212 TEXT-BOOK OF BACTERIOLOGY. 



susceptible by diminishing- the alkalescence of its body; Emmerich, 

 Pawlowsky, Bouchard, and Freudenreich repressed a commencing* 

 anthrax infection and cured it by introducing- other micro-organ- 

 isms, such as the erysipelas coccus, the Micrococcus prodigiosus, 

 and the Bacillus pyocyaneus facts which, as we have seen, confirm 

 us in the belief that the effects are produced chiefly by the excre- 

 tions of the bacteria. 



By microscopic examination, by cultivation outside the animal 

 body, and by successful transmission from artificial cultures, we 

 know that the anthrax bacillus is the sole cause of anthrax disease. 

 How are the peculiar phenomena of the disease to be explained as 

 resulting from the properties and habits of the bacillus ? 



It was stated that splenic fever is one of the most wide- spread 

 of all infections. In fact, there is scarcely any country where it is not 

 known, while some are particularly subject to it. In France and 

 Germany, Hungary and Russia, India and Persia it spreads its 

 ravages every year among the most valuable cattle, and the num- 

 ber of its victims amounts to thousands; in Siberia it is such a terri- 

 ble scourge that it has been taken for an evil peculiar to that 

 country and called the Siberian pest. Only England and North 

 America are comparatively free from it, and it only occurs there in 

 isolated cases. 



There are generally certain smaller districts notorious for its 

 prevalence ; such in Germany are the Upper Bavarian Alps, and in 

 France, Auvergne, where it is said to have existed thousands of 

 years, and whence, according to Pliny, it had spread, 800 years before 

 his own time, into Italy. 



It is at its maximum in the hot summer months from June to 

 September; the coming of winter almost always causes a temporary 

 cessation of it. The special influence of dry or damp or otherwise 

 exceptional weather has not been actually observed. 



Taken as a whole, the explanation of these facts is not difficult. 

 We are aware that the bacillus is capable of living saprophytically 

 and of finding suitable conditions of existence outside the bodies of 

 animals. Where it finds these conditions in the greatest perfec- 

 tion, the disease will naturally break out most frequently and be 

 most destructive. That this should generally occur in summer is 

 also natural, since at that season the surface of the soil is, for a 

 longer or shorter time, at about the temperature best suited for 

 the development of the bacteria. 



Yet with all this the chief question remains unanswered: How 

 does the bacillus find its way into the body, how does the animal 

 become infected, and how does this plague spread among cattle ? 



