POISONING 189 



oxygen. The disease anemia is an expression of this con- 

 dition. 



Poisoning. — By far the greater number of ills to 

 which flesh is heir are the result of direct interference with 

 the metabolism of protoplasm through the agency of par- 

 ticular chemical substances which, because they affect 

 protoplasm in this manner, are known as poisons. 

 Poisonous substances are very common in nature, it being 

 a curious feature of plant metabolism that a great many 

 kinds of plants produce and store within some part of 

 their structure chemical substances which are harmful to 

 animal protoplasm. There are also a number of inorganic 

 or mineral compounds known that are poisonous to pro- 

 toplasm. Where the bodily disturbance is due to the 

 taking into the stomach of a known poisonous substance, 

 the condition is referred to as acute poisoning, and is not 

 ordinarily considered to be a disease. But if the poison is 

 introduced into the body as part of supposedly good food, 

 or is produced by any means within the body itself, it 

 then becomes a cause of disease. 



Disease Due to Mechanical Injury. — The effect 

 of mechanical injury, or of a burn, is to destroy some liv- 

 ing tissue. Obviously, the more severe the injury or the 

 burn the more such tissue is destroyed. Destroyed tissue 

 is in part sloughed off at the surface of the body, and in 

 part taken up and absorbed within the body. One of the 

 important medical discoveries of the Great War was that 

 the products absorbed into the body from injured tissues 

 are highly poisonous. Surgeons have long known of a con- 

 dition of collapse following severe injury, to which they 

 have given the name " wound shock. " It is now known 

 that the symptoms of wound shock are due to the poison- 

 ing of the body by the absorption of the decomposition 

 products of the injured tissues. It has also been shown 

 that the prolonged suffering and slowness of recovery in 

 cases of severe bums are due to the absorption into the 

 body of poisonous products from the burned areas. Great 



