INFECTION. 107 



A Russian commission, appointed to look into the causes of anthrax, 

 reported the chief cause of the epizootic outbreaks of the disease to 

 he the inco?npIet'.' burial and removal of the cadavers of horses 

 which had perished from it. 



Every animal diseased witli anthrax, or its cadaver, or any por- 

 tion of the same, must be looked upon as a dangerous center from 

 which infection may proceed. 



The physical conditions of the earth, viz., its amount of water, 

 chemical constituents, and temperature, must always be looked upon 

 in considering the generation of anthrax. 



Practical experience goes to prove that extreme drying out or 

 draining of a suspected or known district is unfavorable to the de- 

 velopment of its infectious elements.' In such cases, rains following 

 great heat and drought are generally characterized either by the re- 

 appearance of the disease or its greater prevalence. On the con- 

 trary, drought and heat favor its appearance in very moist districts. 

 The disease is generally most prevalent in such districts when the 

 temperature of the earth has reached its highest maximum. This 

 is generally in our latitude in the months of August and September. 



A question of importance in the generation of this disease is, Is 

 an impregnation of the earth with the infectious elements necessary 

 to the development of the disease, or are they capable of independ- 

 ent development in such earth by the metamorphosis from some 

 other kind of fungi already present ? 



The previously mentioned practical observations of the careful 

 removal of cadavers, instead of burial, would seem to favor the 

 first of these views. 



The chief, if not the only, cause of anthrax must be sought in 

 infection, in general, not direct, but by means of some vehicle, the 

 infectious elements being extremely tenacious of life and easily 

 transported, as has been painfully illustrated by cases in man due to 

 dried hides brought from a distance, curled hair, or other animal 

 derivatives. 



The most frequent carriers of infection are cither diseased ani- 

 mals, their excretions, or their products — hides, horns, hoofs, etc. 

 Again, healthy animals, or even men, flies, gnats, etc., may serve as 

 vehicles to infection. Gerlach reports numerous cases among shec]) 

 due to the bite of the dogs used to tend them, where the latter have 

 been fed or have fed themselves upon the cadavers of sheep that 

 had perished from the disease. 



Davaine frequently produced the disease by inoculations with 

 the probosces or feet of flies which had first been permitted to pol- 



