40 DEFENSIVE FEKMKNTS OF THE ANIMAL ORGANISM 



plasma ? Is it deprived of the possibility of defend- 

 ing itself against such substances, or have the 

 cells of the body also, excluding those of the 

 intestines, retained the capacity of attacking com- 

 plicated substances which are out of harmony with the. 

 organism, and of reducing them by profound decom- 

 position to indifferent particles, which the cells may 

 use for the construction of new material, or else as a 

 source of energy ? 



To solve this problem, in a satisfactory manner, 

 preliminary experiments on a very large scale were 

 required. First of all, it was necessary to ascertain 

 in what manner the individual cells of the body use 

 up the nourishment which is normally brought to 

 them by the blood. Does the individual cell decom- 

 pose the complicated nutritive material directly into 

 its encl-products, or does it always disintegrate them 

 first into simpler fragments, which are then reduced 

 by successive stages, until finally the whole of the 

 stored energy which the organism is capable of 

 setting free is at the disposal of the cell, and the 

 final products of the decomposition appear? All 

 experiments that have hitherto been carried out in 

 this direction lead us, as we pointed out at the 

 beginning, to the idea that each separate cell of the 

 body in general, with very few exceptions, disposes 

 of the same, or of similar, ferments as those 

 secreted by the digestive glands into the intestinal 



