THE LIVING ORGANISM 207 



diseases, that a brief outline of it may prove 

 interesting. When an alien organism has 

 invaded an animal and commenced to form 

 poisons from the nutrition supplied by its 

 host, there is always a reaction induced 

 against the infection. There are two modes 

 of combat, one by means of a vast number 

 of free-living cells in the blood-stream of the 

 host, which engulf and digest the bodies of 

 the attacking organism. In so digesting 

 these organisms, these disease-resisting cells 

 (called leucocytes) produce substances which 

 have the exactly opposite effects to the 

 toxins, and are called anti-bodies or antitoxins. 

 Secondly, other cells in the body, while they 

 do not engulf and swallow the foreign organism 

 join in producing anti-bodies, which weaken 

 and kill the invading organisms, and also 

 combine with and neutralize the toxins which 

 the organisms have produced, and by saturat- 

 ing these prevent them attacking the tissue 

 cells. 



It is such a struggle as this which sets a 

 date to the duration of all the acute infectious 

 diseases, and the more poisonous the products 

 of the invading organism, so much the 

 sharper and shorter the struggle. It is the 

 production of the anti-bodies in addition to 

 chemical charges induced in the body cells 



