4 INFECTIOUS AND PARASITIC DISEASES. 



disease and divers' paralysis — two well-recognized 

 affections, the result of physical agents. 



That diseases are often brought about 

 Chemical through chemical agents scarcely needs 

 Agents, illustration on account of the frequency 



of such cases being reported by the Press, 

 and the familiarity of the average person with the 

 dangerous character of many chemicals, notably the 

 poisons. Ptpmain poisoning, which comes from eating 

 various foods that have undergone a peculiar decom- 

 position; arsenical poisoning, numerous cases of which 

 were reported in London, England, a few years ago, 

 in which the arsenic was traced to the glucose in beer; 

 and painters' colic, or lead colic, a disease common in 

 those whose occupations bring them into close contact 

 with lead, are examples of diseases of chemic origin. 

 Indeed, among the causes of disease, the chemical 

 agents are by far the most numerous and the most 

 important, in as much as the majority of diseased 

 states are fundamentally, or coincidentally, of a chem- 

 ical nature. Most of the physical and mechanical 

 agencies, through the injuries they inflict on tissues, 

 are thereby transformed into chemical irritants, since 

 the resulting reactions follow largely as a result of the 

 absorption of dead and useless material. For example : 

 A person is severely burned, yet survives three days. 

 He does not die as a direct result of the physical agent, 

 fire, but from poisoning in one of the two ways; namely. 



