CHAPTER XXIX. 



THE ANTHRAX BACILLUS AND THE BACILLUS OF SYMPTOMATIC 



ANTHRAX. 



Bacillus Anthracis. 



ANTHRAX is an acute infectious disease which is very prevalent 

 among animals, particularly sheep and cattle. Geographically and 

 zoologically it is the most widespread of all infectious disorders. It 

 is much more common in Europe and in Asia than in America. The 

 ravages among herds of cattle in Russia and Siberia, and among sheep 

 in certain parts of France, Hungary, Germany, Persia, and India 

 are not equalled by any other animal plague. Local epidemics have 

 occasionally occurred in England, where it is known as splenic fever. 

 In this country the disease is rare. In infected districts the greatest 

 losses are incurred during the hot months of summer. 



The disease also occurs in man as the result of infection, either 

 through the skin, the intestines, or in rare instances through the lungs. 

 It is found in persons whose occupations bring them into contact with 

 animals or animal products, as stablemen, shepherds, tanners, butchers, 

 and those who work in wool and hair. Two forms of the disease have 

 been described the external anthrax, or malignant pustules, and the 

 internal anthrax, of which there are intestinal and pulmonary forms, 

 the latter being known as "wool-sorters' disease." 



Owing to the fact that anthrax was the first infectious disease which 

 was shown to be caused by a specific micro-organism, and to the close 

 study which it received in consequence, this disease has probably con- 

 tributed more to our general knowledge of bacteriology than any other 

 infectious malady. 



Pollender in 1849 observed that the blood of animals suffering from 

 splenic fever always contained minute rod-shaped bacteria. Davaine 

 in 1863 announced to the French Academy of Sciences the results of 

 his inoculation experiments, and asserted the etiological relations of 

 the micro-organism to the disease, \vith which his investigation showed 

 it to be constantly associated. For a long time this conclusion was 

 energetically opposed until, in 1879, Pasteur, Koch, and others estab- 

 lished its truth by obtaining the bacillus in pure cultures, and showing 

 that the inoculation of these cultures produced anthrax in susceptible 

 animals as certainly as did the blood of an animal recently dead from 

 the disease. 



Morphology. Slender, cylindrical, non-motile rods, having a breadth of 

 I/* to 1.25/>, and ranging from 2// or 3/J. to 20// or 25/> in length. Some : 



