346 VETERINARY BACTERIOLOGY 



clubs, frequently occur. The organism is non-motile, and does not 

 produce spores or capsules. It stains readily with the common 

 anilin dyes, but is gram-negative. 



The peculiarities of staining, the possession of easily stained 

 granules, or of a vacuolate protoplasm, have caused some authors 

 to group this germ with the diphtheria bacillus, but these ap- 

 pearances are even more characteristic of certain of the Actino- 

 myces, particularly those isolated from soil. 



Isolation and Culture. Bacillus necrophorus is most easily 

 isolated in pure culture by inoculating infected tissue into rabbits 



Fig. 144. Bacillus necrophorus (Mohler, Bureau of Animal Industry, Circular 



No. 160). 



or white mice. The pure culture may then be secured from the 

 infected organs. The cultural characters are all modified by the 

 fact that the organism is a strict anaerobe. 



Colonies may develop upon the surface of agar plates if the 

 oxygen is removed by the alkaline pyrogallate method, but not, 

 according to Mohler and Morse, in an atmosphere of hydrogen 

 or in a vacuum. They appear in forty-eight hours as minute, 

 dirty white, round, opaque colonies, with gas-bubbles developing 

 below the surface. In seventy-two hours the colony appears 

 wooly, and the central portion, upon microscopic examination, is 

 shown to be a felted mass of threads with a border of long, wavy 



