for the passage +of the fæces, the genital and the urinary products; +they are still oviparous; the embryo +develops without a chorion, and is therefore +not nourished through a placenta. Even the<span class="pagenum"><a name="Page_66" id="Page_66">[Pg 66]</a></span> +milk glands, which are absolutely peculiar to +the Mammalia, are still in a very primitive +stage, and do not yet produce milk proper; +and there is only a temporary shallow marsupium.</p> + +<p>19. Stage of <i>Metatheria</i>, or <i>Marsupialia</i>, +are direct descendants of Prototheria; but +they show higher development by the reduction +of the coracoid bones and the interclavicle. +The original cloaca is divided into +a rectal chamber and a uro-genital sinus, completely +separated, at least in the males; they +are viviparous; the young are received into +a permanent marsupium, in the walls of which +are formed typical milk glands and nipples, +but the embryo is still devoid of a placenta, +although some recent marsupials show indications +of such an organ. The corpus callosum +in the brain is still very weak.</p> + +<p>Most of the marsupials are extinct. They +occur from the Upper Trias onwards, and +had in the Jurassic epoch attained a wide +distribution both in Europe and in America.<span class="pagenum"><a name="Page_67" id="Page_67">[Pg 67]</a></span> +Since the Tertiary epoch they have been +restricted to America and to the Australian +region, and are now represented by about 150 +species.</p> + +<p>20. Stage of <i>Prochoriata</i>, or early <i>Placentalia</i>: +a further development of the Metatheria +by the development of a placenta, loss +of the marsupium and the marsupial bones, +complete division by the perineum of the +anal and uro-genital chambers, stronger +development of the corpus callosum, or chief +commissure of the two hemispheres of the +brain.</p> + +<p>Placentalia must have come into existence +during the Cretaceous epoch. Up to that +time all the Mammalia seem to have +belonged to either Prototheria or to Metatheria; +but in the early Eocene we can +distinguish the main groups of Placentalia—namely, +(1) Trogontia, now represented by +the rodents; (2) Edentata, or sloths, armadilloes, +etc.; (3) Carnassia, or Insectivora +and Carnivora; (4) Chiroptera, or bats;<span class="pagenum"><a name="Page_68" id="Page_68">[Pg 68]</a></span> +(5) Cetomorpha, or whales and dugongs; +(6) Ungulata; (7) Primates. Of these +groups, the first and second, third and fourth, +fifth and sixth, can perhaps, to judge from +palæontological evidence, be combined into +three greater groups, as indicated by the +fossil Esthonychida, Ictopsida, and Condylarthra, +in addition to the ancestral Primates, +or Lemuravida, as the fourth large branch of +the ancestral-tree where this has reached the +placental level. Among none of the first +three branches can we look for the ancestors +of the Primates. The Lemuravida, therefore, +represent a branch equivalent to the three +other branches.</p> + +<p>21. Stage of <i>Lemures</i>, or <i>Prosimiæ</i>, comprising +the older members of the Primates, +consequently approaching most nearly to the +Lemuravida. The limbs are modified into +pentadactyle hands and feet of the arboreal +type, and are protected by nails. The dentition +is of the frugivorous or omnivorous type, +with an originally complete series of teeth,</p> + +<p><span class="pagenum"><a name="Page_69" id="Page_69">[Pg 69]</a></span></p> + +<p><span class="pagenum"><a name="Page_70" id="Page_70">[Pg 70]</a></span></p> + +<p>with milk teeth and with permanent. The +orbit is surrounded by a complete bony ring, +posteriorly by a fronto-jugal arch, but still +widely communicating with the temporal +fossa. The placenta is diffuse and non-deciduous.</p> +<p class= "center"> +ANCESTRAL TREE OF THE MAMMALIA.<br /> + +<i>'Systematische Phylogenie,' § 386.</i></p> + +<table id="atm" summary="mammalia" cellspacing="0"> +<tr> + <td class="tdc"></td> + <td class="tdc"><i><small>Perissodactyla</small></i></td> + <td class="tdc" ></td> + <td class="tdc" ><i>Homo</i></td> + <td class="tdc" ></td> + <td class="tdc" ><small><i>Carnivora</i></small></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"><i><small>Artiodactyla</small></i></td> + <td class="tdc">|</td> + <td class="tdc">(<i><small>Litopterna</small></i>)</td> + <td class="tdc">|</td> + <td class="tdc"></td> + <td class="tdc"> |</td> + <td class="tdc"><small><i>Pinnipedia</i></small></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc"><i><small>Anthropoidae</small></i></td> + <td class="tdc"></td> + <td class="tdr">|——</td> + <td class="tdl"> ——'</td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdr">| —— </td> + <td class="tdl"> —— '</td> + <td class="tdc">|</td> + <td class="tdc"></td> + <td class="tdc">|</td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdr">'——</td> + <td class="tdl"> ——|</td> + <td class="tdc"></td> + <td class="tdc"><i><small>Catarhinæ</small></i></td> + <td class="tdc"></td> + <td class="tdc"><small><i>Carnassia</i></small></td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdr">'—— </td> + <td class="tdl"> —— ,</td> + <td class="tdc">|</td> + <td class="tdc"></td> + <td class="tdc">|</td> + <td class="tdc"><i><small>Chiroptera</small></i></td> +</tr> +<tr> + <td class="tdc"><small>(<i>Amblypoda</i>)</small></td> + <td class="tdc"><i><small>Proboscidea</small></i></td> + <td class="tdc">|</td> + <td class="tdc"><i><small>Platyrhinæ</small></i></td> + <td class="tdc"><i><small>Insectivora</small></i></td> + <td class="tdc">|</td> + <td class="tdc">|</td> +</tr> +<tr> + <td class="tdr">'——</td> + <td class="tdl">——|</td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdr">|——</td> + <td class="tdl"> ——'</td> + <td class="tdc">|</td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdr">' —— </td> + <td class="tdl"> —— |</td> + <td class="tdc"><i><small>Simiæ</small></i></td> + <td class="tdc">|</td> + <td class="tdc"></td> + <td class="tdc">|</td> +</tr> +<tr> + <td class="tdc"><small><i>Cetacea</i></small></td> + <td class="tdc"><i><small>Sirenia</small></i></td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdr">|——</td> + <td class="tdc">————</td> + <td class="tdl">——'</td> +</tr> +<tr> + <td class="tdr">|—— </td> + <td class="tdl">——'</td> + <td class="tdc">|</td> + <td class="tdc"><i><small>Lemures</small></i></td> + <td class="tdc">|</td> + <td class="tdc"><i><small>Rodentia</small></i></td> + <td class="tdl"></td> +</tr> +<tr> + <td class="tdc"><i><small>Cetomorpha</small></i></td> + <td class="tdc"></td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdl"></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc"><i><small>Hyracoidea</small></i></td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdr"><i><span class="u"><small>Ictopsales</small></span></i></td> + <td class="tdc">(<i><small>Tillodontia</small></i>)</td> + <td class="tdl"></td> +</tr> +<tr> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc"><i><span class="u"><small>Lemuravidæ</small></span></i></td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdr">'——</td> + <td class="tdc">——'——</td> + <td class="tdl"> —— |</td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc"><i><small>Trogontia</small></i></td> + <td class="tdc"><i><small>Edentata</small></i></td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"><i><span class="u"><small>Condylarthrales</small></span></i></td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdr">|——</td> + <td class="tdl"> ——'</td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc">|</td> + <td class="tdc"><i><span class="u"><small>Esthonychales</small></span></i></td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdr">' —— </td> + <td class="tdr">——|——</td> + <td class="tdc">——'——</td> + <td class="tdl">——'</td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc">|</td> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdc" colspan="7">Eutheria s. Placentalia</td> + </tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc">|</td> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdc" colspan="3"><i><small>Marsupialia diprotodontia</small></i></td> + <td class="tdc">|</td> + <td class="tdc" colspan="3"><i><small>Marsupialia polyprotodontia</small></i></td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdr">'——</td> + <td class="tdc">————</td> + <td class="tdc">——|——</td> + <td class="tdc">————</td> + <td class="tdl">——'</td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdc" colspan="7">Metatheria</td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc">|</td> + <td class="tdc"><i><small>Monotremata</small></i></td> + <td class="tdc"></td> + <td class="tdc"><small>(<i>Allotheria</i>)</small></td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc">Prototheria</td> + <td class="tdc">|</td> + <td class="tdc"></td> + <td class="tdc">|</td> +</tr> +<tr> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdc"></td> + <td class="tdr">|——</td> + <td class="tdl">——'——</td> + <td class="tdc">————</td> + <td class="tdl">——'</td> +</tr> +<tr> + <td class="tdc" colspan ="7"><i><span class="u"><small>Hypotheria s. Promammalia</small></span></i></td> +</tr> +</table> +<p> +<i>Names in brackets indicate extinct groups.<br /> +Names <span class="u">underlined</span> indicate hypothetical groups or combinations.</i><br /> +</p> + +<p>22. Stage of <i>Simiæ</i>. Orbit completely +separated from the temporal fossa by an +inward extension of the frontal and malar +bones meeting the alisphenoid. Placenta consolidated +into a disc, and with a maternal +deciduous portion. Mammæ pectoral only. +The dental formula is 2.1.3.3. All the +fingers and toes are protected by flat nails. +The tail is long. The American prehensile-tailed +monkeys are a lower side-branch.</p> + +<p>23. Stage of <i>Catarrhinæ Cercopithecidæ</i>. +The dental formula is 2.1.2.3, owing to the +loss of one pair of premolars in each jaw. +The frontal and alisphenoid bones are in +contact, separating the parietal from the +malar bone; this feature is correlated with +the enlarged brain. The internarial septum<span class="pagenum"><a name="Page_71" id="Page_71">[Pg 71]</a></span> +is narrow, and the nostrils look forwards and +downwards instead of sidewards—hence the +term 'Catarrhinæ.' The external auditory +meatus is long and bony. The tail is long, +with the exception of <i>Macacus inuus</i>. The +body is covered with a thick coat of furry +hair. Catarrhine monkeys have existed, we +know with certainty, since the Miocene.</p> + +<p>24. Stage of <i>Catarrhinæ Anthropoidæ</i>, or +<i>Apes</i>. Now represented by the large apes—namely, +the Hylobates or gibbon of South-Eastern +Asia, <i>Simia satyrus</i>, the orang-utan +of Sumatra and Borneo, <i>Troglodytes gorilla</i>, +<i>T. niger</i> and <i>T. calvus</i>, the gorilla and the +chimpanzees from Western Equatorial Africa. +Of fossils are to be mentioned Pliopithecus +and Dryopithecus from European Miocene, +and <i>Troglodytes sivalensis</i> from the Pliocene +of the Punjaub. The tail is reduced to a +few caudal vertebræ, which are transformed +into a coccyx, not visible externally; but in +the embryos of apes and man the tail is still +a conspicuous feature. The walk is semi<span class="pagenum"><a name="Page_72" id="Page_72">[Pg 72]</a></span>erect; +in adaptation to the prevailing arboreal +life, the arms are longer than the legs. +The hair of the body is considerably more +scanty than in the tailed monkeys. <i>Troglodytes +calvus</i>, a species or variety of chimpanzee, +is bald-headed. None of the recent +genera of apes can lay claim to a place in +the ancestry of mankind.</p> + +<p>25. Stage of <i>Pithecanthropi</i>. Hitherto the +only known representative is <i>Pithecanthropus +erectus</i>, from the Upper Pliocene of Java. In +adaptation to a more erect gait, the legs have +become stronger and the hind-hand has been +turned into a flat-soled walking 'foot.' The +brain is considerably enlarged. Presumably +it is still devoid of so-called articulate speech; +this is indicated by the fact that children +have to learn the language of their parents, +and by the circumstance that comparative +philology declares it impossible to reduce the +chief human languages to anything like one +common origin.</p> + +<p>26. <i>Man.</i> Known with certainty to have<span class="pagenum"><a name="Page_73" id="Page_73">[Pg 73]</a></span> +existed as an implement-using creature in the +last Glacial epoch. His probable origin +cannot, therefore, have been later than the +beginning of the Plistocene. The place of +origin was probably somewhere in Southern +Asia.</p> + +<p>Whilst we have to admit that there are +great defects in the older (invertebrate) +portion of our pedigree, we have all the more +reason to be satisfied with the positive results +of our investigation of the more recent (vertebrate) +part of it. All modern researches have +confirmed the views of Lamarck, Darwin, and +Huxley, and they allow of no doubt that the +nearest vertebrate ancestors of mankind were +a series of Tertiary Primates.</p> + +<p>Particularly valuable are the admirable +attempts of the two zoologists, Paul and Fritz +Sarasin,<a name="FNanchor_23_23" id="FNanchor_23_23"></a><a href="#Footnote_23_23" class="fnanchor">[23]</a> to throw light upon the human +phylogeny by painstaking comparison of all +the skeletal parts of man with those of the<span class="pagenum"><a name="Page_74" id="Page_74">[Pg 74]</a></span> +anthropoid apes. They have shown that +among the lower races of man the primitive +Veddahs of Ceylon approach the apes most +nearly, and that among the latter the chimpanzee +stands nearest to man.</p> + +<p>The direct descent of man from some +extinct ape-like form is now beyond doubt, +and admits of being traced much more clearly +than the origin of many another mammalian +order. The pedigrees of the Elephants, +the Sirenia, the Cetacea, and, above all, of +the Edentata, for example, are much more +obscure and difficult to explain. In many +parts of their organization—for example, in +the number and structure of his five digits and +toes—man and monkeys have remained much +more primitive than most of the Ungulata.</p> + +<p>The immense significance of this positive +knowledge of the origin of man from some +Primate does not require to be enforced. Its +bearing upon the highest questions of philosophy +cannot be exaggerated. Among modern +philosophers no one has perceived this more<span class="pagenum"><a name="Page_75" id="Page_75">[Pg 75]</a></span> +deeply than Herbert Spencer.<a name="FNanchor_24_24" id="FNanchor_24_24"></a><a href="#Footnote_24_24" class="fnanchor">[24]</a> He is one of +those older thinkers who before Darwin were +convinced that the theory of development +is the only way to solve the 'enigma of the +world.' Spencer is also the champion of those +evolutionists who lay the greatest weight +upon <i>progressive heredity</i>, or the much combated +<i>heredity of acquired characters</i>. From +the first he has severely attacked and criticised +the theories of Weismann, who denies +this most important factor of phylogeny, and +would explain the whole of transformism by +the 'all-sufficiency of selection.' In England +the theories of Weismann were received with +enthusiastic acclamation, much more so than +on the Continent, and they were called 'Neo-Darwinism,' +in opposition to the older conception +of Evolution, or 'Neo-Lamarckism.' +Neither of those expressions is correct. +Darwin himself was convinced of the fundamental +importance of progressive heredity<span class="pagenum"><a name="Page_76" id="Page_76">[Pg 76]</a></span> +quite as much as his great predecessor +Lamarck; as were also Huxley and Spencer.</p> + +<p>Three times I had the good fortune to +visit Darwin at Down, and on each occasion +we discussed this fundamental question in +complete harmony. I agree with Spencer +in the conviction that progressive heredity is +an indispensable factor in every true monistic +theory of Evolution, and that it is one of its +most important elements. If one denies +with Weismann the heredity of acquired +characters, then it becomes necessary to have +recourse to purely mystical qualities of germ-plasm. +I am of the opinion of Spencer, that +in that case it would be better to accept a +mysterious creation of all the various species +as described in the Mosaic account.</p> + +<p>If we look at the results of modern anthropogeny +from the highest point of view, and +compare all its empirical arguments, we are +justified in affirming that <i>the descent of man +from an extinct Tertiary series of Primates +is not a vague hypothesis, but an historical fact</i>.</p> + +<p><span class="pagenum"><a name="Page_77" id="Page_77">[Pg 77]</a></span></p> + +<p>Of course, this fact cannot be proved +<i>exactly</i>. We cannot explain all the innumerable +physical and chemical processes, +all the physiological mutations, which have +led during untold millions of years from the +simplest Monera and from the unicellular +Protista upwards to the chimpanzee and to +man. But the same consideration applies to +all historical facts. We all believe that +Aristotle, Cæsar, and King Alfred did live; +but it is impossible to give a proof within +the meaning of modern exact science. We +believe firmly in the former existence of +these and other great heroes of thought, +because we know well the works they have +left behind them, and we see their effects in +the history of human culture. These indirect +arguments do not furnish stronger evidence +than those of our history as vertebrates. +We know of many Jurassic mammals only +a single bone, the under jaw. We all +believe that these mammals possessed also +an upper jaw, a skull, and other bones. But<span class="pagenum"><a name="Page_78" id="Page_78">[Pg 78]</a></span> +the so-called 'exact school,' which regards +the transformation of species as a hypothesis +not proven, must suppose that the +mandibula was the only bone in the body of +these curious animals.</p> + +<p>Looking forward to the twentieth century, +I am convinced that it will universally accept +our theory of descent, and that future science +will regard it as the greatest advance made +in our time. I have no doubt that the +influence of the study of anthropogeny upon +all other branches of science will be fruitful +and auspicious. The work done in the +present century by Lamarck and Darwin +will in all future times be considered one +of the greatest conquests made by thinking +man.</p> + +<p><span class="pagenum"><a name="Page_79" id="Page_79">[Pg 79]</a></span></p> + +<p class="center">EVOLUTIONARY STAGES OF THE PRINCIPAL +GROUPS OF VERTEBRATA.<a name="FNanchor_25_25" id="FNanchor_25_25"></a><a href="#Footnote_25_25" class="fnanchor">[25]</a> </p> +<table id="esv" summary="stages"> +<tr> + <td class="tdc"><small>STAGES OF THE</small></td> + <td class="tdc"><small> CLASSES.</small></td> + <td class="tdc"><small>STAGES OF THE HEART.</small></td> +</tr> +<tr> + <td class="tdc"><small>PAIRED LIMBS.</small></td> + <td class="tdc"></td> + <td class="tdc"></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{1. <i>Acrania.</i></td> + <td class="tdl">I. <i>Leptocardia.</i></td> +</tr> +<tr> + <td class="tdl">I. <i>Adactylia</i></td> + <td class="tdl">{</td> + <td class="tdl"> Cold-blooded; heart</td> +</tr> +<tr> + <td class="tdl"> s. <i>Impinnata</i>.</td> + <td class="tdl">{</td> + <td class="tdl"> with one chamber;</td> +</tr> +<tr> + <td class="tdl"> Without jaws</td> + <td class="tdl">{</td> + <td class="tdl"> without lungs.</td> +</tr> +<tr> + <td class="tdl"> and limbs.</td> + <td class="tdl">{</td> + <td class="tdl"></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{2. <i>Cyclostomata.</i></td> + <td class="tdl">}II. <i>Ichthyocardia.</i></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} Cold-blooded; heart</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} two-chambered, with</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} one atrium and one</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} ventricle; heart</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} containing venous</td> +</tr> +<tr> + <td class="tdl">II. <i>Polydactylia</i></td> + <td class="tdl">{3. <i>Pisces.</i></td> + <td class="tdl">} blood only; without lungs</td> +</tr> +<tr> + <td class="tdl"> s. <i>Pinnata</i>.</td> + <td class="tdl">{</td> + <td class="tdl"></td> +</tr> +<tr> + <td class="tdl"> With two</td> + <td class="tdl">{</td> + <td class="tdl"></td> +</tr> +<tr> + <td class="tdl"> pairs of fins.</td> + <td class="tdl">{ 4. <i>Dipnoi.</i></td> + <td class="tdl">}III. <i>Amphicardia.</i></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl"> }Cold-blooded; heart</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} with three complete</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} chambers, namely, with</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl">} two atria and one</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{ 5. <i>Amphibia.</i></td> + <td class="tdl">} ventricle, or (Reptilia)</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{</td> + <td class="tdl">} two ventricles with still</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{</td> + <td class="tdl">} incomplete septum; heart</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{</td> + <td class="tdl">} containing mixed venous</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{</td> + <td class="tdl">} and arterialized</td> +</tr> +<tr> + <td class="tdl">III. <i>Pentadactylia</i></td> + <td class="tdl">{ 6. <i>Reptilia.</i></td> + <td class="tdl">} blood; with lungs.</td> +</tr> +<tr> + <td class="tdl"> s. <i>Tetrapoda</i>.</td> + <td class="tdl">{</td> + <td class="tdl"></td> +</tr> +<tr> + <td class="tdl"> With two</td> + <td class="tdl">{</td> + <td class="tdl">{IV. <i>Thermocardia.</i></td> +</tr> +<tr> + <td class="tdl"> pairs of</td> + <td class="tdl">{</td> + <td class="tdl">{ Warm-blooded; heart</td> +</tr> +<tr> + <td class="tdl"> pentadactyle</td> + <td class="tdl">{</td> + <td class="tdl">{ with four complete</td> +</tr> +<tr> + <td class="tdl"> limbs (unless</td> + <td class="tdl">{7. <i>Aves.</i></td> + <td class="tdl">{ chambers, namely, two</td> +</tr> +<tr> + <td class="tdl"> they have</td> + <td class="tdl">{</td> + <td class="tdl">{ auricles and two</td> +</tr> +<tr> + <td class="tdl"> been lost by</td> + <td class="tdl">{</td> + <td class="tdl">{ ventricles; right half</td> +</tr> +<tr> + <td class="tdl"> reduction).</td> + <td class="tdl">{</td> + <td class="tdl">{ of the heart with venous,</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{</td> + <td class="tdl">{ left half with arterialized,</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">{8. <i>Mammalia.</i></td> + <td class="tdl">{ blood; with lungs.</td> +</tr> +</table> + + +<p><span class="pagenum"><a name="Page_80" id="Page_80">[Pg 80]</a></span></p> + +<hr class="chap"/> +<div class="chapter-beginning"/> +<h2>BIOGRAPHICAL SKETCHES</h2> + + +<p><span class="smcap"><a name="Footnote_40" id="Footnote_40"></a><a href="#FNanchor_40">Jean Baptiste de Monet</a>, Chevalier de +<a name="Footnote_44" id="Footnote_44"></a><a href="#FNanchor_44">Lamarck</a></span>, was born on August 1, 1744, in +Picardy, where his father owned land. +Originally educated for the Church, he +soon enlisted, and distinguished himself in +active service. Owing to an accident affecting +his health, the young Lieutenant gave +up the military career, and, without means, +studied medicine and natural sciences at +Paris. In 1778 appeared his 'Flore française.' +In 1793 he was appointed to a +Chair of Zoology at the newly-formed Musée +d'Histoire Naturelle. He had the misfortune +to become gradually blind, and the last years +of his life were spent amid straitened circumstances. +He died in 1829.</p> + +<p><span class="pagenum"><a name="Page_81" id="Page_81">[Pg 81]</a></span></p> + +<p>In 1794 Lamarck divided the whole animal +kingdom into vertebrate and invertebrate +animals, and founded successively the groups +of Crustacea, Arachnida, Annelida, and +Radiata. Between 1816 and 1822 he published +his celebrated 'Histoire naturelle des +Animaux sans Vertèbres.'</p> + +<p>His most famous work is the 'Philosophie +zoologique,' 1809.</p> + +<p>Assuming the spontaneous origin of life, +he propounded the doctrine that all animals +and plants have arisen from low forms +through incessant modifications and changes. +In this respect he was in absolute opposition +to Cuvier, who upheld the immutability of +species, and did his best by absolute silence +to suppress the spread of the new doctrine.</p> + +<p>Lamarck has explained his views of transformism +chiefly in the seventh chapter of the +first volume of his 'Philosophie zoologique.'</p> + +<p>Organisms strive to accommodate or adapt +themselves to new circumstances, or to satisfy +new requirements—<i>e.g.</i>, climate, mode of<span class="pagenum"><a name="Page_82" id="Page_82">[Pg 82]</a></span> +procuring food, escape from enemies. The +continued function of parts of an organism +changes the old and produces new organs. +The acquirements are inherited by the offspring, +and thus are produced the more complicated +from simpler organisms. Continued +disuse brings about degeneration and ultimate +loss of an organ.</p> + +<p>Lamarck consequently sees in the adaptability, +or power of adaptation, which he +assumes for all living matter the ultimate +cause of variation; and, as he was certainly +the first to point out that acquired characters +are inherited by the progeny, he has given +a working explanation of Evolution.</p> + +<p>But his doctrine did not spread—partly +because he was misunderstood. His theory, +that a new want, by making itself felt, exacts +from the animal new exertions, perhaps from +parts hitherto not used, until the want is +satisfied—this way of putting it sounds too +teleological to explain the yearned-for change +in a mechanical or natural way. Moreover,<span class="pagenum"><a name="Page_83" id="Page_83">[Pg 83]</a></span> +many of his examples lacked the exact basis +of experiment and observation necessary for +their acceptance. Witness that of the neck of +the giraffe,—a never-failing source of ridicule +to men who cannot see the deeper purpose +underlying the well-meant attempt at an explanation, +which failed from want of complete +knowledge of the intricate circumstances.</p> + +<p>However, the theory of transformism was, +so to speak, in the air; and various authors +have written on the subject, filling the gap +between Lamarck and Darwin, especially +Goethe, Treviranus, Leopold von Buch, +and Herbert Spencer. But it is Darwin's +immortal merit to have opened our eyes by +his theory of natural selection, which is, at +least, the first attempt to explain some of the +causes and incidents of organic Evolution +in a natural mechanical way. Moreover, he +was the first clearly to express the fundamental +principles of the theory of descent, to +elaborate what had been at best a general +sketch of an ill-defined problem, and to enter<span class="pagenum"><a name="Page_84" id="Page_84">[Pg 84]</a></span> +into detail, supported by a host of painstaking +observations, the making of which had +taken him half a lifetime. Darwin, without +going further than cursorily into the causes +of variation, argued as follows: We know +that variations do occur in every kind of +living creatures. Some of these variations +lead to something, while others do not. An +enormously greater number of animals and +plants are born than reach maturity and can +in their turn continue the race. What is the +regulating factor? His answer is, The +struggle for existence—in other words, the +weeding out of the less fit, or rather of the +owners of those variations which are not so +well adapted to their surroundings.</p> + +<p>For 'adapted' we had better read 'adaptable,' +because a variation which does not +answer, which cannot be made use of, or, +still more notably, is a hindrance or disadvantage, +does not become an adapted +feature. There is often a confusion between +adaptation as an accomplished fact, a feature,<span class="pagenum"><a name="Page_85" id="Page_85">[Pg 85]</a></span> +or resultant condition, and adaptation as the +mode of fitting the organism to, or making +the best of, the prevailing surroundings or +circumstances.</p> + + +<p><span class="smcap">Étienne Geoffroy Saint-Hilaire</span> was +born in 1772 at Étampes, Seine-et-Oise. +He was originally brought up for the Church; +but when already ordained he attended +lectures on natural science and medicine in +Paris. He managed to get the place of +assistant in the Musée d'Histoire Naturelle; +he became Professor of Zoology in 1793, and +took the opportunity of encouraging young +Cuvier. Later he became Professor of +Zoology of the Faculté des Sciences, and in +1818 he published his remarkable 'Philosophie +anatomique.' He died in 1844.</p> + +<p>He had conceived the 'unity of organic +composition,' meaning that there is only one +plan of construction,—the same principle, but +varied in its accessory parts. In 1830, when +Geoffroy proceeded to apply to the Inverte<span class="pagenum"><a name="Page_86" id="Page_86">[Pg 86]</a></span>brata +his views as to the uniformity of +animal composition, he found a vigorous +opponent in Cuvier. Geoffroy, like Goethe, +held that there is in Nature a law of compensation, +or balancing of growth, so that if +one organ take on an excess of development, +it is at the expense of another part; and he +maintained that, since Nature takes no +sudden leaps, even organs which are superfluous +in any given species, if they have +played an important part in other species of +the same family, are retained as rudiments, +which testify to the permanence of the +general plan of creation. It was his conviction +that, owing to the conditions of life, +the same forms had <i>not</i> been perpetuated +since the origin of all things, although it was +not his belief that existing species were becoming +modified. Cuvier, on the other +hand, maintained the absolute invariability +of species, which, he declared, had been +created with regard to the circumstances in +which they were placed, each organ con<span class="pagenum"><a name="Page_87" id="Page_87">[Pg 87]</a></span>trived +with a view to the function it had to +fulfil,—thus putting the effect for the cause +('Encyclopædia Britannica,' 9th edition, +vol. xxi., p. 171).</p> + + +<p><span class="smcap">George <a name="Footnote_46" id="Footnote_46"></a><a href="#FNanchor_46">Cuvier</a></span> +in the department of Doubs, which +at that time belonged to Württemberg. He +was educated at Stuttgart, and studied +political economy. While acting as private +tutor to a French family in France he +followed his favourite pursuit, the study of +natural sciences. Geoffroy Saint-Hilaire +heard of him, and appointed him assistant in +the department of comparative anatomy in the +Musée d'Histoire Naturelle. In 1799 he was +elected Professor of Natural History at the +Collège de France, and soon after he became +Perpetual Secretary of the Institut National. +In 1831, a year before his death, Louis +Philippe raised him to the rank of a peer of +France.</p> + +<p>Cuvier was the first to indicate the true<span class="pagenum"><a name="Page_88" id="Page_88">[Pg 88]</a></span> +principle upon which the natural classification +of animals should be based—namely, +their structure. It is the study of the +anatomy of the creatures and their comparison +which affords the only sound basis +of a classification. The work which had the +greatest influence upon the scientific public +is his 'Règne animal distribué d'après son +Organisation,' 1817. The system which he +propounded in this book gradually came to +have almost world-wide fame, and, in spite +of its many obvious deficiencies, still lingers +in some of our most recent text-books.</p> + +<p>A standard work is his 'Leçons d'Anatomie +comparée,' and, in truth, he is the founder +of that kind of comparative anatomy which +was brought to such a high state by his +pupil, the late Sir Richard Owen. Cuvier +discovered the law of 'correlation of growth,' +and was the first to apply this law to the +reconstruction of animals from fragments: +see his monumental work entitled 'Recherches +sur les Ossemens fossiles,' 1812.</p> + +<p><span class="pagenum"><a name="Page_89" id="Page_89">[Pg 89]</a></span></p> + +<p>Cuvier, however, as a strict matter-of-fact +man, was incapable of appreciating the speculative +conclusions which were drawn by his +contemporaries Saint-Hilaire and Lamarck. +On the contrary, he firmly stuck to the +doctrine of the immutability of species; and, +in order to account for the existence of +animals whose kind exists no longer, he invented +the famous doctrine of successive +cataclysms.</p> + + +<p><span class="smcap">Karl Ernst <a name="Footnote_41" id="Footnote_41"></a><a href="#FNanchor_41">von Baer</a></span> +was born in 1792 +in Esthonia, studied at Dorpat and then at +Würzburg, where Döllinger introduced him +to comparative anatomy. For a few years +he was a <i>Privat-docent</i> at Berlin; then he +went to Königsberg as Professor of Zoology +and Embryology. In 1834 he became an +Academician at St. Petersburg, where for +many years he was occupied with the most +varied studies, chiefly geographical and +ethnological. The last years of his long, +active life he spent in contemplative retire<span class="pagenum"><a name="Page_90" id="Page_90">[Pg 90]</a></span>ment +on his paternal estate, and he died at +Dorpat in 1876.</p> + +<p>While still at Würzburg he induced his +friend Pander, a young man of means, to study +the development of the chick; and Pander was +the first to start the theory of the germinal +layers from which all the organs arise. +Baer, however, continued these researches in +Königsberg, and after nine years' labour produced +his epoch-making work, 'Ueber Entwicklungsgeschichte +der Thiere: Beobachtung +und Reflexion,' Königsberg, 1828. Nine +years later he completed the second volume. +He established upon a firm basis the theory +of the germinal layers, and by further 'reflexions' +arrived at the elucidation of some of +the most fundamental laws of biology. For +example, in the first volume he made the +following prophetic statement: 'Perhaps all +animals are alike, and nothing but hollow +globes at their earliest developmental beginning. +The farther back we trace their +development, the more resemblance we find<span class="pagenum"><a name="Page_91" id="Page_91">[Pg 91]</a></span> +in the most different creatures. And this +leads to the question whether at the beginning +of their development all animals are essentially +alike, and referable to one common ancestral +form. Considering that the "germ" (which +at a certain stage appears in the shape of a +hollow globe or bag) is the undeveloped animal +itself, we are not without reason for assuming +that the common fundamental form is that of a +simple vesicle, from which every animal is +evolved, not only theoretically, but historically.'</p> + +<p>This statement is all the more wonderful +when we consider that the cells, the all-composing +individual units, were not discovered +until ten years later.</p> + +<p>In 1829 Baer discovered the human egg, +and later the chorda dorsalis. In an address +delivered in 1834, entitled 'The Most Universal +Law of Nature in all Development,' he +explained that only from a most superficial +point of view can the various species be looked +upon as permanent and immutable types;<span class="pagenum"><a name="Page_92" id="Page_92">[Pg 92]</a></span> +that, on the contrary, they can be nothing +but passing stages, or series of stages, of +development, which have been evolved by +transformation out of common ancestral forms.</p> + + +<p><span class="smcap">Johannes Mueller</span>, born at Coblenz in +1801, established himself as <i>Privat-docent</i> at +Bonn, where in 1830 he became Professor of +Physiology. In 1833 he accepted the Chair +of Anatomy and Physiology at Berlin, where +he died in 1858.</p> + +<p>He was one of the most distinguished +physiologists and comparative anatomists. +By summarizing the labours and discoveries +already made in the field of physiology, by +reducing them to order, and abstracting the +general principles, he became the founder of +modern physiology. But he was scarcely +less distinguished by his researches in +comparative anatomy. His 'Vergleichende +Anatomie der Myxinoiden,' in <i>Abhandlungen +der Berliner Akademie</i>, 1835-45, and 'Ueber +die Grenzen der Ganoiden' (<i>ibid.</i>, 1846), are +standard works of lasting value.</p> + +<p><span class="pagenum"><a name="Page_93" id="Page_93">[Pg 93]</a></span></p> + +<p>Mueller exercised a stimulative influence +as a teacher. Many well-known men—such +as Helmholtz, Gegenbaur, Bruecke the physiologist, +Guenther the zoologist, Virchow the +pathologist, Koelliker and Haeckel—have +been his pupils.</p> + + +<p><span class="smcap">Rudolph <a name="Footnote_45" id="Footnote_45"></a><a href="#FNanchor_45">Virchow</a></span> +Schievelbein, a small town in Eastern +Pomerania. He studied medicine in Berlin +as a pupil of Johannes Mueller, and went +in 1849 to Würzburg, where, under the +influence of Koelliker, and Leydig the pathologist, +he laid the foundation of an entirely +new branch of medical science—that of +'cellular pathology.' Since 1856 he has +filled the principal Chair of Pathology at +Berlin. In 1892 he received the Copley +medal of the Royal Society.</p> + +<p>'His contributions to the study of morbid +anatomy have thrown light upon the diseases +of every part of the body; but the broad +and philosophical view he has taken of the<span class="pagenum"><a name="Page_94" id="Page_94">[Pg 94]</a></span> +processes of pathology has done more than +his most brilliant observations to make the +science of disease.</p> + +<p>'In pathology, strictly so called, his two +great achievements—the detection of the +cellular activity which lies at the bottom of +all morbid as well as normal physiological +processes, and the classification of the important +group of new growths on a natural +histological basis—have each of them not +only made an epoch in medicine, but have +also been the occasion of fresh extension of +science by other labourers' (Proc. Royal +Soc., 1892).</p> + +<p>Virchow has not confined himself to +medicine. He takes the keenest interest in +anthropology and ethnology, on which subjects +he has contributed many papers. +Together with his colleagues Helmholtz the +physicist, and Du Bois Reymond the physiologist, +he has taken a leading place in the +spreading of natural science; but, unfortunately, +he did not take to the doctrine of<span class="pagenum"><a name="Page_95" id="Page_95">[Pg 95]</a></span> +Evolution, and for the last thirty years has +been its declared antagonist, rarely missing +an opportunity of denouncing everything but +descriptive anatomy and zoology as the +unsound speculations of dreamers. This has +on more than one occasion brought him into +sharp conflict with Haeckel. His activity is +astonishing, especially if it be remembered that +Virchow has for many years been one of the +most conspicuous leaders of the Progressists +and Radicals in the German Parliament and +Berlin town-council.</p> + + +<p><span class="smcap">Edward Drinker Cope</span> was born at +Philadelphia, Pa. After studying at several +Continental Universities, especially at Heidelberg, +he became first Professor of Natural +Science at Haverford College, and later +Professor of Geology and Mineralogy. He +died at an early age in 1897. As a member +of various geological expeditions and other +surveys, he explored chiefly Kansas, Wyoming, +and Colorado; and he published many<span class="pagenum"><a name="Page_96" id="Page_96">[Pg 96]</a></span> +most suggestive papers on the fossil vertebrate +fauna of North America, and on classification +especially of Amphibia and Reptiles.</p> + +<p>Among works of a more general philosophical +scope may be mentioned 'The +Origin of the Fittest,' 1887, and his latest +work, 'The Primary Factors of Organic +Evolution,' 1896.</p> + + +<p><span class="smcap">Albert von <a name="Footnote_50" id="Footnote_50"></a><a href="#FNanchor_50">Koelliker</a></span> +became Professor of Anatomy at Würzburg. +His earlier studies and discoveries contributed +considerably to the systematic development +of the cell theory. In 1844 he observed the +division and further multiplication of the +original egg cell. Next year he showed the +continuity between nerve cells and nerve +fibres in the Vertebrata; later, that the non-striped +or smooth muscular tissue is composed +of cellular elements. He demonstrated that +the Gregarinæ are unicellular creatures. In +1852 he went with his younger friend Gegenbaur +to Messina, where he studied especially<span class="pagenum"><a name="Page_97" id="Page_97">[Pg 97]</a></span> +the development of the Cephalopoda (cuttlefishes +and allies); and he produced a magnificent +work on Alcyonaria, Medusæ, and +other allied forms. He elucidated the development +of the vertebral column, especially +with reference to the notochord.</p> + +<p>In 1848 he founded, together with Th. von +Siebold, the famous <i>Zeitschrift für wissenschaftliche +Zoologie</i>.</p> + +<p>A standard work on mammalian embryology +is his 'Entwicklungsgeschichte +des Menschen und der höheren Thiere,' a +text-book of which the second edition +appeared in 1879.</p> + +<p>At the anniversary meeting of 1897 he +received the Copley medal, the highest honour +which the Royal Society can bestow.</p> + + +<p><span class="smcap">Carl <a name="Footnote_49" id="Footnote_49"></a><a href="#FNanchor_49">Gegenbaur</a> +</span> was born on August 21, +1826, in Bavaria. He studied medicine and +kindred subjects in Würzburg, and as a pupil +of Johannes Mueller in Berlin.</p> + +<p>In 1852 he went with Koelliker to Messina<span class="pagenum"><a name="Page_98" id="Page_98">[Pg 98]</a></span> +to study the structure and development of the +marine fauna. Important papers on Siphonophora, +Echinoderms, Pteropoda, and, later, +Hydrozoa and Mollusca, were the result. +Soon after his return he was offered the +chair of Anatomy at Jena, and at this retired +spot he produced his most important works, +devoting himself more and more to the study +of the Vertebrata. Since 1875 he has held +the Chair of Anatomy at Heidelberg.</p> + +<p>In 1859 he published his 'Principles of +Comparative Anatomy'; but in 1870 he remodelled +it completely, the theory of descent +being the guiding principle. These 'Grundzüge' +were followed by a somewhat more +condensed 'Grundriss,' the second edition of +which was published in 1878, and has been +translated into French and English. In the +meantime he had broken new ground by +the development and treatment of certain +problems concerning the composition and +origin of the limbs, the shoulder-girdle and +the skull, researches which are embodied<span class="pagenum"><a name="Page_99" id="Page_99">[Pg 99]</a></span> +in his 'Untersuchungen zur vergleichenden +Anatomie der Wirbelthiere,' 1864-65-72.</p> + +<p>In 1883 he brought out a text-book on +human anatomy. This also marked a new +epoch, because for the first time, not only the +nomenclature, but also the general treatment +of human anatomy, was put upon a firm +comparative anatomical basis. The success +of this work is indicated by the fact that it +reached the sixth edition in 1897.</p> + +<p>Lastly, in 1898, appeared the first volume +of what may be called his crowning work, +'Vergleichende Anatomie der Wirbelthiere.'</p> + +<p>Gegenbaur is universally recognised, not +only as the greatest living comparative +anatomist, but also as the founder of the +modern side of this science, by having based +it on the theory of descent.</p> + +<p>In 1896 he received from the Royal Society +the Copley medal 'for his pre-eminence in +the science of comparative anatomy or animal +morphology.'</p> + +<p>His marvellously powerful influence as a<span class="pagenum"><a name="Page_100" id="Page_100">[Pg 100]</a></span> +teacher and investigator has made Heidelberg +a centre whence many pupils have +spread his teaching, and above all his method +of research.</p> + + +<p><span class="smcap">Ernst Heinrich Haeckel</span> was born on +February 16, 1834, at Potsdam. He carried +out his academical studies alternately at +Berlin and Würzburg, attracted by such +men as Johannes Mueller, Koelliker, and +Virchow. For years he was undecided what +his career should be, whether that of botanist, +collector, or geographical traveller. Certainly +that of medicine attracted him least, although +in deference to his father's wishes he qualified +and settled down for a year's practice in +Berlin. As he himself has told us, he might +perhaps have proved rather successful as a +physician, to judge from the fact that he did +not lose a single patient. But 'I had only +three patients all told, and the reason of this +is perhaps that I had given on my plate the +hours of consultation as from 5 to 6 <i>a.m.</i>'</p> + +<p><span class="pagenum"><a name="Page_101" id="Page_101">[Pg 101]</a></span></p> + +<p>During the year 1859 he travelled as +medical man and artist in Sicily. In 1861 +he was induced by Gegenbaur, whose acquaintance +he had made in Würzburg, to +establish himself as a <i>Privat-docent</i> for comparative +anatomy in Jena. And there he +has remained ever since, filling the Chair of +Zoology, and having declined several much +more tempting offers from the Universities of +Würzburg, Vienna, Strassburg, and Bonn.</p> + +<p>Within one year, 1865, he wrote the two +volumes of his 'Generelle Morphologie der +Organismen,' as he himself relates, in order +to master his sorrow over the loss of his first +wife. But he broke down, and went to the +Canaries to recruit health and strength. The +'Morphologie,' which has long been out of +print,<a name="FNanchor_26_26" id="FNanchor_26_26"></a><a href="#Footnote_26_26" class="fnanchor">[26]</a> made scarcely any impression. It<span class="pagenum"><a name="Page_102" id="Page_102">[Pg 102]</a></span> +was ignored, probably because he had placed +the old-fashioned study of zoology and morphology +upon a thoroughly Darwinistic basis.</p> + +<p>On the advice of his friend Gegenbaur, he +gave a more popularly written abstract of +his 'Generelle Morphologie'—in fact, the +substance of a series of his lectures—in +the shape of his 'Natürliche Schöpfungsgeschichte.' +This 'History of Natural +Creation,' which in 1898 has reached the +ninth edition (first edition translated into +English in 1873), had the desired effect. +So also had his '<a name="Footnote_42" id="Footnote_42"></a><a href="#FNanchor_42">Anthropogenie</a> oder +<a name="Footnote_47" id="Footnote_47"></a><a href="#FNanchor_47">Entwicklungsgeschichte</a> des <a name="Footnote_51" id="Footnote_51"></a><a href="#FNanchor_51">Menschen</a>,' the +fourth edition of which appeared in 1891.</p> + +<p>It was a lucky coincidence that Haeckel +had just finished his preliminary academical +studies, was entirely at leisure, and undetermined +to which branch of natural science +he should devote his genius, when Darwin's +great work was given to the world. Haeckel +embraced the new doctrine fervently, and, +as Huxley was doing in England, he spread<span class="pagenum"><a name="Page_103" id="Page_103">[Pg 103]</a></span> +it and fought for it with ever-increasing +vigour in Germany.</p> + +<p>With marvellous vigour and quickness of +perception he applied the principles of Evolution +or the theory of descent to the whole +organic world, and not only opened entirely +new vistas for the study of morphology, +but also worked them out and fixed them. +He was the first to draw up pedigrees of +the various larger groups of animals and +plants, filling the gaps by fossils or with +hypothetical forms (the necessary existence +of which he arrived at by logical deductions); +and thus he reconstructed the first universal +pedigree, a gigantic ancestral tree, from the +simple unicellular Amœba to Man. Of course +these pedigrees were entirely provisional, as +he himself has over and over again avowed; +but they are, nevertheless, the ideal which all +systematists and morphologists working upon +the basis of Evolution have since been seeking +to establish.</p> + +<p>Naturally he was vigorously attacked, not<span class="pagenum"><a name="Page_104" id="Page_104">[Pg 104]</a></span> +only by anti-Darwinians, or rather anti-Evolutionists, +but also by many of those +who, having accepted the principle of transformism, +ought to have known better. +Perhaps they thought they did know better. +Imperfections or mistakes in details of the +grand attempt,—and these, naturally, were +many,—were singled out as samples of the +whole, which was ridiculed as the romance +of a dreamer.</p> + +<p>In the end, however, this hostility, narrow-minded +and unfair in many respects, has done +good to the cause. There has arisen an +ever-increasing school of workers in favour +of the new doctrine. Owing to renewed +research, criticism, corrections in all directions, +we now know considerably more about +natural classification (and this is pedigree) +than when Haeckel first opened out the +whole problem.</p> + +<p>Owing to his fearless mode of exposition, +regardless of the indignant wrath which the +new doctrine aroused in certain ecclesiastical<span class="pagenum"><a name="Page_105" id="Page_105">[Pg 105]</a></span> +quarters, Haeckel bore the brunt of almost +endless attacks, and had to write polemical +essays. The result has been that friend and +foe alike are now working on the lines which +he has laid down; most of the ideas which +he was the first to conceive, and to formulate +by inventing a scientific terminology for +them, have become important branches, or +even disciplines, of the science.</p> + +<p>Most morphologists of the younger generations +now take these terms for granted, without +remembering the name of their founder. +It is, therefore, perhaps not quite superfluous +to mention some of them:</p> + +<p><i>Phylum</i>, or stem, the sum total of all those +organisms which have probably descended +from one common lower form. He distinguished +eight such phyla—Protozoa, +Cœlenterata, Helminthes or Vermes, Tunicata, +Mollusca, Articulata, and Vertebrata. +The phyla are more or less analogous to +'super-classes,' large branches or 'circles,' or +principal groups of other zoologists.</p> + +<p><span class="pagenum"><a name="Page_106" id="Page_106">[Pg 106]</a></span></p> + +<p><a name="Footnote_43" id="Footnote_43"></a><a href="#FNanchor_43"><i>Phylogeny</i></a>, +the history of the <a name="Footnote_48" id="Footnote_48"></a><a href="#FNanchor_48">development</a> of the various <a name="Footnote_52" id="Footnote_52"></a><a href="#FNanchor_52">phyla</a>, classes, orders, +families,and species.</p> + +<p><i>Ontogeny</i>, the history or study of the +development of the individual, generally +called embryology. In reality the scope of +embryology is the ontogenetic study of the +various species, and this branch of developmental +study alone can be checked by direct, +'exact' observation, for the simple reason +that the individuals alone are entities, while +the species, genera, families, etc., are abstract +ideas.</p> + +<p>The <i>ontogenesis of any given living organism +is a short, condensed recapitulation of its +ancestral history or of its phylogenesis</i>. This +is Haeckel's 'fundamental biogenetic law.'</p> + +<p>A complete proof of the phylogeny of any +creature would be given by the preservation +of an unbroken series of all its fossil ancestors. +Such a series will in most cases, for obvious +reasons, always remain a desideratum. In a +few cases, however, the desideratum is nearly<span class="pagenum"><a name="Page_107" id="Page_107">[Pg 107]</a></span> +met: for example, the ancestral line of the +one-toed digitigrade horse from a four-or +five-toed plantigrade and still very generalized +Ungulate is approaching completion.</p> + +<p>Phylogenetic study has to rely upon other +help. This is afforded by comparative +anatomy and by the study of ontogeny. +If the latter were a faithful, unbroken recapitulation +of all the stages through which +the ancestors have passed, the whole matter +would be very simple; but we know for +certain that in the individual development +many stages are left out (or, rather, are +hurried through, and are so condensed by +short-cuts being taken that we cannot +observe them), while other features which +have been introduced obscure, and occasionally +modify beyond recognition, the original +course.</p> + +<p>Again, the sequence of the appearance +of the various organs is frequently upset +(<i>heterochronism</i>). Some organs are accelerated +in their development, while others,<span class="pagenum"><a name="Page_108" id="Page_108">[Pg 108]</a></span> +which we know to be phylogenetically older, +are retarded in making their reappearance in +the embryo.</p> + +<p>These disturbing or distorting newly introduced +features or factors show themselves +chiefly in connection with the embryonic conditions +of growth—for example, yolk-sac, +placenta, amnion. They all come within the +category of <i>cænogenesis</i>: they are cænogenetic, +while the true, undisturbed recapitulation is +<i>palingenetic</i>.</p> + +<p>Lastly, some features, so-called rudimentary +or vestigial organs, instead of disappearing, +are most tenacious in their recurrence, while +others of originally fundamental importance +scarcely leave recognisable traces, and are, so +to speak, only hinted at during the embryonic +growth of the creature we happen to study. +Hence arises the philosophical study of +'Dysteleology.'</p> + +<p>Among other terms invented by Haeckel, +and now in general use, are <i>Metamere</i>, +<i>Metamerism</i>, <i>Cœlom</i>, <i>Gonochorism</i>, <i>Gastrula</i>,<span class="pagenum"><a name="Page_109" id="Page_109">[Pg 109]</a></span> +<i>Metazoa</i>, <i>Gnathostomata</i>, <i>Acrania</i>, <i>Craniota</i>, +and <i>Amniota</i>.</p> + +<p>Hitherto we have dealt with his general +work only, a résumé of which he gave for +many years in a course of thirty lectures +before an audience composed of 'all sorts +and conditions of men.' Students of biology +and of medicine side by side with theologians, +incipient and ordained, jurists, political economists, +and philosophers, crowded his lecture-room +during the 'seventies to hear the master +explaining the 'natural history of creation' or +the mysteries of anthropogenesis. Another +course of eighty lectures during the winter +semester was, and still is, devoted to a +systematic treatment of zoology, while practical +classes are reserved for the more select.</p> + +<p>His winning personality and fascinating +eloquence, combined with a clear and concise +delivery, have gained the enthusiastic admiration +of many a student who went to the quiet +University town in order to learn with his +own ears and eyes.</p> + +<p><span class="pagenum"><a name="Page_110" id="Page_110">[Pg 110]</a></span></p> + +<p><i>List of Separate Publications by Professor +Haeckel.</i></p> + +<p>'Biologische Studien. I.: Studien ueber +die Moneren und andere Protisten.' Leipzig, +1870 (out of print). He was the first to +make observations on the natural history of +the Monera, living bits of protoplasm, devoid +even of a nucleus—<i>e.g.</i>, <i>Protogenes primordialis</i>, +<i>Protomyxa aurantiaca</i>.</p> + +<p>'Monographie der Radiolarien.' Berlin, +1862-88. With 171 plates.</p> + +<p>'Entwicklungsgeschichte der Siphonophoren.' +Utrecht, 1869.</p> + +<p>'Plankton-Studien. Vergleichende Untersuchungen +ueber die Bedeutung und +Zusammensetzung der pelagischen Fauna +und Flora.' Jena, 1880.</p> + +<p>'Metagenesis und Hypogenesis von +Aurelia aurita.' Jena, 1881.</p> + +<p>'Monographie der Geryoniden oder +Ruesselquallen.' Leipzig, 1865.</p> + +<p>'Generelle Morphologie der Organismen.' +2 vols. Berlin, 1866.</p> + +<p><span class="pagenum"><a name="Page_111" id="Page_111">[Pg 111]</a></span></p> + +<p>'Anthropogenie oder Entwicklungsgeschichte +des Menschen,' 1874; 4th edition, +1891.</p> + +<p>'Natuerliche Schoepfungs-Geschichte.' 2 +vols. Berlin, 1st edition, 1868; 9th edition, +1898. This work has been translated into +most European languages (the first edition in +English, under the title 'Natural History of +Creation' in 1873; the eighth in 1892).</p> + +<p>'Monographie der Kalkschwaemme.' 3 +vols. Berlin, 1872 (out of print). With the +subtitle, 'An Attempt to solve analytically +the Problem of the Origin of Species.' In +this work, illustrated by sixty plates, he +showed that the Calcispongia are individually +so yielding, so adaptive to external influences, +that it is practically impossible to break up +the whole group into anything like satisfactory +species or genera. According to +predilection, we can distinguish either 1 genus +with only 3 species, or 3, 21, 43 genera, with +21, 111, 181, or 289 species respectively.</p> + +<p>In this work, in 1872, Haeckel established<span class="pagenum"><a name="Page_112" id="Page_112">[Pg 112]</a></span> +the homology of the two primary layers, ecto- +and endoderm, throughout the Metazoa. +The attempt to do the same for the four +secondary layers, as made in the second part +of his 'Gastræa-theory,' failed. It caused +an enormous amount of research, hitherto +without a satisfactory solution of the problem.</p> + +<p>'Studien zur Gastræa-Theorie.' Jena, +1874. The transformation of the single +primitive egg-cell by cleavage into a globular +mass of cells (Morula)—which latter, becoming +hollow (and then known as the Blastula), +turns ultimately by invagination or by delamination +into the Gastrula—is a series of +processes which applies to all Metazoa. The +Gastrula is, therefore, the ancestral form of +the Metazoa; and the Gastræa-theory, +founded by Haeckel, throws light, on the one +hand, upon the mystery of the phyletic connection +of the various animal groups, while, +on the other hand, it connects the Metazoa, +or multicellular organisms, with the lowest +Protozoa. We come to this conclusion because<span class="pagenum"><a name="Page_113" id="Page_113">[Pg 113]</a></span> +the Gastrula arises from and passes +through stages which exist as independent, +permanent organisms among the Protozoa.</p> + +<p>Needless to say this Gastræa-theory has +been violently attacked in detail, with the +result that various modifications of the Gastrula, +until then undreamed of, have become +known.</p> + +<p>'Monographie der Medusen.' Jena, 1879-81. +With 72 coloured plates.</p> + +<p>'Reports on the Scientific Results of the +Voyage of H.M.S. <i>Challenger</i>.' With 230 +plates:</p> + +<blockquote> +<p>1. Deep-sea Medusæ. 1881.<br /> +2. Radiolaria. 1887.<br /> +3. Siphonophoræ. 1888.<br /> +4. Deep-sea Keratosa. 1889.<br /> +</p></blockquote> + +<p>A short holiday spent on the coasts of the +Red Sea produced the volume 'Arabische +Korallen' (Berlin, 1876); and a longer trip +to Ceylon has been described in 'Indische +Reisebriefe,' of which the third edition<span class="pagenum"><a name="Page_114" id="Page_114">[Pg 114]</a></span> +appeared in 1893. The English translation +(1883) is entitled 'A Visit to Ceylon.'</p> + +<p>'Monism as connecting Religion and +Science: the Confession of Faith of a Man +of Science.' 1894.</p> + +<p>Haeckels latest work is the 'Systematische +Phylogenie' (Berlin, 1896), three volumes +dealing with Protistæ and Plants, Invertebrata +and Vertebrata. They contain the author's +views on the natural system of the organic +world, both living and extinct. Notable in +the work are the many reconstructions of +ancestral forms which, provided Evolution is +true, must have existed—hypothetical until +they, or something like them, are found in a +fossil state. Everybody who works systematically, +and upon the basis of Evolution, +does, sometimes unconsciously, reconstruct +such links, although he may perhaps not see +the necessity, or have the courage to fix +his vision, by assigning to it all those attributes +or characters which are indicated by +deductions from comparative anatomy, palæontology, +and embryology.</p> + +<p><span class="pagenum"><a name="Page_115" id="Page_115">[Pg 115]</a></span></p> + +<hr class="chap"/> +<div class="chapter-beginning"/> +<h2>THEORY OF CELLS.</h2> + + +<p>The vegetable cell was discovered by +<i>Schleiden</i>, Professor of Botany at Jena, in +1838. Next year <i>Schwann</i> found the animal +cell.</p> + +<p>In 1844 <i>Koelliker</i> discovered that the egg +cell, by division and multiplication, becomes +an aggregation—a heap of new cells.</p> + +<p>In 1849 <i>Huxley</i> found the two primary +layers (observed long before by <i>Pander</i> and +<i>Baer</i> in the chick) also in certain Invertebrata, +the Medusæ; and he called these layers +'ectoderm' and 'endoderm' respectively.</p> + +<p>In 1851 <i>Remak</i>, in his 'Untersuchungen +über die Entwicklung der Thiere,' showed +the egg to be a simple cell, and that from it, +by repeated division or multiplication, arise<span class="pagenum"><a name="Page_116" id="Page_116">[Pg 116]</a></span> +the germinal layers, and that by differentiation +of the cells of these layers are formed +all the tissues of the body.</p> + +<p><i>Kowalevsky</i>, of St. Petersburg, found the +two primary germinal layers also in Worms, +Echinoderms, Articulata, and other animals.</p> + +<p><i>Haeckel</i>, in 1872, found the same in the +Sponges. He stated that these two germinal +layers occur in all animals, except in the +Protozoa; and that they are homologous, +or equivalent, in all the groups of animals, +from the Sponges up to Man. In 1873, in +his 'Gastræa-theorie,' he explained the +phylogenetic significance, and tried to show +the homology, of the four secondary germinal +layers.</p> + +<p><span class="pagenum"><a name="Page_117" id="Page_117">[Pg 117]</a></span></p> + +<hr class="chap"/> +<div class="chapter-beginning"/> +<h2>FACTORS OF EVOLUTION.</h2> + + +<p>An organism, as living matter, does not +stand in opposition to, or outside of, the rest +of the world. It is part of the world. It +receives matter from its surroundings, and +gives some back; therefore it is influenced +by its surroundings. It is acted upon, and +it reacts upon the latter, and if these change +(and they are nowhere and never strictly the +same) the organism also <i>varies</i>. It <i>adapts</i> +itself, and if it does not, or, rather, cannot, +do so, it dies, because it is unfit to live in the +world, or, rather, in those particular surroundings +and conditions in which it happens to be. +That organism which yields most easily, accommodates +itself most quickly, has the best +chance of existence—<i>survival of the fittest</i>.<span class="pagenum"><a name="Page_118" id="Page_118">[Pg 118]</a></span> +'Fitness' in this case does not mean fitness +to live, but rather a particular condition which +happens to fit into the new circumstances.</p> + +<p>Adaptation and variation are simultaneous: +they are fundamentally the same. If there +were no adaptability and no variability, +those simplest of organisms which we suppose +to have sprung into existence in the +pre-Cambrian period would long ago have +ceased to exist.</p> + +<p>It is the physiological momentum which +models the organism, and, by causing its +adaptations, has produced its organs by +change of function. Gegenbaur illustrates +this most important fundamental truth by +an excellent example. Suppose that, in an +absolutely simple organism, all the parts of +its exterior are under the same functional +conditions, so that each part of the surface +can take in food, and that this is digested, +assimilated, in the interior. There is, in +this condition, not yet any definite organ. +If this organism sinks to the bottom and<span class="pagenum"><a name="Page_119" id="Page_119">[Pg 119]</a></span> +becomes sessile, this part is excluded from +taking in nourishing matter, while the +opposite surface alone remains, or becomes +more, fit for this function. Thus, a simple +variation and adaptation has been produced, +and if the same organism continues in this +position, its bottom cells will estrange themselves +from their original function, while +those on the top will convey the food into +the interior, where a cavity will be formed, +ultimately with a permanent opening, the +primitive gut and mouth, both very different +from the 'foot.'</p> + +<p>Thus, by adaptation and variation the +organism acquires new functions, organs, +features, and it gives up and eventually loses +others. Its offspring is like it. Like produces +like. This is the principle of <i>heredity</i>. +Adaptation, when going on generation after +generation on the same lines in the same +direction, becomes continuous, and has an +intensifying, <i>cumulative</i> effect. By always +weeding out from a flock of pigeons those birds<span class="pagenum"><a name="Page_120" id="Page_120">[Pg 120]</a></span> +which possess more dark feathers than the +rest, we ultimately produce an entirely white +race. We hurry on what Nature does slowly.</p> + +<p>The inheritance of acquired characters +becomes very obvious in the following +example: The Monera are the lowest living +organisms known; they consist of a mass of +protoplasm, and are still devoid of even a +nucleus. They multiply simply by division; +each half is like the other, and like the parent +(which by this process has ceased to exist), +except that each is smaller and has to grow. +A certain Moneron, <i>Protomyxa aurantiaca</i>, +is orange-coloured, and its offspring is from +the beginning of the same colour, and this +colour has been acquired by that kind of +Monera-like protoplasm which thereby has +become the species called Aurantiaca. We +have no reason for assuming that there +existed from the beginning of life not only +colourless, but also red, orange, and other +kinds of protoplasm. In these simplest of +organisms the whole process of heredity<span class="pagenum"><a name="Page_121" id="Page_121">[Pg 121]</a></span> +seems very obvious; but in the higher ones, +in those which propagate by eggs, the +problem is infinitely more complicated. It +is true that the egg is, strictly, nothing but a +small part of the parental organism, and we +know from everyday experience that this +single egg-cell has in it all the attributes and +characteristics of the parent; but these attributes +and characteristics make their appearance +successively, just as the egg cell of a +chick has neither wings nor feathers, not +even a backbone, but develops these organs +because its parents have them.</p> + +<p>The theory that acquired characters are +hereditary has often been vigorously attacked; +but the champions of the negative position +have not given us anything satisfactory +instead. They question, also, the principle +of adaptation as a factor in Evolution, and +substitute 'variation,' coupled with 'natural +selection.'</p> + +<p>They point to Darwin's argument: (1) It +is a fact that animals and plants produce a<span class="pagenum"><a name="Page_122" id="Page_122">[Pg 122]</a></span> +much greater number of young than in their +turn grow up to propagate the race; (2) no +two of the frequently many individuals of +the same breed are exactly alike, although +the differences may be hidden to our perception +(this is quite true, because no two +entities can live in absolutely the same place +and conditions); (3) through heredity the +offspring takes over the faculties and features +of the parents; (4) what decides which of +the many individuals (each one possessing +some aberration or variation) are to live and +to propagate the race?—obviously those +individual variations which happen to make +the lucky possessors most fit for the struggle +for life.</p> + +<p>So far, well; but the 'Neo-Darwinians' +imagine that 'adaptation' is not the cause, but +the result, the effect, of the formation of +species. According to them, the species are +neither adapted by, nor do they adapt themselves +to, their surroundings. Adaptation is to +them an accomplished fact, a condition which a<span class="pagenum"><a name="Page_123" id="Page_123">[Pg 123]</a></span> +species happens to be in because its particular +variation is the one which, to the exclusion +of others, suits or fits into its surroundings. +Such a view simply takes variation for +granted, and stipulates it as a something +<i>a priori</i>, without raising the further necessary +question, why there should be any +variations at all. Why, indeed, unless they +are caused by external influences? Haeckel +elucidated this by the conception of adaptation +as explained in the foregoing pages.</p> + +<p>These and kindred speculations have produced +some rather curious discussions, which +not infrequently end in conundrums. If we +speak of a case of adaptation as a condition, a +fact, we easily run the risk of getting into confusion +about cause and effect. For example: Is +the stag swift because he has long and slender +legs, or are his legs long because he is swift? +In reality, swiftness and length of legs are +cause and effect in one. His legs have been +so modified as to make him swift, because he +has put them continuously to whatever was<span class="pagenum"><a name="Page_124" id="Page_124">[Pg 124]</a></span> +his full speed, which in his thick-footed +ancestors was probably a very slow one. +The above question reads, therefore, more +sensibly as follows: Has the stag become +swift because his legs have become long and +slender, or have his legs become long and +slender because he has attained swiftness? +Now, we see that both halves of the double +question are practically the same and instantly +suggest the answer.</p> + +<p>A fundamental difference between artificial +machines and living organisms is that the +former are worn out by use, while the latter +not only repair the loss caused by use, but are +also stimulated to further increase. On the +other hand, organs which are not put into +function, or are not used, <i>degenerate</i>. The +various cells of the organ react upon external +stimuli by increased activity. Why this should +be so is another question—perhaps because +those which do not would soon be not fit to +survive. Each cell has a function; the more +specialized the more intense it is. Every<span class="pagenum"><a name="Page_125" id="Page_125">[Pg 125]</a></span> +external stimulus, every contact with the +outer surroundings, is an insult, necessarily +of detrimental effect, as it disturbs the equilibrium +of the cell body. It must, therefore, +be of advantage to the cells' well-being to +return as soon as possible to the <i>status quo +ante</i>, and this can only be done by increased +activity.</p> + +<p>In the present state of our knowledge, +we can approach only the simplest cases of +acquisition of characteristics. Mostly they +are so complicated, subject to so many unthought-of +conditions, that we do not know +from which end to approach the problem. +Frequently the supposed use of certain +obvious features is the merest guesswork. +This applies especially to features to which +we are not accustomed (although wrongly +so) to assign a function—for example, coloration. +A green tree-frog will with predilection +rest on green leaves. The advantages +of concealment are obvious, and in this case +he 'adapts himself' to the surroundings by<span class="pagenum"><a name="Page_126" id="Page_126">[Pg 126]</a></span> +making for green localities: if he did not +he would be eaten up sooner than his more +circumspect comrades. But this making for, +and sitting in, the green has not <i>necessarily</i> +made him of that colour. Extreme advocates +of one view would argue as follows: +Once upon a time there were among the +offspring of ancestral tree-frogs some which, +among other colours, exhibited green, not +much, perhaps not even perceptible to our +eyes. The occurrence of this colour, according +to them, was spontaneous, a freak—as if +in reality there were anything spontaneous +in the sense of being causeless. The +descendants of these more greenish creatures, +provided they did not pair with frogs of the +ordinary set, became still greener (by accumulative +inheritance), and so on, until the green +was pronounced sufficient to be of advantage +when competition could set in.</p> + +<p>With this view there is always the difficulty +of understanding how the initial very +small changes can be useful, unless we have<span class="pagenum"><a name="Page_127" id="Page_127">[Pg 127]</a></span> +to deal with extremely simple organisms. Is +it likely in the case of our frogs that an +almost imperceptible variation in colour makes +them more fit to live? We have to assume +that 'luck' or chance kept them for generations +out of harm's reach, until the accumulation +of green, hitherto quite ineffective, +neither harmful nor useful, became strong +enough to be effective. Such cases undoubtedly +happen.</p> + +<p>But we can also argue out this problem +in a somewhat different way, which goes +nearer to the root of the whole process. The +original slight, imperceptible change in pigmentation +is not a spontaneous freak; it was +caused by the direct influence of the surroundings +in which the particular frogs +happened to live, be this factor light or +temperature or food. Thus it stands to +reason that the offspring, living under similar +conditions, will be acted upon in the same +way. That factor which has added green to +the parents will add green to the children,<span class="pagenum"><a name="Page_128" id="Page_128">[Pg 128]</a></span> +until by accumulative inheritance a more +decidedly green race is produced.</p> + +<p>The offspring of green plants do not +become green when grown in the dark; the +young plants inherit not the green, but the +capacity of becoming green when acted upon +by sunlight. This as an instance of direct +influence of the surroundings on a substance +(chlorophyll), which has not yet performed a +function. But the kittens of a pair of black +cats produce black hair before they are born, +and we have no reason to doubt that the +black pigment in their tegumentary structures +is ultimately referable to the action of the +sunlight. In many instances creatures living +for generations in darkness become white, +pigmentless, and they regain it when exposed +to light. For example, the white, colourless +Proteus from the caves of Adelsberg becomes +clouded grey, and ultimately jet black, when +kept in a tank whence light is not strictly +excluded.</p> + +<p>Blindness is a very general characteristic<span class="pagenum"><a name="Page_129" id="Page_129">[Pg 129]</a></span> +of creatures which dwell in darkness. There +are all stages between total blindness and +weak eyes. Now, do these blind creatures +live in darkness because they are blind, or +have they become first weak-eyed and then +blind because of the continuous disuse of +their eyes? The former explanation has +actually been suggested! Individuals not +smitten, but spontaneously, as a freak, born +with sore eyes, have crept into the darkness +for relief and have produced a blind race! +To carry such a notion to the bitter end leads +to absurdities. Anyhow, it is not understandable +where the benefit of losing the +eyesight arises. It can be explained only +by continued disuse: witness <i>Spalax typhlus</i>, +the blind mole, and, above all, the Endoparasites.</p> + +<p>Let us now take an example to explain the +influence of a tangible external stimulus. +Repeated pressure produces callosities. +Although they are not exactly beneficial +in the shape of corns on our toes, they are<span class="pagenum"><a name="Page_130" id="Page_130">[Pg 130]</a></span> +so on our hands. At any rate, the morphologist +can trace the development of the +footpads, nails, hoofs, and horns, step by +step from small beginnings. The cells of +the Malpighian stratum, of the inner, active +portion of our epidermis, are excited to extra +activity, and by continually producing more +horn cells than peel off the surface of the +skin in the normal process of wear and tear +cause the formation of the pad. It need +scarcely be mentioned that hypertrophic +growths are not necessarily useful; they are +often harmful, and in that case pathological.</p> + +<p>Lastly, a few words about the very difficult +question of <i>teleology</i>. In trying to explain +Evolution in a mechanical—sometimes called +monistic, but in reality natural—way, we +exclude anything like a set purpose, a goal, +or ideal, a final condition which the organism +strives to attain. Unknown, however, to +many morphologists, especially embryologists, +their writings are full of this teleological +notion. Indeed, there are many cases<span class="pagenum"><a name="Page_131" id="Page_131">[Pg 131]</a></span> +in which an organism becomes changed, and +quickly, too, in a way which cannot but be +called reasonable. It starts modifications, be +they outgrowths, alterations in shape or colour, +or the making good of injuries received, +which by 'short-cuts' produce the only +advantageous result that can reasonably +satisfy the new requirement or altered circumstances.</p> + +<p>Trees growing in precarious positions, +after part of the supporting rock has slipped +away, throw out new roots, and rearrange some +of the old ones in the only way which could +save the tree. In animals which have lost part +of a limb the wound closes up, and what is left +is turned into a serviceable stump—for +example, in water-tortoises (creatures in which +reproduction of lost limbs does not happen). +In frogs and newts the lost part is reproduced, +not correctly, but in a good semblance. +Tortoises which have had their shell smashed +can throw off an astonishingly large portion +and renew the bone as well as the over<span class="pagenum"><a name="Page_132" id="Page_132">[Pg 132]</a></span>lapping +scutes; but this mending is not neatly +done. It serves the requirement, but it is +patchwork; the new shell is such as no +tortoise ever possessed before.</p> + +<p>Mammals transported into colder countries, +or subjected to continued exposure, grow a +thicker coat; and the same kind of tree +which in a sheltered valley is tall, large-leaved, +and soft-wooded, assumes a very +different aspect, although perhaps growing +into a healthy specimen, when planted on a +wind-exposed hill.</p> + +<p>There is no room, or, rather, no time, to +apply to these cases the principle of many +variations or the long-continued accumulation +of infinitely small changes. The thing is to +be done quickly, or not at all. Nor can we +explain the mending of a wound, which +implies an activity of countless cells, simply +as a case of, or similar to, the reproduction +of a lost part; against such an +explanation militates the almost absolute +unlikelihood of that precise injury having<span class="pagenum"><a name="Page_133" id="Page_133">[Pg 133]</a></span> +happened before to any of the creature's +ancestors.</p> + +<p>Still, I think we are brought near the solution +of the mystery by such considerations. +We see no difficulty in the regeneration of a +few cells, or in the making good of the disturbance +suffered by one of the most simple +organisms; but we become suspicious when +we see that countless cells, not of one kind, +but of the most varied tissues and parts of +the body, make common cause in remedying +a defect in a serviceable way.</p> + +<p>We must assume that since the beginning +of life organisms have been subjected to +countless insults. We can scarcely speak of +a wound in an Amæba; but these insults +have always been made good, and whenever +this was not the case, that particular organism +came to an end. As these organisms developed +into more complicated ones, the +possible insults became more serious, more +complicated; and the organisms took adaptive +measures so as to be superior to them. This<span class="pagenum"><a name="Page_134" id="Page_134">[Pg 134]</a></span> +action, I have no hesitation in declaring, +became by heredity a habit. The whole +creature became so thoroughly 'imbued' (for +want of a better word) with the finding of +ways and means for meeting sudden, serious +conditions, that it now acts directly, and +produces by a short-cut, with the least amount +of time and with the smallest possible waste +of material, that which meets the occasion, +thereby saving the life of the individual and +that of the race. This we cannot but call +reasonable and to the purpose, although it is +all carried out by <i>causæ efficientes</i> without +there being any <i>causæ finales</i>.</p> + +<p><span class="pagenum"><a name="Page_135" id="Page_135">[Pg 135]</a></span></p> + +<hr class="chap"/> +<div class="chapter-beginning"/> +<h2>GEOLOGICAL TIME AND EVOLUTION.</h2> + + +<p>One million years is a stretch of time beyond +our conception. We can arrive at a more or +less adequate understanding of what a million +individuals or concrete things means. Several +Continental nations can put more than a +million men into the field. We can gaze at +a building which contains as many bricks; +and we know that our own body is composed +of millions of millions of cells. No +such help applies to time, because that itself +is an entirely relative, abstract conception. +We can imagine what one hundred years are +like—a span of time seemingly short to the +hale and hearty octogenarian, enormous to +the child, totally inapplicable to certain<span class="pagenum"><a name="Page_136" id="Page_136">[Pg 136]</a></span> +animals whose whole life is crowded into one +single day.</p> + +<p>Astronomers have long ceased to reckon +distances by miles or any other understandable +unit. They express the distances +between us and the stars and nebulæ by +'years of light.' Try to imagine a unit of +length equal to that which is passed through +by light (186,000 miles per second) in one +year. Not so very long ago the enormous +distances resulting from astronomical calculations +were looked upon as the most serious +objection to the correctness of the astronomers' +views as to the distances which separate our +globe from the nearest fixed stars. We have +not yet accustomed ourselves to reckoning +time by some similar broadly-conceived +standard—say æons of so many thousand +years each.</p> + +<p>Unfortunately, we possess no data whatever +for calculating the age of the successive +geological strata. Thanks to Lyell, the +theory of violent universal cataclysms has<span class="pagenum"><a name="Page_137" id="Page_137">[Pg 137]</a></span> +been done away with. It is more probable +that the same agencies have acted which are +now changing the aspect of the globe; and +these changes are slow, as far as we know +them—at least, as far as the formation of +sedimentary strata is concerned, and these +alone we have to deal with. Various calculations +have been made, based upon the +denudation of the mountains, the filling up of +the valleys by the débris, the formation of +deltas, etc. The results give enormous +stretches of time, but all of them unsatisfactory, +because the methods are so very local in +their application.</p> + +<p>The least objectionable attempt is that +which, based upon astronomical calculations, +tried to fix the height of the last Glacial +epoch<a name="FNanchor_27_27" id="FNanchor_27_27"></a><a href="#Footnote_27_27" class="fnanchor">[27]</a> at about 200,000 years ago, and +asserted that since its beginning in the +Pliocene epoch as many as 270,000 years +have elapsed. The duration of the whole<span class="pagenum"><a name="Page_138" id="Page_138">[Pg 138]</a></span> +Tertiary period has by the same authorities +been fixed approximately at 3,000,000 to +4,000,000 years. Beyond this we cannot venture +without the wildest speculation; but we +know to a certain extent the thickness of the +various sedimentary strata, which amount in +all to from 100,000 to 175,000 feet—on the +average perhaps 130,000 feet, or about twenty +miles.</p> + +<p>Unless we prefer giving up all attempt +at calculation as absolutely hopeless, and +thus resign the whole problem, we must at +least try to arrive at some results, and then +see if these cannot reasonably be made use of.</p> + +<p>Neither geologist nor physicist, and no +zoologist, would accept the suggestion that +these 130,000 feet of stratified rocks have +been deposited within only as many years, +although the average rate of deposit would +in that case be not more than 1 foot per +year. On the other hand, an indignant protest +is raised against the assumption of +1,000,000,000 years.</p> + +<p><span class="pagenum"><a name="Page_139" id="Page_139">[Pg 139]</a></span></p> + +<p>Lord Kelvin<a name="FNanchor_28_28" id="FNanchor_28_28"></a><a href="#Footnote_28_28" class="fnanchor">[28]</a> has come to the conclusion +(from data which various other authorities +regard as very unsatisfactory) that not +much more than 100,000,000 years can have +elapsed since the molten globe acquired a +consolidated crust. Further time must have +passed before the surface had become stable +and cool enough to allow the temperature of +the collecting oceans to fall below boiling-point, +and it is obvious that life cannot +possibly have begun until after this had +happened.</p> + +<p>Wallace, in his 'Island Life,' by making +use of Professor A. Geikie's results as to the +rate of denudation of matter by rivers from +the area of their basins, and estimating the +average rate of deposition, concludes that +'the time required to produce this thickness +of rock [Professor Haughton's maximum of +177,000 feet] at the present rate of denudation +and deposition is only 28,000,000 years.'<span class="pagenum"><a name="Page_140" id="Page_140">[Pg 140]</a></span> +Our lower assumption of 130,000 feet thickness +would give only 20,000,000 years—a +rate of 1 foot in 154 years.</p> + +<p>Again, if we prefer round numbers to start +with, we have only to assume that the age of +the whole Tertiary period, with its 3,000 feet +thickness, is 3,000,000 years (<i>i.e.</i>, 1,000 feet +in 1,000,000 years, or 1 foot in 1,000 years, +surely an excessively slow rate); then +130,000,000 years would bring us to the +bottom of the Laurentian or pre-Cambrian +deposits. Of course, it is a pure assumption +that the same rate of destruction and sedimentation +applies to the whole of the strata; +but we know nothing to the contrary, especially +if we consider the average periods, the +quick periods of extra activity, taken with the +slow periods or those of standstill.</p> + +<p>Dana estimated the length of the whole +Tertiary period at one-fifteenth of the Mesozoic +and Palæozoic combined. If we take +the duration of the Tertiary period, as before, +as 3,000,000 to 4,000,000 years, the total<span class="pagenum"><a name="Page_141" id="Page_141">[Pg 141]</a></span> +will amount to from 45,000,000 to 60,000,000 +years.</p> + +<p>Lastly, Walcott<a name="FNanchor_29_29" id="FNanchor_29_29"></a><a href="#Footnote_29_29" class="fnanchor">[29]</a> has estimated the duration +of the Palæozoic, Mesozoic, and Cænozoic +or Tertiary epochs at about 17,000,000, +7,000,000 and 3,000,000 years respectively, +giving 27,700,000 years from the beginning +of the Cambrian; and Williams<a name="FNanchor_30_30" id="FNanchor_30_30"></a><a href="#Footnote_30_30" class="fnanchor">[30]</a> has calculated +the relative duration of the smaller +epochs. See the table on p. 149.</p> + +<p>The results of all these calculations fall +surprisingly well within the limits of Lord +Kelvin's allowance. Of course they are +based upon assumptions, but none of them +is inherently unreasonable; and it was my +purpose to draw attention to the surprising +coincidence in the closeness of these results, +perhaps too good to be true. Such calculations +are considered close enough if they +range within a few multiples of each other.</p> + +<p><span class="pagenum"><a name="Page_142" id="Page_142">[Pg 142]</a></span></p> +<p>Zoologists have fallen into the habit of +requiring enormous lengths of time for the +evolution of the animal kingdom. We know +that Evolution is at best a slow process, and +the conception of the changes necessary to +evolve man from monkey-like creatures, these +from the lowest imaginary mammals, these +from some reptilian stock, thence descending +to Dipnoan fish-like creatures, and so on +back into Invertebrata, down to the simple +Monera—this conception is indeed gigantic. +Innumerable, almost endless, slow changes +require seemingly unlimited time, and as time +is endless, why not draw upon it <i>ad libitum</i>?</p> + +<p>Huxley pointed out that it took nearly the +whole of the Tertiary epoch to produce the +horse out of the four-toed Eohippos, and +that, if we apply this rate to the rest of +its pedigree, enormous times would be required. +This is, however, a very misleading +statement, which necessitates considerable +reduction, in conformity with our increased +palæontological knowledge. Animals of the<span class="pagenum"><a name="Page_143" id="Page_143">[Pg 143]</a></span> +genus Equus—namely, Ungulata, with one +toe, and with a certain tooth pattern—from +the Upper Miocene of India are now known. +Moreover, it is not simply a question of the +gradual loss of the side-toes. The change +from the fox-sized little Eohippos and Hyracotherium, +so far as skull, teeth, vertebral +column, and limbs are concerned (about the +soft parts we know next to nothing), is a +very great one indeed.</p> + +<p>Elephants and mammoths seem to have +developed very rapidly. None are known +from Eocene strata; but towards the end +of the Miocene they had spread over Asia, +Europe, and North America, and that in +great numbers. The Eocene Amblypoda +are still so different that we hesitate to connect +them ancestrally with the elephants.</p> + +<p>The Pinnipedia (seals and walruses) are +strongly modified fissiped Carnivora, and have +existed since at least the Upper Miocene; +the transformation must have been accomplished +within the Miocene period.</p> + +<p><span class="pagenum"><a name="Page_144" id="Page_144">[Pg 144]</a></span></p> + +<p>We cannot shut our eyes to the fact that +various groups have from the time of their +first appearance burst out into an exuberant +growth of modifications in form, size, and +numbers, into all possible—and one might +almost say impossible—shapes; and they +have done this within comparatively short +periods, after which they have died out not +less rapidly. It seems almost as if these go-ahead +creatures had, by accepting every +possible modification and carrying the same +to the extreme, too quickly exhausted their +plasticity—which, after all, must have limits—thereby +becoming unable to meet successfully +the requirements of further changes in their +surroundings. The slowly developing groups, +keeping within main lines of Evolution, and +not being tempted into aberrant side-issues, +had, after all, a much better chance of onward +evolution.</p> + +<p>A good example of the former are the +Dinosaurs. We do not know their ancestors; +but we have here to deal only with their<span class="pagenum"><a name="Page_145" id="Page_145">[Pg 145]</a></span> +range of transformation. The oldest known +forms occur in the Upper Trias; they attain +their most stupendous development in the +Upper Jurassic and in the Wealden; and +they have died out with the Cretaceous epoch. +But already some of their earliest forms had +assumed bipedal gait, and the Oolitic Compsognathus +had developed almost bird-like hind-limbs.</p> + +<p>On the other hand, there are many +instances of extremely slow development—facts +which raise the difficult question of +'persistent types.' Are these due to a state of +perfection which cannot be improved upon? +Or are they due to a kind of morphological +consolidation (not necessarily specialization) +which can no longer yield easily, so that therefore +through changes in their surroundings +they may come to an end sooner than more +plastic groups?</p> + +<p>Struthio, the ostrich; Orycteropus, the +Cape ant-eater; Tapirus, and many others, +existed in the Miocene age practically as<span class="pagenum"><a name="Page_146" id="Page_146">[Pg 146]</a></span> +they are now; but pre-Pliocene dolphins, +cats, monkeys, stags, all belong to closely-allied +and well-defined 'genera,' but different +from the living forms.</p> + +<p>Alligators and crocodiles are known from +the Upper Chalk; Tomistoma since the +Miocene; Gavialis since the Pliocene.</p> + +<p>The oldest surviving reptile is Sphenodon, +the Hatteria of New Zealand, a fair representative +of what generalized reptiles of the +later Triassic period seem to have been like; +and to the same period belongs Ceratodus, +the Australian mud-fish, hitherto the oldest +known surviving genus of a very ancient and +low type so far as Vertebrata are concerned.</p> + +<p>Now let us see if the above estimates of +geological time are so utterly inapplicable to +animal evolution. On purpose we take one +of the lowest estimates, about 28,000,000 +years, and apportion them equally to the +various strata or epochs.</p> + +<p>The original owner of the famous Trinil +skull, a <i>Pithecanthropus erectus</i>, lived,<span class="pagenum"><a name="Page_147" id="Page_147">[Pg 147]</a></span> +according to some, in the Late Pliocene, +according to others in the Early Plistocene, +period—that is to say, somewhere about +the beginning of our last Glacial epoch, +some 270,000 years ago. Assuming that +he and his like reached puberty at sixteen +to twenty years of age, about 17,000 generations +would lie between him and ourselves, +or, to put it more forcibly, between +him and the lowest living human races—say +the Ceylonese Veddahs. Only 250 generations, +at twenty years, carry us back to +3000 <span class="smcap">B.C.</span> (<i>i.e.</i>, beyond the ken of history); and +if it be objected that the differences between +the oldest inhabitants of Egypt, the Naquada, +and the present Fellahin are very slight, +we are welcome to multiply these differences +sixty or seventy fold, in order to arrive at the +Pithecanthropus level. But these Naquada +had no metal implements, and there cannot be +the slightest doubt that the development of +the human race went on by leaps and bounds +after certain discoveries had been made—to<span class="pagenum"><a name="Page_148" id="Page_148">[Pg 148]</a></span> +wit, the use of implements and that of fire. +That creature which first took up a stone or +a branch and wielded it thereby got such an +enormous advantage over his fellow-creatures +that his mental and bodily development went +on apace. The same applies to the improvement +of speech. We assume the single, +monophyletic origin of mankind at one place, +in one district; and the differences between +some of the races of man are great enough +to constitute what we might call species. +Compare the Venus of Milo, that noble expression +of the ancient Greeks' notion of +female beauty, with the 'products of art' of +the Veddahs or the dwarfs of Central Africa, +or think of the beau-idéal which a Michael +Angelo could possibly have evolved if he had +never seen any but such people.</p> + +<p><span class="pagenum"><a name="Page_149" id="Page_149">[Pg 149]</a></span></p> + +<div style="line-height:90%"> +<table id="tae" summary="time" cellpadding="1" cellspacing="0" rules="cols" frame="box"> +<tr style="border:1px solid black;"> + <td class="tdc">I.</td> + <td class="tdc">II.</td> + <td class="tdc" >III.</td> + <td class="tdc" >IV.</td> + <td class="tdc" >V.</td> + <td class="tdc" >VII.</td> + <td class="tdc">VII.</td> +</tr> +<tr> + <td class="tdl">Recent</td> + <td class="tdl">}</td> + <td class="tdl" ></td> + <td class="tdl" ></td> + <td class="tdl" >Adam and Eve</td> + <td class="tdr" ></td> + <td class="tdr">250</td> +</tr> +<tr> + <td class="tdl"> Plistocene</td> + <td class="tdl">} 5</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" >Man, contemp-</td> + <td class="tdr" ></td> + <td class="tdr">3,500</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >} 270,000</td> + <td class="tdl" > orary with Reindeer</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" > in France</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Pliocene -</td> + <td class="tdl">}</td> + <td class="tdl" >} 3,000,000</td> + <td class="tdl" ></td> + <td class="tdl" >Pithecanthropus</td> + <td class="tdr" >16</td> + <td class="tdr">17.000</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >} 600,000</td> + <td class="tdl" > erectus</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Miocene -</td> + <td class="tdl">}10</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdl" >Anthropoid</td> + <td class="tdr" >10</td> + <td class="tdr">60,000</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">}</td> + <td class="tdl">}</td> + <td class="tdl" >} 2,100,000</td> + <td class="tdl" > Apes</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Eocene -</td> + <td class="tdl">}</td> + <td class="tdl" ></td> + <td class="tdl" >}</td> + <td class="tdl" >Lemurs</td> + <td class="tdr" >5</td> + <td class="tdr">420,000</td> +</tr> +<tr> + <td class="tdl">Cretaceous -</td> + <td class="tdl"> 10</td> + <td class="tdl" >}</td> + <td class="tdl" > 3,600,000</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Jurassic -</td> + <td class="tdl"> 5</td> + <td class="tdl" >}</td> + <td class="tdl" > 1,800,000</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Rhætic -</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" >Prototheria, or</td> + <td class="tdr" >3</td> + <td class="tdr"> 1,800,000</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" > first Mammalia</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">}</td> + <td class="tdl" >} 7,200,000</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Keuper -</td> + <td class="tdl">} 5</td> + <td class="tdl" >}</td> + <td class="tdl" >}1,800,000</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Muschelkalk -</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">New Red</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" >Theomorpha</td> + <td class="tdr" >4</td> + <td class="tdr">425,000</td> +</tr> +<tr> + <td class="tdl"> Sandstone </td> + <td class="tdl"></td> + <td class="tdl" ></td> + <td class="tdl" ></td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Magnesian</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"> Limestone</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Lower Red</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" >Proreptilia</td> + <td class="tdr" >4</td> + <td class="tdr">250,000</td> +</tr> +<tr> + <td class="tdl"> Sandstone</td> + <td class="tdl">}15</td> + <td class="tdl" >}</td> + <td class="tdl" >}4,000,000</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Coal-measures</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" >Eotetrapoda</td> + <td class="tdr" >4</td> + <td class="tdr">500,000</td> +</tr> +<tr> + <td class="tdl">Mountain</td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl"> Limestone</td> + <td class="tdl">}</td> + <td class="tdl" >}17,500,000</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> + +<tr> + <td class="tdl">Devonian -</td> + <td class="tdl"> 15</td> + <td class="tdl" >}</td> + <td class="tdl" >4,000,000</td> + <td class="tdl" >Dipnoi and</td> + <td class="tdr" >5</td> + <td class="tdr">1,000,000</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl"></td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdl" > Crossopterygii</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Silurian -</td> + <td class="tdl"> 10</td> + <td class="tdl" >}</td> + <td class="tdl" >2,700,000</td> + <td class="tdl" >First fishlike</td> + <td class="tdr" >3</td> + <td class="tdr">900,000</td> +</tr> +<tr> + <td class="tdl"></td> + <td class="tdl">}</td> + <td class="tdl" >}</td> + <td class="tdl" ></td> + <td class="tdl" > creatures</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Ordovician -</td> + <td class="tdl"> 10</td> + <td class="tdl" >}</td> + <td class="tdl" >2,700,000</td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Cambrian -</td> + <td class="tdl"> 15</td> + <td class="tdl" >}</td> + <td class="tdl" > 4,000,000</td> + <td class="tdl" >Sum total of</td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +<tr> + <td class="tdl">Laurentian -</td> + <td class="tdl"></td> + <td class="tdl" ></td> + <td class="tdl" ></td> + <td class="tdl" > generations</td> + <td class="tdr" ></td> + <td class="tdr">————</td> +</tr> +<tr> + <td class="tdl">Archean or</td> + <td class="tdl"></td> + <td class="tdl" ></td> + <td class="tdl" ></td> + <td class="tdl" > (about)</td> + <td class="tdr" ></td> + <td class="tdr">5,375,000</td> +</tr> +<tr> + <td class="tdl"> Metamorphic</td> + <td class="tdl"></td> + <td class="tdl" ></td> + <td class="tdl" ></td> + <td class="tdl" ></td> + <td class="tdr" ></td> + <td class="tdr"></td> +</tr> +</table> +</div> +<p><span class="pagenum"><a name="Page_150" id="Page_150">[Pg 150]</a></span></p> + +<p><span class="smcap">Explanation of the Table on p. 149.</span></p> + +<blockquote> + +<p>Column I. contains the names of the successive sedimentary +strata.</p> + +<p> " II. contains the percentage of the duration of the +various epochs, according to <i>Williams</i>, the +time from the Cambrian until recent times +being taken as 100.</p> + +<p> " III. gives the estimated duration in years of the +Palæozoic, Mesozoic, and Cænozoic periods, +according to <i>Walcott</i>.</p> + +<p> " IV. gives in years the duration of the various +smaller epochs, as computed from Walcott and +Williams' statements.</p> + +<p> " V. Representatives of stages of the ancestral line of +man. The names stand in the level of the +stratum in which they have made their first +appearance.</p> + +<p> " VI. contains the number of years which, in the present +calculation, have been assumed necessary for +the animal to reach puberty.</p> + +<p> " VII. contains the number of generations which can +have elapsed from stage to stage. For example, +60,000 generations separate the earliest known +anthropoid apes from Pithecanthropus.</p> +</blockquote> + +<p>Let us follow the descent of man further +back. The next stage, reckoning backwards, +is that from Pithecanthropus to <i>bonâ-fide</i> +anthropoid apes. They are represented in +the Miocene by various genera—<i>e.g.</i>, Pliopithecus +and Dryopithecus. According to +Croll and Wallace, 850,000 years ago carry us<span class="pagenum"><a name="Page_151" id="Page_151">[Pg 151]</a></span> +into the Miocene epoch. Assuming that +these apes lived about 600,000 years before +Pithecanthropus, namely, in the later half of +the Miocene, and taking puberty at ten years +of age, a high estimate, we get not less than +60,000 generations.</p> + +<p>2. From Apes back to lowest Lemurs in +the lowest Eocene. The date of Eocene +being fixed at 3,000,000, we have about +2,100,000 years for this stage; assuming as +much as five years for puberty, this results in +420,000 generations.</p> + +<p>3. From Lemures to Prototheria. The +earliest known mammalian remains come +from the Rhætic, or top formation of the +Triassic epoch; allowing for the Rhætic +only 100,000 years, we have to add the +whole of the Jurassic and Cretaceous, in all +about 5,500,000 years. Assuming three +years for a generation, we get 1,800,000 +generations.</p> + +<p>4. From Prototheria to something like the +Theromorpha at the bottom of the Triassic<span class="pagenum"><a name="Page_152" id="Page_152">[Pg 152]</a></span> +strata. A duration of 1,700,000 years divided +by four gives 425,000 generations.</p> + +<p>5. From Theromorpha to Proreptilia, +represented by Eryops and Cricotus from +the Lower Permian of Texas. Allowing +1,000,000 years, each generation at four +years, we obtain 250,000 generations.</p> + +<p>6. From Proreptilia to Eotetrapoda, the +first terrestrial Vertebrata, represented by +something like the Stegocephali, the earliest +of which are known from the Coal-measures. +Assuming them to have come into existence +at the bottom of the Coal-measures, for the +duration of which we may guess 2,000,000 +years, we get, with four years' allowance for +puberty, 500,000 generations.</p> + +<p>7. From Eotetrapoda to a not yet separated +or differentiated group of Crossopterygian +and Dipnoan fishes, both of which +are known from Devonian strata. The +duration of the latter has been computed at +4,000,000 years, which, with 1,000,000 for +the Mountain Limestone formation, gives us<span class="pagenum"><a name="Page_153" id="Page_153">[Pg 153]</a></span> +5,000,000 for this stage. Assuming, for the +sake of round numbers, as much as five +years for a generation, we get 1,000,000 +generations.</p> + +<p>8. Earliest stage, down to the first fish-like +creatures. Teeth and spines indicating the +existence of fishes are known from the Upper +Silurian. By carrying the earliest fishes down +to the bottom of the Silurian, with 2,700,000 +years' duration, and allowing three years for +attaining puberty, the calculation results in +900,000 generations.</p> + +<p>Further back we cannot go. We do not +know of any Vertebrate remains from the +Ordovician and Cambrian, which together +represent 6,700,000 years, enough for at least +half as many generations of Prochordate +creatures. The pre-Cambrian or Laurentian +epoch lies quite beyond the reach of calculation, +nor have we any trustworthy fossil +remains of living matter from these strata, to +which, however, Haeckel and others refer the +first beginnings of life.</p> + +<p><span class="pagenum"><a name="Page_154" id="Page_154">[Pg 154]</a></span></p> + +<p>All the above calculations are, of course, +only approximate. What we do know is +the existence of representatives of the stages, +our proofs being the fossils; but when we refer +the origin of the Eotetrapoda, for example, to +the bottom and not somewhere to the middle +of the Coal-measures, we are guessing +merely. Alterations in the levels assumed +for the various stage-representatives will, of +course, alter the result of the number of +generations; but the leading idea, as a +whole, is not thereby upset. The fact +remains that in the Upper Silurian we have +fishes; from the Coal-measures onwards, fishes +and Amphibia; since the Permian, fishes, +Amphibia, and reptiles; since the end of the +Trias these three classes and the Mammalia; +and lastly, at least since the Plistocene, man +himself. If Evolution is true at all, the +transformation from early fish-like creatures +to man has come about within these epochs. +Being able to assign a time of duration to +each of them, with an approximate total of<span class="pagenum"><a name="Page_155" id="Page_155">[Pg 155]</a></span> +21,000,000 years, we are also able to put +the whole ancestral series to a test by expressing +each great stage in generations. The +result is very satisfactory. The whole enormous +stretch from the lowest fish-like creatures +to man has been resolved into more +than 5,000,000 successive generations, and +each of these means a little step forwards in +onward Evolution.</p> + +<p>Nothing is to be gained for the understanding +of our problem of Evolution if we +multiply this enormous number of generations +by ten or any other multiple. We +are not able to conceive changes so small +as those which necessarily have existed +between Pithecanthropus and man if the +whole striking difference is analysed into +17,000 steps. Every one of these stages in +the modifications of the muscles, the skeletal +framework, increase of brain, shortening of +the trunk, lengthening of the legs, improvement +of the hands, loss of the hairy coat, etc., +is truly microscopical, imperceptible, just as<span class="pagenum"><a name="Page_156" id="Page_156">[Pg 156]</a></span> +the Evolutionist imagines the whole process +to have been. Again, where is the difficulty +implied by the change from an air-breathing, +in many structural points half-amphibian, fish +into a primitive land-crawling four-footed +creature, if we are allowed to resolve the +transformation into 1,000,000 stages? So far +from there being any difficulty, rather does it +appear questionable if so many infinitely small +changes have been necessary to bring about +this result.</p> + +<p>One thousand years make apparently no +difference in the evolution of animals, nor +does one second change the aspect of the +hands on the face of a clock, nor did Julius +Cæsar's commission of scientific men appreciate +the error of about eleven minutes in +the length of the year beyond its real value; +but now the Russians are, owing to this +neglect, nearly two weeks behind the civilized +nations.</p> + + +<p class="center">THE END.<br /> + +<small>BILLING AND SONS, PRINTERS, GUILDFORD.</small></p> + +<p><span class="pagenum"><a name="Page_157" id="Page_157">[Pg 157]</a></span></p> +<hr class="chap"/> +<div class="chapter-beginning"/> +<p class="center">By PROFESSOR ERNST HAECKEL</p> + +<p class="center"><big>MONISM</big>;<br /> +<small>OR</small>,<br /> +The Confession of Faith of a Man of Science.</p> + +<p class="center"> Translated from the German by J. D. F. GILCHRIST.</p> + +<p class="center"><i>Crown 8vo., cloth. Price 1s. 6d. net.</i> +</p> + +<p>'We may readily admit that Professor Haeckel has stated his case +with the clearness and courage which we should expect of him, and +that his lecture may be regarded as a fair and authoritative statement +of the views now held by a large number of scientifically educated +people.'—<i>Times.</i></p> + +<p>'The Monism, which is the substance of his faith, is thus defined by +him: "Our conviction that there lives one spirit in all things, and that +the whole cognizable world is constituted, and has been developed, in +accordance with one common fundamental law." As the confession of +a distinguished man of science, this little work deserves to be read.'—<i>North +British Daily Mail.</i></p> + +<p>'This "Confession of Faith" was delivered by the great German +scientist, its author, as an extemporaneous address at Altenburg rather +more than two years ago. There are, no doubt, a large number of +English readers who will welcome a translation, for this "connecting of +religion and science" has long troubled many earnest students of +modern science.'—<i>Publisher's Circular.</i></p> + +<p>'This is a little book of great daring, an example of the wild speculative +flights of one of the very ablest and greatest of our contemporary +men of science.'—<i>Aberdeen Free Press.</i></p> + +<p>'The address, whatever we may think of its conclusions, is, however, +most interesting reading, and is admirably done into English by the +translator.'—<i>Literary World.</i></p> + + +<p class="center">LONDON: ADAM & CHARLES BLACK, SOHO SQUARE.</p> + +<p><span class="pagenum"><a name="Page_158" id="Page_158">[Pg 158]</a></span></p> +<hr class="tb"/> + +<p class="center"> <i>Demy 8vo., price 7s. 6d. net.</i></p> + +<p class="center"><big>SOURCES OF THE APOSTOLIC CANONS.</big></p> + +<p class="center"> <i>With a Treatise on the Origin of the Readership and other Lower Orders.</i></p> + +<p class="center"> By Professor ADOLF HARNACK.</p> + +<p class="center"> Translated by LEONARD A. WHEATLEY.</p> + +<p class="center"> <i>With an Introductory Essay on the Organization of the Early Church + and the Evolution of the Reader.</i></p> + +<p class="center"> By the Rev. <span class="smcap">John Owen</span>, Author of 'Evenings with the Skeptics.' +</p> + +<p>'Dr. Adolf Harnack is at the present time undoubtedly the leading liberal +authority in Germany on matters connected with early Christian history.'—<i>The +Times.</i></p> + +<p>'Those who are interested in early Church history know how to prize anything +from the pen of Prof. Harnack. They will not be disappointed with the present +paper, in which, with his accustomed learning and acute criticism, he annotates +and comments upon the fragments of primitive church law which partly form the +basis of the Apostolic Canons.'—<i>British Weekly.</i></p> + +<p>'The wide circulation of this volume would be of the happiest augury for a +more scientific and worthy conception of the organization of the primitive +Church.'—Dr. <span class="smcap">Marcus Dods</span> in <i>The Bookman</i>.</p> + + +<hr class="tb"/> +<p class="center"> <i>Crown 8vo., cloth, price 1s. 6d. net.</i></p> + +<p class="center"><big>CHRISTIANITY AND HISTORY.</big></p> + +<p class="center"> By ADOLF HARNACK.</p> + +<p class="center"> Translated, with the Author's sanction, by THOMAS BAILEY + SAUNDERS, with an Introductory Note. +</p> + +<p>'It is highly interesting and full of thought. The short introductory note with +which Mr. Saunders prefaces it is valuable for its information and excellent in its +tone.'—<i>Athenæum.</i></p> + +<p>'A singularly able exposition and defence of Christianity, as seen in the newer +light, by one of the most learned and acute "evangelical" critics of Germany. +The essay is a masterly one.'—<i>Glasgow Herald.</i></p> + +<p>' ... We hope the lecture will be widely read.'—<i>Primitive Methodist +Quarterly Review.</i></p> + +<p>'The lecture itself is weighty in its every word, and should be read and re-read +by those desiring to have in a nutshell the central positions of modern Christianity.'—<i>Christian +World.</i></p> + +<p class="center">LONDON: ADAM & CHARLES BLACK, SOHO SQUARE.</p> +<p><span class="pagenum"><a name="Page_159" id="Page_159">[Pg 159]</a></span></p> +<hr class="tb"/> + +<p class="center"> <i>Third Edition. Crown 8vo., cloth, price 5s.</i></p> + +<p class="center"><big>SKETCH OF THE HISTORY OF ISRAEL AND JUDAH.</big></p> + +<p class="center"> By J. WELLHAUSEN,<br /> +<small>PROFESSOR AT MARBURG.</small> +</p> + +<p>'This work is now issued for the third time as an independent +treatise. It admirably epitomizes the subject, and exhibits on almost +every page evidences of Professor Wellhausen's profound study.'—<i>Publishers' +Circular.</i></p> + +<p>'We would only say that those who differ from his critical views +will yet do well to study them, and to read this history in which +he applies them. Its separate publication, in a handy form and at +a moderate price, makes it generally accessible.'—<i>North British +Daily Mail.</i></p> + +<p>'The publication in a separate form of Professor Wellhausen's +article in the "Encyclopædia Britannica" on "Israel" will be very +warmly welcomed by many readers.'—<i>Manchester Guardian.</i></p> + +<p>'We are very glad to welcome an edition of Professor Wellhausen's +"Sketch of the History of Israel and Judah" in a convenient +and handy form. This is the first time it has appeared in +a separate form. It is already known to students; it ought now +to become popular. It is based on the learned author's studies in +Hebrew literature and history, and, though not controversial in form, +it differs totally from orthodox presentations of the subject.'—<i>Westminster +Review.</i></p> + +<p>'A sketch which has created such widespread and profound +interest as this could not be kept in the pages of a voluminous +encyclopædia. Wellhausen's words necessarily have exceptional +importance, even in the esteem of those who differ from him <i>toto +cœlo</i>.'—<i>Baptist Magazine.</i></p> + +<p>'The profound scholarship of the author does not elevate his +writing above the interest of the general reader, and a vivid idea +of the involved Jewish history is obtainable from this volume.'—<i>Christian +Advocate.</i></p> + +<p class="center">LONDON: ADAM & CHARLES BLACK, SOHO SQUARE.</p> +<p><span class="pagenum"><a name="Page_160" id="Page_160">[Pg 160]</a></span></p> +<hr class="tb"/> +<p class="center"> <i>Demy 8vo., boards, price 3s. 6d. net.</i></p> + +<p class="center"><big>A CLASSIFICATION OF VERTEBRATA,</big><br /> + RECENT AND EXTINCT.</p> + +<p class="center"> With Diagnoses and Definitions, a Chapter on Geographical + Distribution, and an Etymological Index.</p> + +<p class="center"> By HANS GADOW, M.A., <span class="smcap">Ph.D.</span>, F.R.S.,</p> + +<p class="center"><small>STRICKLAND CURATOR AND LECTURER ON ZOOLOGY TO THE UNIVERSITY, + CAMBRIDGE.</small> +</p> + +<p>'At the end of his work Dr. Gadow adds a useful chapter on the geographical +distribution of the Vertebrata, with a table showing the approximate number of +the known recent species. He also gives a fanciful though striking calculation +to show how some groups are still in the ascendant, while others are distinctly +declining. The little volume is indeed a welcome addition to the biological +student's library, and it deserves the wide circulation which its author's eminence +is likely to ensure for it.'—<i>Natural Science.</i></p> + +<p>'It is a book, it need hardly be said, for the student; it is simply a list of the +principal sub-divisions of backboned animals, with just as much definition as is +needed. It may be regarded as an exceedingly concentrated extract of a full +text-book of the vertebrates.'—<i>Daily Chronicle.</i></p> + +<p class="center">LONDON: ADAM & CHARLES BLACK, SOHO SQUARE.</p> +<hr class="tb"/> + + +<p class="center"> <i>Demy 8vo., cloth, price 21s.</i></p> + +<p class="center"><big>IN NORTHERN SPAIN.</big></p> + +<p class="center"> By Dr. HANS GADOW, M.A., <span class="smcap">Ph.D.</span>, F.R.S.</p> + +<p class="center"> <i>Containing Map and 89 Illustrations.</i> +</p> + +<p>'Some years back "Wild Spain," one of the best books of its kind, made you +desirous of knowing more of the country. And Hans Gadow has deepened this +feeling in his excellent volume "In Northern Spain," and that to an enormous +extent. Dwelling at inn or farm, or in their own tent, they saw the country as +it has been seen but rarely, and they came to know the inhabitants as they can +be known in no other fashion.'—<i>Black and White.</i></p> + +<p>'To persons visiting the provinces with which the author deals, this book will +be invaluable, and will do more to point their attention to objects of interest than +existing guide-books of Spain, most of which are out of date.'—<i>The Field.</i></p> + +<p>'About the best book of European travel that has appeared these many +years.'—<i>Literary World.</i></p> + +<p class="center">LONDON: ADAM & CHARLES BLACK, SOHO SQUARE.</p> + + +<div class="footnotes"><h3>FOOTNOTES:</h3> + +<div class="footnote"> + +<p><a name="Footnote_1_1" id="Footnote_1_1"></a><a href="#FNanchor_1_1"><span class="label">[1]</span></a> See note,p.<a name="FNanchor_40" id="FNanchor_40"></a><a href="#Footnote_40">80.</a> </p> + +<p><a name="Footnote_2_2" id="Footnote_2_2"></a><a href="#FNanchor_2_2"><span class="label">[2]</span></a> See note, p.<a name="FNanchor_41" id="FNanchor_41"></a><a href="#Footnote_41">89.</a></p> + +<p><a name="Footnote_3_3" id="Footnote_3_3"></a><a href="#FNanchor_3_3"><span class="label">[3]</span></a> +See notes, p. <a name="FNanchor_42" id="FNanchor_42"></a><a href="#Footnote_42">102</a>, <a name="FNanchor_43" id="FNanchor_43"></a><a href="#Footnote_43">106</a>. </p> + +<p><a name="Footnote_5_5" id="Footnote_5_5"></a><a href="#FNanchor_5_5"><span class="label">[5]</span></a> +See note, p. <a name="FNanchor_44" id="FNanchor_44"></a><a href="#Footnote_44">80.</a> </p> + +<p><a name="Footnote_6_6" id="Footnote_6_6"></a><a href="#FNanchor_6_6"><span class="label">[6]</span></a> <i>Perfect</i>, in the sense of highest stage of evolution, may +seem a <i>petitio principii</i>. Leaving aside the consideration +that no living creature is absolutely perfect, in the sense that +its organization cannot become more efficient or proficient, +we have here to deal with relative perfection of the whole +organization. A fish or a snake is in its way more specialized +than a mammal; but specialization does not necessarily +mean height of development: it generally means life in a +comparatively narrow groove. The acts of giving birth and +nourishing the young with the mother's milk is a much +higher stage than the act of laying eggs and letting them +run their chance. The development of a hairy coat goes +along with heightened temperature of the blood, subsequent +greater independence of the surrounding temperature, and +increased steady activity of the brain and other nerve-centres. +The brain of the Mammalia, in its minute structure, +is much more complex. This rule applies to some of +the principal sense organs, chiefly the nose and the ear. +The skeleton, not so much as a whole as in the various bones +and joints, is more neatly finished, and built up more in +conformity with 'scientific principles,' than is the case even +with birds, in spite of their marvellous specialization. The +same is the case with the vascular system, notably the heart +and the veins, and with the excretory organs. In all of these +many imperfections, still to be found in the other classes, +have been corrected in Mammalia. The Primates take an +easy first by their hands, and among them the apes and man +himself by their brains.</p> + +<p><a name="Footnote_7_7" id="Footnote_7_7"></a><a href="#FNanchor_7_7"><span class="label">[7]</span></a> 'Die menschenähnlichen Affen und ihre Organisation +im Vergleich zur menschlichen.' 1883.</p> + +<p><a name="Footnote_8_8" id="Footnote_8_8"></a><a href="#FNanchor_8_8"><span class="label">[8]</span></a> G. Schwalbe, 'In wiefern ist die menschliche Ohrmuschel ein +rudimentäres Organ?'—In what Respects is the Human Outer Ear a +Rudimentary Organ? (<i>Archiv f. Anatomie und Physiologie</i>, 1889).</p> + +<p><a name="Footnote_9_9" id="Footnote_9_9"></a><a href="#FNanchor_9_9"><span class="label">[9]</span></a> Wiedersheim, 'Der Bau des Menschen als Zeugniss für +seine Vergangenheit.' Freiburg, 1888. Translated: 'The +Structure of Man an Index to his Past History.' London, +1895.</p> + +<p><a name="Footnote_10_10" id="Footnote_10_10"></a><a href="#FNanchor_10_10"><span class="label">[10]</span></a> <i>Pithecanthropus erectus.</i> 'Eine menschenähnliche +Uebergangsform aus Java' ('A Human-like Transitional +Form'). Batavia, 1894.</p> + +<p><a name="Footnote_11_11" id="Footnote_11_11"></a><a href="#FNanchor_11_11"><span class="label">[11]</span></a> On the day after the delivery of this address Dr. Dubois +exhibited the cranium of Pithecanthropus, from which he had +removed the stony matrix which filled the inside, in order to +examine the impression left by the cerebral convolutions. +He was able to show that they also are very human, and +more highly developed than those of the recent apes.</p> + +<p><a name="Footnote_12_12" id="Footnote_12_12"></a><a href="#FNanchor_12_12"><span class="label">[12]</span></a> L. Manouvier: 'Deuxième étude sur le Pithecanthropus erectus +comme précurseur présumé de l'homme.' (<i>Bulletins de la Soc. +d'Anthropologie de Paris</i>, 1895.)</p> + +<p><a name="Footnote_13_13" id="Footnote_13_13"></a><a href="#FNanchor_13_13"><span class="label">[13]</span></a> +See notes, p. <a name="FNanchor_45" id="FNanchor_45"></a><a href="#Footnote_45">93.</a> </p> + +<p><a name="Footnote_14_14" id="Footnote_14_14"></a><a href="#FNanchor_14_14"><span class="label">[14]</span></a> +See notes, p. <a name="FNanchor_46" id="FNanchor_46"></a><a href="#Footnote_46">87.</a> </p> + +<p><a name="Footnote_15_15" id="Footnote_15_15"></a><a href="#FNanchor_15_15"><span class="label">[15]</span></a> +</p> + +<blockquote> + +<p><span class="smcap">F. Ameghino</span>: 'Contribucion al conocimiento de los +mamíferos de la república Argentina.' In <i>Actas de +la Academia nacional de Sciencias en Cordoba</i>, +1889.—Another article in <i>Revista Argentina de Historia +natural</i>. Buenos Aires, 1891. +</p> +<p> +<span class="smcap">A. Gaudry</span>: 'Animaux fossiles et géologie de l'Attique.' +1862.—'Le Dryopithèque.' <i>Mém. Soc. géol. de +France</i>: 'Paléontologie.' 1890. +</p> +<p> +<span class="smcap">O. Marsh</span>: 'Introduction and Succession of Vertebrate +Life in America.' Address, Amer. Assoc. Adv. Sci., +Nashville, 1887. +</p> +<p> +<span class="smcap">H. F. Osborn</span>: 'The Rise of the Mammalia in North +America.' Address, Amer. Assoc. Adv. Sci., Madison, +1893. +</p> +<p> +<span class="smcap">L. Ruetimeyer</span>: 'Ueber die Herkunft unserer Thierwelt,' +Basel, 1867. +</p> +<p> +<span class="smcap">C. S. Forsyth Major</span>: 'Fossil Monkeys from Madagascar.' +<i>Geological Magazine</i>, 1896. +</p> +<p> +<span class="smcap">M. Schlosser</span>: 'Ueber die Beziehungen der ausgestorbenen +Saeugethierfaunen und ihr Verhaeltniss zur Saeugethierfauna +der Gegenwart.' Biolog. Centralblatt, 1888.</p> +</blockquote> + +<p><a name="Footnote_16_16" id="Footnote_16_16"></a><a href="#FNanchor_16_16"><span class="label">[161</span></a> +See notes, p. <a name="FNanchor_47" id="FNanchor_47"></a><a href="#Footnote_47">102</a>, <a name="FNanchor_48" id="FNanchor_48"></a><a href="#Footnote_48">106</a>. </p> + +<p><a name="Footnote_17_17" id="Footnote_17_17"></a><a href="#FNanchor_17_17"><span class="label">[171</span></a> +See note, p. <a name="FNanchor_49" id="FNanchor_49"></a><a href="#Footnote_49">97</a>.</p> + +<p><a name="Footnote_18_18" id="Footnote_18_18"></a><a href="#FNanchor_18_18"><span class="label">[18]</span></a> Wilhelm Bischoff of Munich: works on the history +of the development of the rabbit, dog, guinea-pig, roe-deer. +1840-1854.</p> + +<p><a name="Footnote_19_19" id="Footnote_19_19"></a><a href="#FNanchor_19_19"><span class="label">[191</span></a> +See note, p. <a name="FNanchor_50" id="FNanchor_50"></a><a href="#Footnote_50">96</a>. </p> + +<p><a name="Footnote_20_20" id="Footnote_20_20"></a><a href="#FNanchor_20_20"><span class="label">[20]</span></a> 'Ueber die Entwicklung der einfachen Ascidien,' Mém. +Acad. St. Petersbourg, vii. ser., tome x. (1866). Other +papers in 'Archiv f. Mikroskop. Anatomie,' vii. (1871); xiii. +(1877).</p> + +<p><a name="Footnote_21_21" id="Footnote_21_21"></a><a href="#FNanchor_21_21"><span class="label">[21]</span></a> +See notes, p. <a name="FNanchor_51" id="FNanchor_51"></a><a href="#Footnote_51">102</a>, <a name="FNanchor_52" id="FNanchor_52"></a><a href="#Footnote_52">106</a>.</p> + +<p><a name="Footnote_22_22" id="Footnote_22_22"></a><a href="#FNanchor_22_22"><span class="label">[22]</span></a> Similar conditions seem to have prevailed among the +Proreptilia; but in those of their descendants which have +specialized into Reptiles and Birds the basi-occipital element +becomes more and more predominant in that formation +which ultimately leads to the apparently single condyle. +Hence it is misleading to divide the Tetrapoda into the two +main groups of Amphi-and Mono-condylia, and therefrom +to conclude that the two-condyled Mammalia are more +closely related to the likewise amphicondylous Amphibia +than to the so-called monocondylous Reptiles.</p> + +<p><a name="Footnote_23_23" id="Footnote_23_23"></a><a href="#FNanchor_23_23"><span class="label">[23]</span></a> 'Ergebnisse naturwissenschaftlicher Forschungen auf +Ceylon,' vols. 4 and 5. (With an atlas of 84 plates; 1893.)</p> + +<p><a name="Footnote_24_24" id="Footnote_24_24"></a><a href="#FNanchor_24_24"><span class="label">[24]</span></a> 'Principles of Biology': 'The Factors of Organic Evolution'; +'The Inadequacy of Natural Selection.'</p> + +<p><a name="Footnote_25_25" id="Footnote_25_25"></a><a href="#FNanchor_25_25"><span class="label">[25]</span></a> Abridged from Haeckel's 'Systematische Phylogenie +der Vertebraten,' § 14.</p> + +<p><a name="Footnote_26_26" id="Footnote_26_26"></a><a href="#FNanchor_26_26"><span class="label">[26]</span></a> That this great work is now comparatively rare, although +still in the second-hand market, may perhaps be urged in +excuse of the fact of so many attempts made by many authors, +both professional and amateur, to find fault with or to +explain the principles of adaptation, variation, heredity, +cænogenesis, phylogeny, etc., in complete ignorance that +all these and many more fundamental questions were fully +discussed more than thirty years ago in the 'Generelle Morphologie.'</p> + +<p><a name="Footnote_27_27" id="Footnote_27_27"></a><a href="#FNanchor_27_27"><span class="label">[27]</span></a> James Croll: 'On Geological Time, and the Probable +Date of the Glacial and Upper Miocene Period,' <i>Philos. +Magazine</i>, xxxv., 1868, pp. 363-384; xxxvi., pp. 141-154; +362-386.</p> + +<p><a name="Footnote_28_28" id="Footnote_28_28"></a><a href="#FNanchor_28_28"><span class="label">[28]</span></a> William Thomson: 'On the Secular Cooling of the +Earth,' <i>Transact. R. S. Edinb.</i>, xxiii., 1864, pp. 157-169.</p> + +<p><a name="Footnote_29_29" id="Footnote_29_29"></a><a href="#FNanchor_29_29"><span class="label">[29]</span></a> 'Geological Time as indicated by the Sedimentary +Rocks of North America.' <i>Proc. Amer. Assoc. Adv. Sci.</i>, +xlii., 1893, pp. 129-169.</p> + +<p><a name="Footnote_30_30" id="Footnote_30_30"></a><a href="#FNanchor_30_30"><span class="label">[30]</span></a> Henry Shaler Williams, 'Geological Biology.' New +York, 1895.</p> +</div> +</div> + +<p class= "transnote"> +Transcriber's Notes<br /> + + Variations in spelling, punctuation and hyphenation have been retained + except in obvious cases of typographical errors. + Inconsistent hyphenation and spelling are as in the original. + The layout of the chart Ancestral Tree of The Mammalia has been changed + from the original to enhance clarity, the essential relationships have + been preserved. + The second reference to footnote 3, in the same paragraph as the first, + has been left blind as it is redundant. +</p> + +<div>*** END OF THE PROJECT GUTENBERG EBOOK 44541 ***</div> +</body> +</html> diff --git a/44541-h/images/cover.jpg b/44541-h/images/cover.jpg Binary files differnew file mode 100644 index 0000000..dd90753 --- /dev/null +++ b/44541-h/images/cover.jpg diff --git a/44541-h/images/i_0231.jpg b/44541-h/images/i_0231.jpg Binary files differnew file mode 100644 index 0000000..52420cd --- /dev/null +++ b/44541-h/images/i_0231.jpg diff --git a/44541-h/images/i_0331.jpg b/44541-h/images/i_0331.jpg Binary files differnew file mode 100644 index 0000000..263fc4b --- /dev/null +++ b/44541-h/images/i_0331.jpg |
