ANAPHYLAXIS AND IMMUNITY 93 



the eventual development by the cells of the organism of further 

 enzymes, which disintegrate the poisonous moiety of the protein 

 disintegration products, and so carry on the degradation of the 

 foreign protein to a harmless stage ; which break up the associa- 

 tion of radicles still further, so that now they are converted into 

 more elementary constituents which, instead of disturbing the 

 cell activities, can, perchance, be utilized as food-stuffs. As 

 my colleague Dr. Fraser Gurd 1 has shown, in the immunized 

 animal the earlier enzymes are not replaced, they are still active 

 and abundant, but evidently after they have broken down the 

 specific protein, with the liberation of the poisonous substance, 

 this is immediately acted upon by the new specific enzymes and 

 rendered innocuous. 2 



(vi.) Cell and Tissue Differentiation: Ontogeny. With this 

 clear indication, therefore, before us of the way in which the 

 cell substance can become modified and adapt itself according 

 to need, it is not necessary, with Weismann, to postulate the 

 existence of two orders of living matter, germ plasm and somato- 

 plasm. It sufiices to hold that there is one common biophoric 

 material, or at most biophoric material in part derived from one, 

 in part from the other parent, and to recognize that as the fertil- 

 ized cell divides and redivides and the resultant cells find them- 

 selves in different relationships, so do they become modified 

 and differentiated, giving origin to the various tissues, the 

 eventual germ cells being so developed and so placed that they 

 are exposed to the minimal amount of differentiation. 



If embryogeny or, more exactly, ontogeny the development 

 of the individual is a recapitulation of the phylogeny of the 

 evolution of the race it is this not as an historical reminiscence 

 and nothing more. It is this only so far as it is a necessity, 

 only so far as-, for the unfolding and elaboration of the cell 

 structure of the various tissues up to the stage in which the 

 adult of a particular species will find itself in equilibrium with 

 its surroundings, the biophores distributed to those cells must, 

 of necessity, in the course of their growth and multiplication, 

 pass through a particular succession of equilibrations, of modifica- 

 tions, of accretions and losses. Where a given modification can 



1 Amer. Jour. Trop. Dis. and Prevent. Med. i., 1914, 776, and Jour. Med. 

 Ees. xxxi., 1914, 205. 



8 For a fuller study of these matters see the paper upon " Parenteral Diges- 

 tion " in Pt. II. Chap. IX. 



