280 THE CASE AGAINST EVOLUTION 



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 an- 

 cestors. 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 de- 

 veloping 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 reser- 

 vation, of the anamniotic vertebrates (fishes and amphibi- 

 ans). ^'In many of the lower Vertebrates," says this author, 

 "there is no separation between the mesonephros and meta- 

 nephros, the two forming one continuous structure which acts 

 as the functional kidney. Such a type of renal organ con- 

 sisting of the series of tubules corresponding to mesonephros 

 together with metanephros may conveniently be termed the 

 opisthonephros." ("Textbook of Embryology," II — Vertebrata, 

 p. 22L) If we accept this view, it is not quite accurate to 

 regard the mesonephros in man as a homologue of the opistho- 

 nephros of a fish, seeing that the latter is composed not only 

 of mesonephridia (mesonephric tubules), but also of meta- 



