34 Veterinary Medicine. 



torn or seacoast, yet its greatest prevalence is unmistakably in 

 connection with low, damp, rich bottom land. In Great Britain 

 we find it very common in the fens of I<incoln and Norfolk 

 (Crookshank) and in river bottoms ; in Holland it is a disease of 

 the polders (Jensen); in Germany it is frequent on the low, damp 

 lands of Marienburg and Ebling (Preusse), and in Russia on the 

 rich Steppes stretching along the Volga (Mari) and Dnieper 

 (Korsak). At some points in the Mississippi Valley it is very 

 common and encreasingly so as the general use of barbed wire 

 furnished more numerous infection atria. Immenger has found 

 it very prevalent in the Bavarian Palatinate and in Franconia. 

 The abattoir statistics show for Berlin, in cattle, i :50oo, and in 

 swine, 1:150000 ; for Augsburg, in cattle, 1:3000; for Bremen, 

 in catlle, 1:4250, and in swine, 1:8000; for Stuttgart, in cattle, 

 1:1000; for Hanover, in cattle, 1:10000; for Moscow, in cattle, 

 1:3000, and for Warsaw, in cattle, 1:5000. In Moscow, Oskol- 

 kow estimates the ratio at 2.5 to 5.5 per cent. In Chicago, Sal- 

 mon gives the ratio as 0.2 per cent. In La Villette, France, 

 Nocard gives 0.7 per cent. 



Etiology. The cause of actinomycosis is the propagation in 

 the tissues of the .actinomyces. A variety of conditions may, 

 however, contribute to this. As already stated it seems to be 

 most prevalent on low, damp, rich soils where the pathogenic or- 

 ganism may find a favorable field for saprophytic growth. It has 

 been supposed to grow especially on cereals and particularly bar- 

 ley, the beards of which favor its entrance into wounds of the 

 skin and mucosae. But the disease is found on western ranges 

 where the cereals are never seen and must be traced to other 

 forms of the gramineae or to diverse vegetation and soil. 



Whatever furnishes a favorable infection atrium contributes to 

 its prevalence. In swine the follicles of the tonsils have been 

 found to enclose the parasite (Johne, Plana). The period of 

 teething and the attendant laceration of the gums afford opportu- 

 nity for colonizing, hence youth is a strongly predisposing condi- 

 tion. The relatively large size of the tonsils in early life, the 

 softness and yielding character of the buccal mucosa, the conges- 

 tion of the latter in connection with sucking, and the tendency to 

 aphthous stomatitis, all contribute to an invasion. In older ani- 

 mals the winter season is the main period of invasion, the dry. 



