256 ACTINOMYCOSIS 
union stock yards, Chicago, show one case of actinomycosis in from 
1600 to 1700 cattle. The statistics from the abattoirs in Berlin show 
one case to 4150 cattle and one in 8000 pigs. These figures do not, 
however, indicate the extent of the disease among the farm animals, 
as they are collected from those animals presented for slaughter only. 
At the clinic of the New York State Veterinary College there are pre- 
sented for treatment a very few cases each year. In the Mississippi 
Valley and in the Southwest it seems to be more prevalent than it is 
east of the Alleghany Mountains. 
Fic. 53.. A ROSETTE OF THE RAY FUNGUS TOGETHER WITH DIFFERENT FORMS OF THE 
SINGLE CLUB ENDS. X 3500. (AFTER CROOKSHANK), 
Etiology. Actinomycosis is produced by a higher bacterium 
(Actinomyces bovis Harz, Streptothrix actinomyces Rossi Doria), com- 
monly known as the “ray fungus.” The disease is the result of its 
multiplying in the tissues and not from the elaboration of a toxin. 
Undoubtedly the lower bacteria often associated with it in suppurat- 
ing lesions are of some significance. Wright states that he believes 
they play an important part in the extension of the disease. The 
organisms appear as minute, yellowish granules in the lesions. 
When examined microscopically, these granules are found to be made 
