142 HOUSEHOLD BACTERIOLOGY 



Now, the cell so runs the theory finding itself 

 deprived of its food, produces a new and increased 

 amount of this food-seizing substance. In fact, in 

 accordance with a well-known law in pathology, it 

 produces such a surplus of this substance that it is 

 cast off into the body fluid. 



But this food-seizing substance, now produced in 

 superabundance and cast off, is still capable of uniting 

 with the poison which is circulating in the body fluids. 

 This it does, and as molecule by molecule the poison 

 forms the new chemical union it is neutralized and 

 so prevented from coming in contact with the cells, 

 where alone it can do harm. This is antitoxic im- 

 munity. 



Now, if more of this stuff is given off by the cells 

 in the emergency than is necessary to render all the 

 poison harmless, the excess in the body fluid remains 

 there as unused antitoxin. This is the condition of 

 the immuned horse. His cells have produced more 

 antitoxin than is necessary to protect himself, and 

 we draw off some of it in the blood and^ use it to 

 save the child. 



Thus we see that this curious protective process 

 is not an incredible anomaly, but that the body cells 

 have availed themselves in an emergency as protective 

 agencies of those capacities which under normal con- 

 ditions they use in the assimilation of their food. 



This power of the body to protect itself against the 

 poisonous products of bacterial life may be exerted 



