CHAPTER V 



DEFENSES OF THE BODY 



THE defensive methods of the body are inherent 

 in the organization of its cells and fluids, and we 

 cannot expect to fully understand them until physi- 

 ology can command more refined ways of investi- 

 gation than at present. Yet it may be said that 

 slowly, and with infinite patience, important knowl- 

 edge has been gained of the multitudinous ways in 

 which the human organism rids itself of the influences 

 that threaten it. Some of these ways have a simple 

 mechanical end, as when coagulation of the blood 

 sets in to stop bleeding from an artery a defense 

 necessary, not merely after an accidental cut, but 

 after the exposure of the blood vessels after child- 

 birth. This coagulation defense, so often called on 

 and so fundamental, is in reality but incompletely 

 understood despite the attention that has been 

 given it. A very different type of protection comes 

 from the almost universally distributed powers of 

 oxidation that prevail in the body cells. The 

 ability of the organism to break down larger into 

 smaller molecules of foodstuffs simultaneously with 

 the appropriation of oxygen is a primitive function, 

 continuously in operation for the purpose of utiliz- 



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