COMMUNICABLE DISEASES 373 



In a general way it may be stated that any cause, factor or influence, 

 which tends to lower the vitality, predisposes to disease. Individuals with 

 a well-balanced physical and mental development are less liable to disease, 

 and when attacked are more apt to recover, than those individuals who 

 have a poor physical development. Undue abstinence is as harmful as 

 over-indulgence. The ascetic is as pathologic as the gouty gourmand. 



FIG. 89. FIG. 90. 



FIG. 89. Bacillus mallei, the cause of glanders in horses. This disease can be trans- 

 mitted to man where it causes symptoms of a suppurative infection of the lymphatic 

 glands. Mallein, which is used in testing horses for glanders, consists of the filtrate 

 (Berkeield filter) of dead cultures (glycerin bouillon) of the bacillus. A positive malleiu 

 reaction consists in a rise in temperature and local swelling. The dose is i c.c. 



FIG. 90. Bacillus tetani, an anaerobic spore-bearing bacillus, the cause of tetanus or 

 lockjaw. This bacillus is found in soils and may infect abrasions, cuts and wounds. 

 Treatment with tetanic antitoxin is successful if begun before the symptoms develop. 

 The best time to administer the antitoxin is at the time the injury is received. 



FIG. 91. A spore-bearing bacillus stained with methyl blue leaving the spores un- 

 stained. Fortunately most of the bacilli pathogenic to man do not bear spores. 



Irrational diet, drink and food fads, sooner or later leave their pernicious 

 effects upon the system and predispose to certain diseases. Overeating 

 is as objectionable as starvation. Lack of adequate physical exercise has 

 its evil effects as does also over-exertion. Trained or professional athletes 

 are not long lived, many are hopelessly afflicted with enlarged and weak- 

 ened heart and arteries (aneurism). Pernicious habits of all kinds indicate 



