220 THEORETICAL BIOLOGY 



original subject itself. It would be merely the rule of a 

 phenomenon, giving us no information as to the origin of the 

 phenomenon and its sequel. 



The genesis of an organism, however, is not just a musical 

 phenomenon. In the process of shaping, the full-grown sub- 

 ject finally recovers in fuller degree those functions which it 

 had in a more primitive form in the beginning. 



THE CRITICAL POINT 



-^ I call the critical point that moment when the subject, on 

 completion of its shaping process, suddenly finds itself in 

 possession of a framework fully developed and capable of 

 functioning. 



In the majority of animals the critical point becomes 

 clearly apparent when the creature leaves the egg, or when 

 it is born. In other animals, through interposition of a larval 

 period, the critical point is not so obvious. This difference is 

 the result of external circumstances which govern the taking 

 up of food and the growth during the process of shaping. 



The functional activity of the developing animal never 

 ceases altogether. The foamy framework of the protoplasm 

 is involved in a continual metabolism, and for this it requires 

 a steady food-supply in order to make good the energy ex- 

 pended. The need for food becomes very intense on account 

 of the growth that accompanies the shaping. Nutriment is 

 furnished by a reserve supply accumulated in the germ, or 

 it is brought by the maternal organism, or it has to be got 

 by the animal itself. In the last case certain genes must 

 provide larval organs serving for food-capture ; then the 

 animal as a whole continues functionally active throughout 

 its development. When the food is furnished by reserve 

 substances or by the mother, provision is made by develop- 

 ment of special food-routes for the supply of nourishment 



