SAFEGUARDS OF THE BODY 
141 
on hand in our mysterious insides the latent power of 
protection against all the special forms of disease- 
producing bacteria which wander the earth? How 
does it fit into physiology? Or can we indeed create 
new protective powers in the stress of such varied 
accidents as new infections involve? 
We have seen that the diphtheria bacillus produces 
its deadly effects through a poison which it sets free 
as it grows in the body. In order to understand how 
this poison is rendered harmless, we must know how 
it damages the delicate body cells. So we must go 
back to the cell for a moment. These cells in the 
living body sit in their respective places, and as the 
nutrient fluids pass and bathe them, each of them 
being a powerful little chemical factory, they seize up¬ 
on whatever nutrient molecules they require, and out 
of these build up such new substances as they need in 
their business, whether this be self-nutrition, or the 
storage of energy, or the furnishing of special life- 
stuff for their neighbors. So each cell is armed with 
this power of forming chemical union with the food. 
But suppose something comes along in the body 
fluids with which the cell can and does form the same 
sort of chemical union, but which is not a food; on 
the contrary, damages the cell—that is, is poisonous 
„ or toxic for it. The cell suffers, of course—first, by 
the direct damage, and, second, by the loss of its 
food-securing capacity. The latter it has used up in 
uniting with the poison. 
