LECTURE XXXIII 

 ANTHRAX ' 



One of the oldest diseases known to medical science and one 

 which is almost world wide is anthrax. It afifects a wide range 

 of subjects and is usually fatal. 



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

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

 very fatal to human beings, chiefly by inoculation, but it may 

 be taken by means of food or water, or by the inhalation of 

 dried spores. 



Cause. — Anthrax is caused by a microscopic rod-shaped or- 

 ganism 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. •«««^^— — — •« 

 The rod is more easily destroyed than fig. 56.— b a c t e r i u m 

 is the spore. The spore may retain its (Bacillus)^Anthracis. 



vitality in surface soil, manure, in- The specific 'cause of an- 

 fected foodstuffs, blood, hides, hair and thrax. 

 w'ool of anthrax victims for long pe- 

 riods, and be capable of causing fresh outbreaks. A contamin- 

 ated pasture for example remains infectious for years. 

 • The period of incubation is probably short. In experimental 

 animals it varies from one to five days. 



No true toxin has been demonstrated for this virus; but B. 

 anthracis may be present in the blood in such numbers as to 

 block the capillaries. It also produces an enzyme which digests 

 blood serum and destroys the red corpuscles. 



Modes of infection.— (1) Dried spores may be inhaled and so 

 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 originally by Dr. W. H. Dalrymple, of Louisiana, 

 and later revised by the author. 



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