8o 



first to the dignity of a truth also. Occasion 

 ally, not only two, but entire series of hypoth 

 eses thus become established truths. The 

 argument from the whalebone-whale is a bril 

 liant example of this. Father Wasmann says 

 of it: 



"As an example of this (the biogenetic prin 

 ciple), I may refer to the teeth which the em 

 bryos of the whalebone-whale still possess, al 

 though subsequently they degenerate into 



whalebone If we may compare with it 



the further fact that geology has ascertained, 

 viz., that the whalebone-whale only in the ter 

 tiary period succeeded to the toothed whale, 

 which may be regarded as its probable ances 

 tor, the conclusion is obvious. The whalebone- 

 whale is descended from an older toothed 

 whale, and the reason why, in the development 

 of the individual whalebone-whale, there is a 

 stage at which teeth appear, lies in the fact (!) 

 that the ancestors of the present whales passed 

 through this stage of development, and it re 

 mains up to a certain definite point in the 

 growth of the embryo." 



This is a splendid specimen of the 



