Page:Catholic Encyclopedia, volume 5.djvu/746

 EVOLUTION

668

EVOLUTION

The sponge-like structure in the femur of man and anthropoid exhibits considerable difference, so that it could be established by means of radiogrammes whether the femur was that of an upright walking ., it was possible to prove the Xeandertal and Spy femora to be human. The foot of man is, moreover, very char- acteristic. It is not furnished with a thumb that can be bent across the whole mem- ber, and hence it does not represent a typical prehensile organ, as is the case with the hind feet of the monkey. In general, each bone and organ of man could in some sense lip styled ape-like, but in no case does this similarity go so far that the form peculiar to man would pass over into the form which is peculiar to the ape. This conclusion is con- firmed by the fact that, according to Ranke and Weisbach, all the efforts to discover a series of liodily formations which would lead from the most apelike savages t IP t he least apelike Caucasians liave till now resulted in uittT failure, since the apelike i> inns of organs actually found ill some individuals are not cmifined to a single race or nation, but are distributed throughout all of them. Tailed ape-men, in the proper sense I if t he word, have no existence. If sometimes tail-like append- ages occur, the}' .are genuine deformities, pathological rem- nants of the individual's em- bryonic life. Cretins and mi- crocepliali are likewise pathological cases. The theory that such were the ancestors of the hum.an species is certainly excluded by the fact that they are un- able to procure independently the necessary means of existence.

(3) "Blood Relntionship" between Man and the An- thropoid. — In lltOO Friedental thought that he was able to prove the kinship of man and the anthropoid biochemically by showing, first, that the transfusion of human blood-serum into the chimpanzee was not followed by any signs of lilood-poisoning, as usually happens on the introduction of foreign blood, and, secondly, that human serum did not produce a reac- tion when introduced into a solution of the blood of the orang and gibbon, while on the other hand it dis- solved the l)lood corpuscles of the lower apes. A little later Xutall and others proved that anti-sera exercised an opposite effect. An "anti-man-serura" was pre- pared by injecting subcutaneously sterile human serum into a rabbit till the animal became immune to poisoning from the foreign blood-serum. The "anti- man-serum" of r.abbit-blood thus prepared gave a precipitate with tlic bliiod-serum of man or of an ani- mal with chemically similar blood, for instance an- thropoids, but not with the serum of chemically dilTer- eut blood. The force of the argument lies, therefore, in this, that the chemical reaction obtained seems to be on the whole proportional to the degree of their chemical affinity.

What follows from these facts? — Only this, that the bloofl of man is chemically similar to that of the an- thropoifls; but it does not follow that this chemical similarity must be attributed to any kinship of race.

Skeleton of Frenchman

The mistake arises from the confusion of the ideas " similarity of blood " and " blood-relationship " in the genealogical sense of the term; otherwise it would be at once perceived that the fact of chemical similarity of blood is of no more importance for the theory of evolution than any other fact of comparative mor- phology or physiology.

(4) Rudimentary Organs. — One of the special argu- ments commonly cited in favour of the evolution the- ory is based on the frequent occurrence of rudimentary structures in organisms. As examples we may men- tion the following; Pythons and boas possess vestiges of hind legs and of a pelvis separated from the verte- bral column. — The slow-worm is without external limbs, and yet possesses the shoulder-girdle and the pelvis, as well as a slightly developed breast-bone. — The ostrich has merely stunted wing-bones, while the nearly extinct kiwi (apteryx) of New Zealand has only extremely small stumps of wings, which are clothed with hair-like feathers. — The gigantic birds of New Zealand which became extinct in past ages were en- tirely wingless. — Well worthy of note, also, are the rudimentary organs of the whale (Cetacea), since of the hind limbs only a few minute bones remain, and these are considerec-1 to be the pelvic bones, while the Green- land whale (Bahena mysticetus) also possesses thigh and leg bones. The bones of the fore-limbs are not movable independently of one another, being bound together by means of tendons — .Other remarkable vestigial structures are the teeth of the Arctic right whale, which never penetrate the gums and are reab- sorbed before birth, the upper teeth of the ox, the milk teeth and the eyes of the mole. The deep sea fish, like the Barathro- nus, have instead of eyes " two golden metallic concave mirrors" (Chun). — Nor is man devoid of rudimentary or- gans. Wiedersheim mentions no fewer than one hundred But of these only a few are genuine. The vermiform aj)- pendix may serve as an example, though according to recent research it is not entirely function- less. Its length os- cillates between J cm. and 23 cm., while its breadtli and external form vary exceedingly. Probable reasons for its partially ru- dimentary charac- ter are, besides its extreme variability, especially two facts in particular: the length of the organ compared with that of the large inte.s- tineisas 1:10 in the emliryo, and as 1: 20"in the adult; .seoondly, in 32 per cent of all cases among adults of over twenty years of age the ap- pendix is found to be closed.

Do such rudimentary organs furnish us with an ac- ceptable proof for the theory of evolution?— It is to be admitted that in many instances the organs were

r $

Skeleton of Orang-Utanq