SPECIAL CREATION OR DERIVATION? 



sented in Professor Agassiz's " Essay on Classi- 

 fication " went far toward producing conviction 

 before the publication of Mr. Darwin's work on 

 the " Origin of Species," where the significance 

 of such facts is clearly pointed out and strongly 

 insisted upon. 



II. An equally powerful argument is fur- 

 nished by the embryonic development of organ- 

 isms. As Von Baer long ago pointed out, the 

 germs of all animals are at the outset exactly 

 like each other ; but in the process of develop- 

 ment each germ acquires first the differential 

 characteristics of the sub-kingdom to which it 

 belongs, then successively the characteristics of 

 its class, order, family, genus, species, and race. 

 For example the germ-cell of a man is not only- 

 indistinguishable from the germ-cell of a dog, a 

 chicken, or a tortoise, but it is like the adult 

 form of an amoeba or a protococcus, which are 

 nothing but simple cells. Four weeks after con- 

 ception the embryos of the man and the dog 

 can hardly be distinguished from each other, 

 but have become perceptibly different from the 

 corresponding embryos of the chicken and tor- 

 toise. At eight weeks a few points of difference 

 between the dog and the man become percep- 

 tible ; the tail is shorter in the human embrvo, 

 and the cerebrum and cerebellum have become 

 larger, relatively to the corpora quadrigemina, 

 than in the embryo of the dog ; but these dif- 



4 395 



