lOOLOGlCAL LABOil^IORY, i^cGPJ^W ijAU. 



CHAPTEK IV. 



OF ANIMAL NTJTEITION. 



Afteb what has been already said concerning the chemical and 

 anatomical constitution of animals and plants, nutrition in 

 general, and the nutrition of plants, it will be possible to 

 abridge considerably the general exposition of the phenomena 

 of nutrition amongst animals. In eilect, if nutrition is traced 

 back to its fundamental activities, that is to say, to assimilation 

 and dis-assimilation within a living matter, amorphous or figurate, 

 the principal phenomena are plainly similar in both kingdoms ; 

 and, even if we only consider certain rudimentary animal 

 oi^anisms, for example the gregarine, we can say that there ia 

 an identity of process, not certainly with that which takes 

 place in the superior plants, where there already exists a high 

 degree of differentiation in tissue and of division of labour, but 

 with the nutritive mode of purely cellular plants. In effect, 

 the dissimilarity between plants and animals decreases in pro- 

 portion as we compare the inferior types of the two kingdoms. 



Correctly speaking, we should rather compare the gregarine, a 

 parasitical animal without organic differentiation, to a mushroom. 

 In effect, as mushrooms live by assimilating the products of 

 decomposed organisms, and seem powerless to effect the chemical 

 synthesis of which complete plants are the agents, in the same 

 way the gregarine absorbs and assimilates direct in the intestines 

 of articulated animals and worms, where it lives upon the 

 complex organic substances which it would be incapable of 



