CHAPTEE XX. 



ANTHRAX BACILLUS. 



Occurrence and Pathogenesis. Anthrax, splenic fever, malignant 

 pustule, carbuncle, woolsorter's disease, Milzbrand (German), char- 

 bon (French), is a disease of man and the lower animals which has 

 apparently been known to mankind for thousands of years. It is 

 probably the affection referred to in the Bible (Exodus, ix, 3-9), and 

 it is mentioned by several of the classic Greek writers, including 

 Homer. Its names are derived from the most obvious anatomic 

 lesions, enlargement, softening, and congestion of the spleen (splenic 

 fever, Milzbrand), and the widespread occurrence of acute passive 

 congestion and acute hemorrhagic infiltration of the subcutaneous, 

 subserous, and submucous tissues, which generally give to them a very 

 dark brown or dark purple or sometimes an almost black color. The 

 term anthrax is derived from the Greek word for coal, which is also 

 the meaning of the French charbon. The designation woolsorter's 

 disease is derived from the fact that the handlers of hides from cows 

 or wool from sheep dead from anthrax often contracted the disease, 

 which in this case usually assumes the local character of a malignant 

 pustule or carbuncle or an inhalation pulmonary affection. The disease 

 is caused by a pathogenic microorganism known as the anthrax 

 bacillus. It is most common among cattle and sheep, but also occurs 

 in man, horses, hogs, goats, deer, hares, buffaloes, dogs, cats, and very 

 rarely among chickens, ducks, and geese. An anthrax epidemic among 

 the wild animals of the zoological garden of Copenhagen has been 

 described by Jensen, and a laboratory epidemic among guinea-pigs 

 that contracted the disease from anthrax-infected peat has also been 

 reported. The susceptible laboratory animals used in experimental 

 work are mice, guinea-pigs, and rabbits. Gray rats are very slightly 

 susceptible, white rats more so. Anthrax is prevalent particularly 

 among cattle and sheep practically throughout the entire world. It 

 has been found in Europe, Asia, Africa, Australia, and North and 

 South America, but it is by no means equally distributed in all places, 

 being much more prevalent in moist, marshy lowlands or prairies 

 than in dry, rocky soil. It is endemic in favorable localities, where it 

 finds its numerous victims year after year; it also occurs in sporadic 

 outbreaks. 



Pathologic Lesions. The anatomical changes of anthrax are quite 

 characteristic. The blood, on account of a lack of oxygenation due 

 to toxic influences, becomes very dark and does not promptly and 

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