Chapter III: The Origin of the Human Body (1)

In an article published August 31, 1895, in the _New York Freeman’s Journal_, the late Rev. J. A. Zahm gave expression to the following opinion: “The evolution of the body of man from some inferior animal and its subsequent endowment in this body by God of a rational soul is antagonistic to no dogma of faith and may be shown to be in harmony with the teachings of St. Thomas.” The scriptural and theological aspect of this view need not concern us here, our sole purpose being to evaluate it from a purely scientific standpoint. Once evolutionary thought takes cognizance of the fact that the human soul is a spiritual principle underivable from mere matter, once it acknowledges the immediate creation of the human soul, and professes to do no more than account for the origin of man’s animal _body_, that moment is it shorn of its materialistic implications; but what, we may ask, are the foundations of such an hypothesis in the realm of scientific fact?

The writer must confess that he cannot fathom the mentality of those who accept the evolutionary explanation, so far as plant and animal organisms are concerned, but proceed to draw the line when it comes to applying it to the human body. For if one (to borrow Du Bois-Reymond’s expression) “gives so much as his little finger to” the evolutional argument from organic homology, he must end, in so far as he is consistent, in acknowledging as incontestable its obvious application to man. The only choice which sound logic can sanction is between fixism and a thoroughgoing system of transformism, which does not exempt the human body from the scope of the evolutionary explanation. Indeed, the theory of evolution itself stands or falls upon this issue; for, if structures so strikingly similar as the skeletons of a man and an ape, respectively, have originated from two distinct ancestral stocks, then in no case at all is the inference of common descent from structural resemblance a legitimate procedure. In other words, if the homologies existent between the human and simian organisms are explicable on some other basis than that of common ancestry, then all organic homologies are so explicable, and the whole evolutionary argument collapses.

§ 1. Two Theories of Descent

Two theories have been formulated regarding the alleged bestial origin of the human body: (1) the theory of lineal descent from some known species (living or fossil) of ape or monkey; (2) the theory of collateral descent from a hypothetical bestial ancestor common to apes and men. The theory of lineal descent is that to which Darwin himself stands committed. This theory, however, soon fell into disrepute among scientists, who came to prefer the theory of collateral descent, although signs of a return to the older theory are not wanting in our day. At all events, Darwin came out flatly in favor of the monkey origin of man. This, it is true, has been indignantly denied by loyal partisans anxious to exonerate their idol from the reproach of having advanced a crude and now obsolete theory of human descent. But Darwin’s own words speak for themselves: “The Simiadae,” he says, “then branched off into two great stems, the New World and Old World monkeys; and from the latter, at a remote period of time, Man, the wonder and glory of the Universe, proceeded.” (“Descent of Man,” 2nd ed., ch. VI, pp. 220, 221.) Note that he does not say “probably”; his language is not the language of hypothesis, but of categorical affirmation.

The theory, however, which is most generally favored at the present time holds that, assuming the universality of the evolutionary process, all existing types must be of equal antiquity, and none prior or ancestral to any other. Hence it regards man, not as the direct descendant of any known type of ape, but as the offspring of an as yet undiscovered Tertiary ancestor, from which men and apes have diverged in two distinct lines of descent. “_Monkeys, apes, and men_,” says Conklin, “_have descended from some common but at present extinct ancestor_. Existing apes and monkeys are collateral relatives of man but not his ancestors; his cousins but not his parents.... The human branch diverged from the anthropoid stock not less than two million years ago, and since that time man has been evolving in the direction represented by existing human races, while the apes have been evolving in the direction represented by existing anthropoids. During all this time men and apes have been growing more and more unlike and conversely the farther back we go, the more we should find them converging until they meet in a common stock which should be intermediate between these two stocks.” (“Evolution and the Bible,” pp. 12, 13—italics his.)

Barnum Brown’s recent discovery of three jaws of the fossil ape _Dryopithecus_ in the Siwalik Hills of India has, as previously intimated, resulted in a return on the part of certain scientists, _e.g._ Wm. K. Gregory and Dudley J. Morton, to views that more nearly approximate those of Charles Darwin. According to these men, the fossil anthropoid _Dryopithecus_ is to be regarded as the common ancestor of men, chimpanzees, and gorillas. (Cf. _Science_, April 25, 1924, Suppl. XII.)

Many considerations, however, militate against the direct derivation of man’s bodily frame from any known species of ape, whether living or fossil. Dana has pointed out that, as regards the mechanism of locomotion, man belongs to a more primitive type than the ape. The earliest and lowest type of vertebrates are the fish, and these, according to the above-mentioned author, are _urosthenic_ (tail-strong), inasmuch as they propel themselves by means of their tails. Next in point of organization and time came the _merosthenic_ vertebrates, which have their strength concentrated in the hind-limbs, _e.g._ reptiles like the dinosaurs. In the last place come the _prosthenic_ vertebrates, whose strength is concentrated in the fore-limbs, _e.g._ the carnivora and apes. Now man belongs to the _merosthenic_ type, and his mode of progression, therefore, is more primitive than that of apes, which are _prosthenic_, all anthropoid apes, such as the gorilla, the chimpanzee, the orang-utan and the gibbon having longer fore-limbs than hind-limbs.

The striking anatomical differences between apes and men, though not of sufficient importance to exclude the possibility of collateral relationship, are so many solid arguments against the theory of direct descent. We will content ourselves with a mere enumeration of these differences. In the ape, the cranium has a protruding muzzle and powerful jaws equipped with projecting canine teeth, but the brain-case is comparatively small; in man, on the contrary, the facial development is insignificant and the teeth are small and vertical, while the brain-case is enormous in size, having at least twice the capacity of that of an ape. “The face of man,” to quote Ranke, “slides, as it were, down from the forehead and appears as an appendix to the front half of the skull. But the gorilla’s face, on the contrary, protrudes from the skull, which in turn slides almost entirely backward from the face. By a cross-cut one may sever the whole face from the skull, except a very small part near the sockets, without being forced to open up the interior of the skull. It is only on account of its protruding, strongly developed lower parts that the skull-cap of the animal can simulate a kind of human face.” (“Der Mensch,” vol. II, p. 401.) These differences may be summarized by saying that the head of the ape is specialized for mastication and defense, whereas the head of man is specialized for psychic functions. Again, as we have seen, the fore-limbs of the ape are long, and its hind-limbs short, the extremities of both the latter and the former being specialized primarily for prehension and only secondarily for progression. This is due to the ape’s adaptation to arboreal life. In man, however, the arms are short and specialized for prehension alone, while the legs are long and terminate in broad plantigrade feet specialized for progression alone. Man, consequently, is not adapted to arboreal life. In the ape, the spine has a single curve, and the occipital foramen (the aperture through which the spinal cord enters the brain-case) is eccentrically located in the floor of the cranial box; in man, the spine has a double curve, and the occipital foramen is centrally located, both features being in adaptation to the upright posture peculiar to man—“_die zentralle Lage dieser Oeffnung_,” says Ranke alluding to the occipital foramen of man, “_in der Schädelbasis ist für den Menschenschädel im Unterschied gegen den Tierschädel eine in hohem Masse typische_.” (“Der Mensch,” vol. I, p. 378.) In the ape, therefore, the vertebræ have an adaptation producing convexity of the back, precluding a normal upright posture, and enforcing progression on all fours. It has, moreover, powerful muscles at the back of the neck to carry the head in the horizontal position necessitated by this mode of progression. In man “the skull has the occipital condyles placed within the middle fifth, in adaptation to the vertical position of the spine” (Nicholson), the spinal cord enters the cranial box at a perpendicular, and the head balances on the spinal column as on a pivot, all of which ensures the erect posture and bipedal progression in man. There are, moreover, no neck muscles to support the head in any other than the vertical position. There are many other differences, besides: the ape, for example, has no chin, while in man there is a marked mental protuberance; man has a slender waist, but the ape has a barrel-like torso without any waist; the ape has huge bony ridges for the attachment of muscles, _e.g._ the sagittal crest, the superciliary ridges, etc., while in man such features are practically absent.

Ranke has given a very good summary of the chief anatomical differences between man and the anthropoid apes: “The gorilla’s head leaning forward, hangs down from the spinal column, and his chinless snout, equipped with powerful teeth, touches the breastbone. Man’s head is round, and resting on a free neck, balances unrestrained upon the spinal column. The gorilla’s body, without a waist, swells out barrel-shaped, and when straightened up finds no sufficient support on the pelvis; the back-bone, tailless as in man, but almost straight, loses itself without nape or neck formation properly so-called in the rear part of the head and without protuberance of the gluteal region in the flat thighs. Man’s body is slightly molded, like an hour-glass, the chest and abdomen meeting to form a waist where they are narrowest; the abdominal viscera are perfectly supported in the pelvis as in a plate; and elegance is decidedly gained by the double S-line, which, curving alternately convex and concave, passes from the crown through the neck and nape, down the back to the base of the spine and the gluteal region. The normal position of the gorilla shows us a plump, bear-like trunk, carried by short, crooked legs and by arms which serve as crutches and touch the ground with the knuckles of the turned-in fingers. The posture of the body is perfectly straight in man, it rests on the legs as on columns when he stands upright, and his hands hang down on both sides always ready for use. The gorilla is thickly covered with hair, while man’s body on the whole is naked.” (_Op. cit._, vol. II, p. 213.)

In conclusion, we may say that, while there is a general resemblance between the human body and that of an anthropoid ape, there is, likewise, a particular divergence—“there is no bone, be it ever so small, nay, not even the smallest particle of a bone, in which the general agreement in structure and function would pass over into real identity.” (Ranke, _op. cit._, vol. I, p. 437.) Hence Virchow declares that “the differences between man and monkey are so wide that almost any fragment is sufficient to diagnose them.” (Smithson. Inst. Rpt. for 1889, p. 566.) These differences are so considerable as to preclude the possibility of a _direct_ genealogical connection between man and any known type of ape or monkey—“The testimony of comparative anatomy,” to quote Bumüller, “is decidedly against the theory of man’s descent from the ape.” (“Mensch oder Affe?” p. 59.) Ranke has somewhere called man a brain-animal, and this sums up the chief difference, which marks off the human body from all bestial organisms. In the ape the brain weighs only 100th part of the weight of its body, whereas in man the brain has a weight equivalent to the 37th part of the weight of the human body. The cranial capacity of the largest apes ranges from 500 to 600 c.cm., while the average cranial capacity in man is 1500 c.cm. Moreover, the human brain is far more extensively convoluted within the brain-case than that of an ape, so much so that the surface or cortical area of the human brain is four times as great as that of the ape’s brain. Thus Wundt, in his “Grundzüge der physiologischen Psychologie,” cites H. Wagner as assigning to man a brain surface of from 2,196 to 1,877 sq. cm., but a cortical area of only 535 sq. cm. in the case of an orang-outang. (Cf. English Translation by Titchener, vol. I, p. 286.)

Another difficulty in the way of the Darwinian theory of direct descent is the fact that the best counterparts of human anatomy are not found united in any one species of ape or monkey, but are scattered throughout a large number of species. “Returning to the old discussion,” says Thomas Dwight, “as to which ape can boast of the closest resemblance to man, Kohlbrugge brings before us Aeby’s forgotten book on the skull of man and apes. His measurements show that the form nearest to man among apes is the gibbon, or long-armed ape, but that the South American monkey _Crysothrix_ is nearer still. Aeby recognized what modern anatomists have forgotten or wilfully ignored: that any system of descent is inadequate which does not recognize that the type of man is not in any one organ, but in all the physical and psychological features. He declared that while we are far from having this universal knowledge, we have learned enough about the various parts of the body to make it impossible for us to sketch any plan of descent. ‘It almost seems as if every part had its own line of descent, different from that of others.’ ... Kohlbrugge now introduces Haacke, who denies any relationship between man and apes, the latter being instances of one-sided development. He even dares to declare anyone who speaks of an intermediate form between man and apes to be ignorant of the laws of development governing the race history of mammals. He believes man came from some lemuroid form, which may have descended from the insectivora.” (“Thoughts of a Catholic Anatomist,” pp. 188-190.)

All known types, then, of apes and monkeys are too specialized to have been in the direct line of human descent. Man, as Kohlbrugge ironically remarks, appears to have come from an ancestor much more like himself than any species of ape we know of. Moreover, no species of apes or monkeys monopolizes the honors of closest resemblance to man. In many points, the South American monkeys, though more primitive than the anthropoid apes, are more similar to man than the latter.

§ 2. Embryological Resemblances

Much has been made of the so-called biogenetic law as an argument for the bestial origin of mankind. This theory of the embryological recapitulation of racial history was first formulated by Fritz Müller. Haeckel, however, was the one who exploited it most extensively, and who exalted it to the status of “the fundamental law of biogenesis.”[16] The latter’s statement of the principle is as follows: “_Die Ontogenesis ist die Palingenesis der Phylogenesis_.”—Ontogeny (the development of the individual) is a recapitulation of phylogeny (the development of the race). For a long time this law was received with uncritical credulity by the scientific world, but enthusiasm diminished when more careful studies made it clear that the line of descent suggested by embryology did not agree with what was inferred from comparative anatomy and the sequence of fossil forms. Besides, it was manifest that certain organs in embryos were distinctively _embryonic_ and could never have functioned in adult forms, _e.g._ the yolk sac and the amnion. “It was recognized,” says T. H. Morgan, “that many embryonic stages could not possibly represent ancestral animals. A young fish with a huge yolk sac attached could scarcely ever have led a happy, free life as an adult individual. Such stages were interpreted, however, as _embryonic_ additions to the original ancestral type. The embryo had done something on its own account. In some animals the young have structures that attach them to the mother, as does the placenta of mammals. In other cases the young develop membranes about themselves—like the amnion of the chick and the mammal—that would have shut off an adult animal from all intercourse with the outside world. Hundreds of such embryonic structures are known to embryologists. These were explained as adaptations and as falsifications of the ancestral records.” (“Critique of the Theory of Evolution,” pp. 16, 17.)

[16] Haeckel’s “Biogenetisches Grundgesetz,” which he
formulates thus: “_Die Ontogenie (Keimesgeschichte) ist eine
kurze Wiederholung der Phylogenie (Stammesgeschichte)_,” 1874.

The result has been that this so-called law has fallen into general disrepute among scientists, especially as a means of reconstructing the phylogeny of modern organisms. It is recognized, of course, that comparative embryology can furnish embryological homologies analogous to the homologies of comparative anatomy, but it is now generally acknowledged that the view, which regards the embryological process as an abridged repetition of the various states through which the species has passed in its evolutionary career must be definitively abandoned, and that, as a general law of organic development, the biogenetic principle has been thoroughly discredited. “This law,” says Karl Vogt of Geneva, “which I long held as well-founded, is absolutely and radically false. Attentive study of embryology shows us, in fact, that embryos have their own conditions suitable to themselves, and very different from those of adults.” (Quoted by Quatrefages De Breau, in his “Les Emules de Darwin,” vol. II, p. 13.) “There can no longer be question,” says Prof. M. Caullery of the Sorbonne, “of systematically regarding individual development as a repetition of the history of the stock. This conclusion results from the very progress made under the inspiration received from this imaginary law, the law of biogenesis.” (Smithson. Inst. Rpt. for 1916, p. 325.)

This collapse of the biogenetic law has tumbled into ruins the elaborate superstructure of genealogy which Haeckel had reared upon it. His series of thirty stages extending from the fictitious “cytodes” up to man, inclusively, is even more worthless today than it was when Du Bois-Reymond made his ironic comment: “Man’s pedigree, as drawn up by Haeckel, is worth about as much as is that of Homer’s heroes for critical historians.” (_Revue Scientifique_, 1877, I, p. 1101.) Haeckel tried in vain to save his discredited law by means of the expedient of _cænogenesis_, that is, “the falsification of the ancestral record (palingenesis).” That Nature should be guilty of “falsification” is an hypothesis not to be lightly entertained, and it is more credible, as Wasmann remarks, to assume that Haeckel, and not Nature, is the real falsifier, inasmuch as he has misrepresented Nature in his “fundamental biogenetic law.” Cænogenesis is a very convenient device. One can alternate at will between _cænogenesis_ and _palingenesis_, just as, in comparative anatomy, one can alternate capriciously between _convergence_ and _homology_, on the general understanding of its being a case of: “Heads, I win; tails, you lose”—certainly, there is no _objective_ consideration to restrain us in such procedure. “Such weapons as Cænogenesis and Convergence,” says Kohlbrugge (in his “Die Morphologische Abstammung des Menschen,” 1908) “are unfortunately so shaped that anyone can use them when they suit him, or throw them aside when they do not. They show, therefore, in the prettiest way the uncertainty even now of the construction of the theory of descent. As soon as we go into details it leaves us in the lurch; it was only while our knowledge was small that everything seemed to fit together in most beautiful order.” (Quoted by Dwight in “Thoughts of a Catholic Anatomist,” p. 187.)

It is undeniable, indeed, that in many cases the young of higher animals pass through stages in which they bear at least a superficial resemblance to adult stages in inferior and less complex organisms. Obviously, however, there cannot be any direct derivation of the _embryonic_ features of one organism from the _adult_ characters of another organism. This preposterous implication of the Müller-Haeckel Law must, as Morgan points out, be entirely eliminated, before it can merit serious consideration. Referring to the spiral cleavage exhibited by annelid, planarian and molluscan eggs, Morgan says: “It has been found that the cleavage pattern has the same general arrangement in the early stages of flat worms, annelids and molluscs. Obviously these stages have never been adult ancestors, and obviously if their resemblance has any meaning at all, it is that each group has retained the same general plan of cleavage possessed by their common ancestor.... Perhaps someone will say, ‘Well! is not this all that we have contended for! Have you not reached the old conclusion in a roundabout way?’ I think not. To my mind there is a wide difference between the old statement that the higher animals living today have the original adult stages telescoped into their embryos, and the statement that the resemblance between certain characters in the embryos of higher animals and corresponding stages in the embryos of lower animals is most plausibly explained by the assumption that they have descended from the same ancestors, and that their common structures are embryonic survivals.” (_Op. cit._, pp. 22, 23.)

After this admission, however, nothing remains of the law of “recapitulation” except simple embryological homology comparable, in every sense, to adult homology, and adding nothing essentially new to the latter argument for evolution. It is, therefore, ridiculous for evolutionists to speak of _branchial_ (gill) arches and clefts in man. The visceral or pharyngeal arches and grooves appearing in the human embryo are unquestionably homologous with the genuine branchial arches and clefts in a fish embryo. In the latter, however, the grooves become real clefts through perforation, while the arches become the lamellæ of the permanent gills, thus adapting the animal to aquatic respiration. It is, accordingly, perfectly legitimate to refer to these embryonic structures in the young fish as gill arches and gill clefts. In man, however, the corresponding embryonic structures develop into the oral cavity, auditory meatus, ossicles of the ear, the mandible, the lower lip, the tongue, the cheek, the hyoid bone, the styloid process, the thymus, the thyroid and tracheal cartilages, etc. There is no perforation of the grooves, and the arches develop into something quite different than branchial lamellæ. Hence the correct name for these structures in the human embryo is _pharyngeal_ (visceral) arches and grooves, their superficial resemblance to the embryonic structures in the fish embryo being no justification for calling them branchial. In short, the mere fact that certain embryonic structures in the young fish (homologous to the pharyngeal arches and grooves in the human embryo) develop into the permanent gills of the adult fish, is no more significant than the association of homology with divergent preadaptations, which is of quite general occurrence among adult vertebrate types. In all such cases, we have instances of fundamentally identical structures, diverted, as it were, to entirely different purposes or functions (_e.g._ the arm of a man and the flipper of a whale). Hence the argument drawn from embryological homology is no more cogent than the argument drawn from the homologies of comparative anatomy, which we have already discussed in a previous chapter. The misuse of the term _branchial_, to prejudge matters in their own favor, is in keeping with the customary policy of evolutionists. It is intended, naturally, to convey the impression that man, in the course of his evolution, has passed through a fish-like stage. At bottom, however, it is nothing more than a verbal subterfuge, that need not detain us further.

The theory of embryological recapitulation is often applied to man, with a view to establishing the doctrine of his bestial ancestry. We have seen one instance of this application, and we shall consider one other, for the purpose of illustrating more fully the principles involved. The claim is made by evolutionists, that man must have passed through a fish or amphibian stage, because, in common with all other mammals, he exhibits, during his embryological development, a typical fish (or, if you prefer, amphibian) kidney, which subsequently atrophies, only to be replaced by the characteristic mammalian kidney. The human embryo, therefore, repeats the history of our race, which must have passed through a fish-like stage in the remote past. In consequence of this phenomenon, therefore, it is inferred that man must have had fish-like ancestors. Let us pause, however, to analyze the facts upon which this inference is based.

In annelids, like the earthworm, the nephridia or excretory tubules are arranged segmentally, one pair to each somite. In vertebrates, however, the nephridial tubules, instead of developing in regular sequence from before backwards, develop in three batches, one behind the other, the anterior batch being called the _pronephros_, the middle one, the _mesonephros_ and the posterior one, the _metanephros_. This, according to J. Graham Kerr, holds true not only of the amniotic vertebrates (reptiles, birds, and mammals) but also, with a certain reservation, of the anamniotic vertebrates (fishes and amphibians). “In many of the lower Vertebrates,” says this author, “there is no separation between the mesonephros and metanephros, the two forming one continuous structure which acts as the functional kidney. Such a type of renal organ consisting of the series of tubules corresponding to mesonephros together with metanephros may conveniently be termed the opisthonephros.” (“Textbook of Embryology,” II—Vertebrata, p. 221.) If we accept this view, it is not quite accurate to regard the mesonephros in man as a homologue of the _opisthonephros_ of a fish, seeing that the latter is composed not only of mesonephridia (mesonephric tubules), but also of metanephridia (metanephric tubules). A brief description of the three nephridial systems of vertebrate embryos will serve to further clarify their interrelationship.

(1) _The pronephric system_: This consists of a collection of tubules called the pronephros, and a pronephric duct leading to the cloaca, or terminal portion of the alimentary canal. The pronephros is a functional organ in the frog tadpole and other larval amphibia. It is also found in a few teleosts, where it is said to persist as a functional organ in the adult. In other fishes, however, and in all higher forms the pronephros atrophies and becomes reduced to a few rudiments.[17]

[17] The objection may be raised that a purely embryonic organ
like the pronephros, which is functional in but few vertebrate
adults and which originates in vertebrate embryos only to
undergo atrophy, can have no other explanation than that of
“recapitulation.” The objection, however, fails to take into
account the possibility of the organ being serviceable to
the _embryo_, in which it may be a provisory solution of the
excretory problem and not a vestige of past ancestry.

(2) _The mesonephric system_: This consists of a collection of nephridial tubules called the mesonephros (Wolffian body). The tubules of the mesonephros do not develop any duct of their own, but utilize the posterior portion of the pronephric duct, the said tubules becoming secondarily connected with this duct in a region posterior to the pronephridia (tubules of the pronephros). The pronephric tubules together with the anterior portion of the pronephric duct then atrophy, while the persisting posterior portion of this duct receives the name of mesonephric or Wolffian duct. The duct in question still terminates in the cloaca, and serves, in the male, the combined function of a urinary and spermatic duct; but, in the female, a special oviduct (the Müllerian duct) is superadded because of the large size of the eggs to be transmitted, the Wolffian or mesonephric duct subserving only the urinary function. The mesonephros is functional in mammalian embryos, but atrophies and disappears coincidently with the development of the permanent kidney. The same is true of amniotic vertebrates generally, except that in the case of reptiles the mesonephros persists for a few months after hatching in the adult, the definitive kidney of the adult being reinforced during that interval by the still functional mesonephros. In anamniotic vertebrates, however, no separation exists between the mesonephros and the metanephros, the two forming one continuous structure, the opisthonephros, which acts as the functional kidney of the adult.

(3) _The metanephric system_: In the amniotic vertebrates the mesonephros and metanephros are distinct, the former being functional in embryos and in adult reptiles (for a few months after hatching), while the metanephros becomes the definitive kidney of the adult. The metanephros is a collection of nephridial tubules provided with a special urinary duct called the ureter, which empties into the bladder (not the cloaca). The Wolffian or mesonephric duct is retained as a sperm duct in the male (of amniotic vertebrates), but becomes vestigial in the female. Only a certain number of the nephridial tubules of the embryonic metanephros are taken over to form part of the permanent or adult kidney (in mammals, birds, and reptiles).

If, then, as we have previously observed, we follow Kerr in regarding the fish kidney, not as a simple mesonephros, but as an opisthonephros (_i.e._ a combination of mesonephros and metanephros), there is no warrant for interpreting the embryonic mesonephros of man and mammals generally as the fish-kidney stage. But waiving this consideration, and assuming, for the sake of argument, that the fish kidney is a perfect homologue of the human mesonephros, the mere fact of the adoption by the human embryo of a temporary solution of its excretory problem similar to the permanent solution of that problem adopted by the fish, would not, of itself, imply the common ancestry of men and fishes. Such a coincidence would be fully explicable as a case of convergent adaptation occurring in the interest of embryonic economy.

It is, indeed, a well-known fact that larval and embryonic organisms are often obliged to defer temporarily the construction of the more complex structures of adult life, and to improvise simpler substitutes for use until such a time as they have accumulated a sufficient reserve of energy and materials to complete the work of their more elaborate adult organization. The young starfish, for example, arising as it does from an egg but scantily supplied with yolk, is forced, from the very outset, to shift for itself, in coping with the food-getting problem. Under stress of this necessity, it economizes its slender resources by constructing the extremely simple digestive and motor apparatus characteristic of the larva in its bilaterally-symmetrical _Bipinnaria_ stage, and postponing the development of the radially-symmetrical structure characteristic of the adult stage, until it has stored up the wherewithal to complete its metamorphosis.

From this viewpoint, there is no difficulty in understanding why _temporary_ solutions of the excretory problem should precede the _definitive_ solution of this problem in mammalian embryos. The problem of excretion is urgent from the outset, and its demands increase with the growth of the embryo. It is only natural, then, that a series of improvised structures should be resorted to, in a case of this kind; and, since these temporary solutions of the excretory problem must, of necessity, be as simple as possible, it should not be in the least surprising to find them coinciding with the permanent solutions adopted by inferior organisms less complexly organized than the mammals. Hence the bare fact of resemblance between the transitory embryonic kidney of a mammal and the permanent adult kidney of a fish would have no atavistic significance. We know of innumerable cases in which an identical adaptation occurs in genetically unrelated organisms. The cephalopod mollusc _Nautilus_, for example, solves the problem of light-perception in the identical manner in which it is solved by the vertebrates. This mollusc has the perfect vertebrate type of eye, including the lens and all other parts down to the minutest detail. The fact, however, that the mollusc solves its problem by using the stereotyped solution found in vertebrates rather than by developing a compound eye analogous to the type found among arthropods, is wholly destitute of genetic significance. In fact, the genetic interpretation is positively rejected by the evolutionists, who interpret the occurrence of similar eyes in molluscs and vertebrates as an instance of “accidental convergence.” Even assuming, then, what Kerr denies, namely, a perfect parallelism between the mesonephros of the human embryo and the permanent kidney of an adult fish, the alleged fact that the human embryo temporarily adopts the same type of solution for its excretory problem as the one permanently employed by the fish would not in itself be a proof of our descent from a fish-like ancestor.

In fact, not only is embryological homology of no greater value than adult homology as an argument for evolution, but it is, on the contrary, considerably inferior to the latter, as regards cogency. _Differentiation_ pertains to the final or _adult_ stage of organisms. Embryonic structures, inasmuch as they are undeveloped and undifferentiated, present for that very reason an appearance of crude and superficial similarity. “Most of what is generally ascribed to the action of the so-called biogenetic law,” says T. Garbowski, “is erroneously ascribed to it, since all things that are undeveloped and incomplete must be more or less alike.” (“Morphogenetische Studien,” Jena, 1903.) When we consider the fact that the metazoa have all a similar unicellular origin, are subject to uniform morphogenetic laws, and are frequently exposed to analogous environmental conditions demanding similar adaptations, it is not at all surprising that they should present many points of resemblance (both in their embryonic and their adult morphology) which are not referable to any particular line of descent. At all events, these resemblances are far too general in their extension to enable us to specify the type of ancestor responsible therefor. More especially is this true of embryological homologies, which are practically valueless as basis for reconstructing the phylogeny of any type. “That certain phenomena,” says Oskar Hertwig, “recur with great regularity and uniformity in the development of different species of animals, is due chiefly to the fact that under all circumstances they supply the necessary condition under which alone the next higher stage in ontogeny (embryological development) can be produced.” (“Allgemeine Biologie,” 1906, p. 595.) The same author, therefore, proposes to revamp Haeckel’s “biogenetisches Grundgesetz” as follows: “We must leave out the words ‘recapitulation of forms of extinct ancestors’ and substitute for them ‘repetition of forms regularly occurring in organic development, and advancing from the simple to the more complex.’” (_Op. cit._, p. 593.)

Finally, when applied to the problem of man’s alleged genetic connection with the ape, the biogenetic principle proves the exact reverse of what the Darwinians desire; for as a matter of fact the young apes resemble man much more closely in the shape of the skull and facial features than do the adult animals. Inasmuch, therefore, as the ape, in its earlier development, reveals a more marked resemblance to man than is present in its later stages, it follows, according to the “biogenetic law,” that man is the ancestor of the ape. This, however, is inadmissible, seeing that the ape is by no means a more recent type than man. Consequently, as applied to man, the Haeckelian principle leads to a preposterous conclusion, and thereby manifests its worthlessness as a clue to phylogeny. Julius Kollmann, it is true, gives serious attention to this likeness between young apes and men, and makes it the basis of his scheme of human evolution. “Kollmann,” says Dwight, “starts from the fact that the head of a young ape is very much more like that of a child than the head of an old ape is like that of a man. He holds that the likeness of the skull of a very young ape is so great that there must be a family relationship. He believes that some differentiation, some favorable variation, must occur in the body of the mother and so a somewhat higher skull is transmitted to the offspring and is perpetuated. Concerning which Kohlbrugge remarks that ‘thus the first men were developed, not from the adult, but from the embryonic forms of the anthropoids whose more favorable form of skull they managed to preserve in further growth.’ ... Schwalbe makes the telling criticism of these views of Kollmann that much the same thing might be said of the heads of embryonic animals in general that is said of those of apes, and that thus mammals might be said to have come from a more man-like ancestor.” (_Op. cit._, pp. 186, 187.) All of which goes to show that the “biogenetic law” is more misleading than helpful in settling the question of human phylogeny.

§ 3. Rudimentary Organs

Darwin attached great importance to the existence in man of so-called rudimentary organs, which he regarded as convincing evidence of man’s descent from the lower forms of animal life. Nineteenth century science, being ignorant of the functional purpose served by many organs, arbitrarily pronounced them to be useless organs, and chose, in consequence, to regard them all as the atrophied and (wholly or partially) functionless remnants of organs that were formerly developed and fully functional in remote ancestors of the race. Darwin borrowed this argument from Lamarck. It may be stated thus: Undeveloped and functionless organs are atrophied organs. But atrophy is the result of disuse. Now disuse presupposes former use. Consequently, rudimentary organs were at one time developed and functioning, viz. in the remote ancestors of the race. Since, therefore, these selfsame organs are developed and functional in the lower forms of life, it follows that the higher forms, in which these organs are reduced and functionless, are descended from forms similar to those in which said organs are developed and fully functional.

This argument, however, fairly bristles with assumptions that are not only wholly unwarranted, but utterly at variance with actual facts. In the first place, it wrongly assumes that all reduced organs are functionless, and, conversely, that all functionless organs are atrophied or reduced. Facts, however, prove the contrary; for we find frequent instances of reduced organs which function, and, _vice versa_, of well-developed organs which are functionless. The tail, for example, in cats, dogs, and certain Catarrhine monkeys, though it discharges neither the prehensile function that makes it useful in the Platyrrhine monkey, nor the protective function that makes it useful to horses and cattle in warding off flies, is, nevertheless, despite its inutility or absence of function, a quite fully developed organ. Conversely, the reduced or undeveloped fin-like wings of the penguin are by no means functionless, since they enable this bird to swim through the water with great facility.

To save his argument from this antagonism of the facts, Darwin resorts to the ingenious expedient of distinguishing between _rudimentary_ organs and _nascent_ organs. Rudimentary organs are undeveloped organs, which are wholly, or partially, useless. They have had a past, but have no future. Nascent organs, on the contrary, are undeveloped organs, which “are of high service to their possessors” (“Descent of Man,” ch. I, p. 28, 2nd ed.). They “are capable of further development” (_ibidem_), and have, therefore, a future before them. He gives the following examples of rudimentary organs: “Rudimentary organs ... are either quite useless, such as teeth which never cut through the gums, or almost useless, such as the wings of an ostrich, which serve merely as sails.” (“Origin of Species,” 6th ed., ch. XIV, p. 469.) As an example of a nascent organ, he gives the mammary glands of the oviparous Duckbill: “The mammary glands of the Ornithorhynchus may be considered, in comparison with the udders of a cow, as in a nascent condition.” (_Op. cit._, ch. XIV, p. 470.)

Darwin admits that it is hard to apply this distinction in the concrete: “It is, however, often difficult to distinguish between rudimentary and nascent organs; for we can judge only by analogy whether a part is capable of further development, in which case alone it deserves to be called nascent.” (_Op. cit._, ch. XIV, p. 469.) For Darwin “judging by analogy” meant judging on the assumption that evolution has really taken place; for he describes rudimentary organs as being “of such slight service that we can hardly suppose that they were developed under the conditions which now exist.” (“Descent of Man,” ch. I, p. 29.)

He is somewhat perplexed about applying this distinction to the penguin: “The wing of the penguin,” he admits, “is of high service, acting as a fin; it may, therefore, represent the nascent state: not that I believe this to be the case; it is more probably a reduced organ, modified for a new function.” (“Origin of Species,” 6th ed., ch. XIV, pp. 469, 470.) In other words, there is scarcely any objective consideration by which the validity of this distinction can be checked up in practice. Like homology and convergence, like palingenesis and cænogensis, the distinction between rudimentary and nascent organs is a convenient device, which can be arbitrarily manipulated according to the necessities of a preconceived theory. It is “scientific” sanction for the privilege of blowing hot and cold with the same breath.

The assumption that atrophy and reduction are the inevitable consequence of disuse, or diminution of use, in so far as this decreases the flow of nourishing blood to unexercised parts, is certainly erroneous. Yet Darwin made it the premise of his argument from so-called rudimentary organs. “The term ‘disuse’ does not relate,” he informs us, “merely to lessened action of muscles, but includes a diminished flow of blood to the part or organ, from being subjected to fewer alternations of pressure, or from being in any way less habitually active.” (“Origin of Species,” 6th ed., p. 469.) As a matter of fact, however, we have many instances in which use has failed to develop and disuse to reduce organs in certain types of animals. As an example in point, we may cite the case of right-handedness among human beings. From time immemorial, the generality of mankind have consistently used the right hand in preference to the left, without any atrophy or reduction of the left hand, or over-development of the right hand, resulting from this racial practice. “The superiority of one hand,” says G. Elliot Smith, “is as old as mankind.” (Smithson. Inst. Rpt. for 1912, p. 570.) It is true that only about 6,000 years of human existence are known to history, but, if one accepts the most conservative estimates of glaciologists, man has had a much longer prehistory, the lowest estimates for the age of man being approximately 30,000 years. Thus W. J. Sollas tells us that the Glacial period, in which man first appeared, came to an end about 7,000 years ago, and that the men buried at Chapelle-aux-Saints in France lived about 25,000 years ago. His figures agree with those of C. F. Wright, who bases his calculations on the Niagara Gorge. The Niagara River is one of the postglacial streams, and the time required to cut its gorge has been calculated as 7,000 years. Gerard De Geer, the Swedish scientist, gives 20,000 years ago as the end of glacial and the commencement of recent or postglacial time. He bases his estimates on the sediments of the Yoldia Sea in Sweden. His method consists in the actual counting of certain seasonally-laminated clay layers, presumably left behind by the receding ice sheet of the continental glacier. The melting is registered by annual deposition, in which the thinner layers of finer sand from the winter flows alternate with thicker layers of coarser material from the summer flows. In warm years, the layers are thicker, in colder years they are thinner, so that these laminated Pleistocene clays constitute a thermographic as well as a chronological record. De Geer began his study of Pleistocene clays in 1878, and in 1920 he led an expedition to the United States, for the purpose of extending his researches. (Cf. _Science_, Sept. 24, 1920, pp. 284-286.) At that time, he claimed to have worked out the chronology of the past 12,000 years. His figure of 20,000 years for postglacial time, while very displeasing to that reckless foe of scientific caution and conservatism, Henry Fairfield Osborn, tallies very well with the estimates of Sollas and Wright. H. Obermaier, basing his computation on Croll’s theory that glaciation is caused by variations in the eccentricity of the earth’s orbit about the sun, which would bring about protracted winters in the hemisphere having winter, when the earth was farthest from the sun (with consequent accumulation of ice), gives 30,000 years ago as the date of the first appearance of man on earth. Father Hugues Obermaier, it may be noted, like Abbé Henri Breuil, is one of the foremost authorities on the subject of prehistoric Man. Both are Catholic priests.

All such computations of the age of man are, of course, uncertain and theoretical. Evolutionists calculate it in hundreds of thousands, and even millions, of years. After giving such a table of recklessly tremendous figures, Osborn has the hypocritical meticulosity to add that, for the sake of _precision_ (save the mark!) the nineteen hundred and some odd years of the Christian era should be added to his figures. But, even according to the most conservative scientific estimates, as we have seen, man is said to have been in existence for 30,000 years, and the prevalence of right-handedness among men is as old as the human race. One would expect, then, to find modern man equipped with a gigantic right arm and a dwarfed left arm. In other words, man should exhibit a condition comparable to that of a lobster, which has one large and one small chela. Yet, in spite of the fact that the comparative inaction of the human left hand is supposed to have endured throughout a period of, at least, 30,000 years, this state of affairs has not resulted in the faintest trace of atrophy or retrogression. Bones, muscles, tendons, ligaments, nerves, blood vessels, and all parts are of equal size in both arms and both hands. Excessive exercise may overdevelop the musculature of the right arm, but this is an individual and acquired adaptation, which is never transmitted to the offspring, _e.g._ the child of a blacksmith does not inherit the muscular hypertrophy of his father. Disuse, therefore, has not the efficacy which Lamarck and Darwin ascribed to it.

In fine, it must be recognized, once for all, that organisms are not-molded on a Lamarckian basis of use, nor yet on a Darwinian basis of selected utility. Expediency, in other words, is not the sole governing principle of the organic world. Neither instinctive habitude nor the struggle for existence succeeds in forcing structural adaptation of a predictable nature. Animals with different organic structure have the same instincts, _e.g._ monkeys with, and without, prehensile tails alike dwell in trees; while animals having the same organic structure may have different instincts, _e.g._ the rabbit, which burrows, and the hare, which does not, are practically identical in anatomical structure. Again, some animals are highly specialized for a function, which other animals perform without specialized organs, as is instanced in the case of moles, which possess a special burrowing apparatus, and prairie-dogs, which burrow without a specialized apparatus. Any system of evolution, which ignores the internal or hereditary factors of organic life and strives to explain all in terms of the environmental factors, encounters an insuperable obstacle in this remorseless resistance of conflicting facts.

Another flaw in the Darwinian argument from rudimentary organs is that it confounds, in many cases, _apparent_, with _real_ inutility (or absence of function). Darwin and his followers frequently argued out of their ignorance, and falsely concluded that an organ was destitute of a function, merely because _they_ had failed to discover its utility. Large numbers, accordingly, of highly serviceable organs were catalogued as vestigial or rudimentary, simply because nineteenth century science did not comprehend their indubitable utility. With the advance of present-day physiology, this list of “useless organs” is being rapidly depleted, so that the scientific days of the rudimentary organ appear to be numbered. At any rate, in arbitrarily pronouncing many important and functioning organs to be useless vestiges of a former stage in the history of the race, the Darwinians were not the friends of Science, but rather its reactionary enemies, inasmuch as they sought to discourage further investigation by their dogmatic decision that there was no function to be found. In so doing, however, they were merely exploiting the ignorance of their times in the interest of a preconceived theory, which whetted their appetite for discovering, at all costs, the presence in man of functionless organs.

Their anxiety in this direction led them to consider the whole group of organs constituting a most important regulatory and coördinative system in man and other vertebrates as so many useless vestigial organs. This system is called the _cryptorhetic system_ and is made of internally-secreting, ductless glands, now called _endocrine glands_. These glands generate and instill into the blood stream certain chemical substances called _hormones_, which, diffusing in the blood, produce immediate stimulatory, and remote metabolic effects on special organs distant from the endocrine gland, in which the particular hormone is elaborated. As examples of such endocrine glands, we may mention the pineal gland (epiphysis), the pituitary body (hypophysis), the thyroid glands, the parathyroids, the islelets of Langerhans, the adrenal bodies (suprarenal capsules), and the interstitial cells of the gonads. The importance of these alleged useless organs is now known to be paramount. Death, for instance, will immediately ensue in man and other animals, upon extirpation of the adrenal bodies.

The late Robert Wiedersheim, it will be remembered, declared the pineal gland or epiphysis to be the surviving vestige of a “third eye” inherited from a former ancestor, in whom it opened between the parietal bones of the skull, like the median or _pineal eye_ of certain lizards, the socket of which is the parietal foramen formed in the interparietal suture. If the argument is based on homology alone, then the coincidence in position between the human epiphysis and the median optic nerve of the lizards in question has the ordinary force of the evolutionary argument from homology. But when one attempts to reduce the epiphysis to the status of a useless vestigial rudiment, he is in open conflict with facts; for the pineal body is, in reality, an endocrine gland generating and dispersing a hormone, which is very important for the regulation of growth in general and of sexual development in particular. Hence this tiny organ in the diencephalic roof, no larger than a grain of wheat, is not a functionless rudiment, but an important functioning organ of the cryptorhetic system. We have no ground, therefore, on this score for inferring that our pineal gland functioned in former ancestors as a median eye comparable to that of the cyclops Polyphemus of Homeric fame.

In like manner, the pituitary body or hypophysis, which in man is a small organ about the size of a cherry, situated at the base of the brain, buried in the floor of the skull, and lying just behind the optic chiasma, was formerly rated as a rudimentary organ. It was, in fact, regarded as the vestigial remnant of a former connection between the neural and alimentary canals, reminiscent of the invertebrate stage. “The phylogenetic explanation of this organ generally accepted,” says Albert P. Mathews, “is that formerly the neural canal connected at this point with the alimentary canal. A probable and almost the only explanation of this, though an explanation almost universally rejected by zoölogists, is that of Gaskell, who has maintained that the vertebrate alimentary canal is a new structure, and that the old invertebrate canal is the present neural canal. The infundibulum, on this view, would correspond to the old invertebrate œsophagus, the ventricle of the thalamus to the invertebrate stomach, and the canal originally connected posteriorly with the anus. The anterior lobe of the pituitary body could then correspond to some glandular adjunct of the invertebrate canal, and the nervous part to a portion of the original circumœsophageal nervous ring of the invertebrates.” (“Physiological Chemistry,” 2nd ed., 1916, pp. 641, 642.)