SECT. 3] AND ORGANISATION 557 



duties to subsidiary but competent officials. This possibility becomes 

 a probability when the apparently mysterious and arbitrary grouping 

 of characters is considered, colour x always going together with pollen- 

 shape jv and so on. 



In any case there is no need to load all the responsibility for the 

 adult skate and dogfish on to their genetic equipment; any more 

 than we need suppose the constitution of their eggs to differ simply 

 by the presence of two different entelechies, as Driesch would say 

 (see p. 22). It is true that in many respects the chemical constitution 

 of eggs is alike in different animals, but only when very broadly con- 

 sidered. We know that the provision of amino-acids is by no means 

 the same, and serological differences, which have so far only been 

 touched on by a few workers (see Section 19), are likely to be of 

 much importance. Riddle has also emphasised the importance of 

 the environmental factors in contributing to the final result of onto- 

 genesis, so the three principal sets of morphogenetic causes which 

 exact biologists at present accept are thus: 



(i) The genetic constitution of the egg-cell. 



(ii) The physico-chemical constitution of the egg's raw materials. 



(iii) The environment during ontogeny. 



Woodger observes that modern genetics owes a debt to the pre- 

 formation theory of the eighteenth century. The old theory identified 

 the "immanent factors" in the egg with the whole of the newly 

 separated individual, and imagined nothing but an increase in 

 volume. The modern theory identifies the immanent factors with 

 certain small bits of the individual, such bits being thought of as 

 related to the qualities of the individual as cause to effect. Woodger 

 considers that we shall get on better by sharply distinguishing 

 between genetics and embryology instead of by attempting to fuse 

 them, as is now the general aim, for he regards the formation of 

 parts as fundamentally or causally separate from the determination 

 of characters. I must refer those who are interested, to the original 

 discussion, but if we are not to treat parts as characters, an entirely 

 new conception of evolution will be required. 



The difficulty of fusing morphology and physico-chemical biology 

 is, in fact, very real, and Rignano's objections, though they are far 

 from insuperable, are not merely restatements of finite teleology. 

 They bring up the question of how any real epigenesis can take 



