132 MIOBOBES, FEEMBNTS, AND MOULDS. 



CHAPTER IV. 



MICROBES OF THE DISEASES OF OUR DOMESTIC ANIMALS. 



I. Anthrax, or Splenic Fever. 



The first of the virulent and contagious diseases in 

 which the presence of a microbe was positively 

 ascertained was anthrax, or splenic fever, which 

 attacks most of our horned animals, and especially 

 cattle and sheep. 



As early as 1850, Davaine had observed the 

 presence of minute rods in the blood of animals which 

 died of splenic fever ; but it was only in 1863, after 

 Pasteur's first researches into the part played by 

 microbes in fermentations, that Davaine suspected 

 these rods of being the actual cause of the disease. 

 He inoculated healthy animals with the tainted blood, 

 and thus ascertained that even a very minute dose 

 would produce a fatal attack of the disease, and the 

 rods, to which he gave the name of Bacteridia, could 

 always be discovered in enormous numbers in the 

 blood. 



