42 The Unity of the Organism 



curity in something or other to which the word genesis 

 can be attached, but which can yet be conceived as not sub- 

 ject to transformation, is everywhere hostile in a funda- 

 mental sense to the descent theory. 



The latest manifestation of this hostility is the gene or 

 factor theory of the ultra-Mendelians among present-day 

 geneticists. The gene as conceived in the genotype theory 

 turns out on close inspection to be still another something- 

 or-other, which though not itself transformable can explain 

 transformation in something else, and which has been ap- 

 pealed to by generation after generation of elemental- 

 minded theorizers about the origin of living beings, from the 

 ancient Grecian period at least. Jennings, one of the ablest 

 of the experimental geneticists, and one who has a genuine 

 regard for the visible as contrasted with the invisible and 

 hypothetical data of organic genesis, has lately pointed out 

 the essentially non-evolutionary character of the genotype 

 theory. "The whole conception," he rightly says, "is in 

 its essential nature static; alteration does not fit into the 

 scheme." 8 We shall have occasion to consider this new 

 phase of the non-transformism in other connections. Our 

 purpose in referring to it here is merely to point out where 

 it belongs in the general scheme of genetic theorizing when 

 this scheme is viewed historically. Biology at present needs 

 few things more sorely than a system of reasoning which 

 shall not beget in students the mental habit of allowing re- 

 condite concepts and postulates and strange words to cast 

 every-day, familiar facts into outer darkness. One of the 

 most obvious and indubitable facts about all organic de- 

 velopment is transformation. The development of a chick 

 from a hen's egg is accomplished not merely by a great in- 

 crease in size, but by the profoundest sort of transforma- 

 tion, this being deployed, as one may say, through a long 

 series of stages grading insensibly one into another. And 

 so with every other ontogeny, animal ontogeny especially. 



