LECTURE XXX. 



ANTHRAX.* 



History. — (Joe of the oldest diseases known to medical sci- 

 ence. 



Distribution. — Almost world wide. In the United States, 

 anthrax is sporadic in the North, East, and West; but in the 

 South, more particularly in parts of the Lower Mississippi Valley 

 and along the coast of the Mexican Gulf, it seems to be enzootic. 



Animals affected. — All of the domestic farm animals are, 

 more or less, susceptible to anthrax. The disease is transmissible, 

 also, to human beings, chiefly by inoculation, but may be con- 

 veyed by means of food or water, or through the inhalation of 

 dried spores, which afterwards develop into the rod-shaped or- 

 ganisms in the blood. 



Cause. — A microscopic rod-shaped organism or germ, the 

 Bacterium anthracis. The rod stage of the organism is found 

 in living blood, immediately after death, while the spore stage 

 occurs outside of the body. Some authorities claim that this 

 germ may, under certain conditions, lead a saprophytic existence, 

 that is, live upon decaying vegetable matter outside of the body. 

 The rod is more easily destroyed than is the spore. Where con- 

 ditions are favorable, such as the necessary amount of heat and 

 moisture, the spore may retain its vitality in surface soil, manure, 

 in infected feed-stuffs, blood, hides, hair and wool of anthrax 

 victims for long periods, and be capable of causing fresh out- 

 breaks. 



Modes of Transmission. 



(i) By the respiratory tract. — Dried spores may be in- 

 haled and reach the general circulation by way of the capillaries 

 of the lungs. Human beings following certain occupations, as 

 wool-sorting, mattress-making, etc., obtain infection in this way 

 more often than do the lower animals. 



*This lecture contributed by Dr. W. H. Dalrym'ple of Louisiana. 



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