492 



PRINCIPLES OF VETERINARY SURGERY 



These investigations were i^apidly followed by many oth- 

 ers. In the course of a few years the parasite was discov- 

 ered, studied, and described in nearly every country of Eu- 

 rope. Johne tried to cultivate it in 1885, as did other nu- 

 merous experimentalists. 



In France, the disease was recognized by Nocard in 1885. 

 The following year Professor Thomassen reported the suc- 

 cessful results of treatment with iodine. Since that time 

 publications on the subject have been very numerous, and 

 they have dealt with every point. It may be safely said that 



Fig. 51. 



Actinomyces from Tumor of the Inferior Maxillary of an Ox. 1. One Granu- 

 lation Entire. 2, 3, 4, 5, 6, 7, Diflferent Club-Shaped Forms ; 8, 9, 

 10, Rounded Elements. 



actinomycosis has been more closely studied than most any 

 other disease. 



Character of the Parasite in the Tissues. — When a sec- 

 tion is made through an actinomycostic lesion, or when the 

 pus discharging from the fistulae of the tumors is examined, 

 "yellow grains" are seen at the surface of the section or in- 

 corporated with the pus. These grains, when calcified, feel 

 like fine sand, and the proof of their presence reveals the 

 exact nature of the morbid process. They vary in size ; 

 some are microscopic, while others, on the contrary, are the 

 size of a pin-head. They are coated with gelatinous sub- 

 stance that is difficult to remove completely. 



