WHA T IS DA R WINISM ? 171 



into a fish and the other into a bird. Why is 

 this ? There is no physical force, whether 

 light, heat, electricity, or anything else, which 

 makes the slightest approximation to account- 

 ing for that fact. To say, as Stuart Mill would 

 say, that it is an ultimate fact, and needs no ex- 

 planation, is to say that there may be an effect 

 without an adequate cause. The venerable R. 

 E. Yon Baer, the first naturalist in Russia, of 

 whom Agassiz speaks in terms of such affection- 

 ate veneration in the " Atlantic Monthly " for 

 January, 1874, has written a volume dated 

 Dorpat, 1873, and entitled "Zum Streit liber 

 den Darwinismus." In that volume, as we 

 learn from a German periodical, the author 

 says : " The Darwinians lay great stress on 

 heredity ; but what is the law of heredity but 

 a determination of something future ? Is it not 

 in its nature in the highest degree Ideologi- 

 cal ? Indeed, is not the whole faculty of re- 

 production intended to introduce a new life- 

 process? When a man looks at a dissected 

 insect and examines its strings of eggs, and 

 asks, Whence are they ? the naturalist of our 

 day has no answer to give, but that they were 

 of necessity gradually produced by the changes 

 in matter. When it is further asked, Why are 



