THE ORIGIN OF THE HUMAN BODY 305 



sion to type; anomalous mammary glands may appear upon 

 the median line, upon the deltoid, and even upon the knee, 

 regions far-distant from the 'milk-line.' So with regard to 

 the postauricular muscles we must say that according to the 

 laws of Darwinism the cases of anomalous development are 

 not interpretable as reversions to type. All these features are 

 not phylogenetic reminiscences, but anomalies of develop- 

 ment, of such a nature that, if we should wish to make use 

 of them for establishing the line of human descent, we would 

 have to say that man descends from the swine, from the soli- 

 peds and even from the cetaceans, returning, namely, to the 

 old conception of lineal descent, that is, to Buffon's idea of 

 the concatenation of creatures." ("Teorie e critiche nella mo- 

 derna biologia," 1906.) 



Darwin's doctrine, however, on the origin and significance 

 of rudimentary organs has been damaged by genetic analysis 

 in a yet more serious fashion. In fact, with the discovery that 

 anomalous suppression and anomalous duplication of organs 

 may result from factorial mutation, this Darwinian concep- 

 tion received what is tantamount to its deathblow. Darwin, 

 it will be remembered, was convinced that the regression of 

 organs was brought about by "increased disuse controlled by 

 natural selection." (Cf. "Origin of Species," 6th ed., ch. V.) 

 Such phenomena, he thought, as the suppression of wings in 

 the Apteryx and the reduction of wings in running birds, arose 

 from their "inhabiting ocean islands," where they "have not 

 been exposed to the attacks of beasts, and consequently lost 

 the power of using their wings for flight." ("Descent of Man," 

 6th ed., ch. I, p. 32.) In some cases, he believed that disuse 

 and natural selection had cooperated ex aequo to produce 

 results of this nature, e.g. the reduction of the eyes in the mole 

 and in Ctenomys; for this reduction, he claims, has some 

 selection-value, inasmuch as reduction of the eyes, adhesion of 

 the lids, and covering with hair tends to protect the unused and 

 useless eye against inflammation. In other cases, however, 

 he is inclined to discount the idea that suppression of organs 



