DEFENSIVE FERMENTS OF THE ANIMAL ORGANISM 5 



energic contents of the original material, until finally 

 -at least, with carbohydrates and fats the whole 

 amount of contained energy is released. The cell 

 regulates its own metabolism down to the minutest 

 details. In the proper preparation of the material 

 to be decomposed, and in the gradual liberation 

 of the amount of energy required, lies the real impor- 

 tance of those substances formed by the cell, which 

 we at present comprise under the name of ferments. 



The ferments have yet another value for the cell, 

 in that they help it to regulate its own structure. 

 Not every product which is taken up by the cell 

 passes into its structure. Sometimes the decomposi- 

 tion must be carried on further; in other cases the 

 particles must be synthesized suitably for the pro- 

 duction of the necessary structural unit; after 

 which it sets about the recombination of all the 

 numerous constructive units, so as to form the 

 complicated characteristic structure of the cell. 

 Though w y e do not yet know the precise nature of 

 the ferments, yet their specific activities, and their 

 great importance in regard to cell metabolism and 

 cell structure, are well known. 



Without energy no cell can do work or produce 

 heat, and it is in energic metabolism that we find 

 a true picture of the functions of the cell. How the 

 cell procures the required energy, in what manner 

 it makes use of it, and so on, we can learn only by 



