72 STUDY AND IDENTIFICATION OF BACTERIA. 



leprosy bacillus by Gram's method, it as well as the tubercle bacillus 

 being Gram positive. 



NONACID-FAST BRANCHING BACILLI. 



Bacillus Mallei (Lofifler and Shutz, 1882). This is the cause of a 

 rather common disease of horses. When affecting the superficial 

 lymphatic glands, it is termed "farcy;" when producing ulceration 

 of nasal mucous membrane, the term "glanders" is used. 



In man there are two types of glanders chronic and acute. In the 

 chronic form an abrasion becomes infected from contact with glanders 

 material and an intractable foul discharging ulceration results. This 

 may persist for months with lymphatic involvement or may become 

 acute. The acute form may also develop from the start and the cases 

 are usually diagnosed as pyaemia. Death invariably results in acute 

 glanders. The bacillus is a narrow, slightly curved rod, about 3 x .^IJL. 

 It is nonmotile and Gram negative. It at times presents a beaded 

 appearance. In subculture on agar or blood-serum the growth is 

 somewhat like typhoid, but more translucent. In original cultures 

 from pus or tissues the colonies may not show themselves for 48 hours. 

 The characteristic culture is that on potato. Grown at 37 C., we have 

 a light brown mucilaginous growth, which by the end of a week spreads 

 out and takes a cafe au lait color. The potato assumes a dirty-brown 

 color. This and the inoculation of a guinea-pig are the chief diag- 

 nostic measures. If the material is injected intraperitoneally into a 

 male guinea-pig, marked swelling of the testicles is noted within 48 

 hours. 



The best stains are carbol thionin and formol fuchsin. In sections 

 stained with carbol thionin the bacilli are apt to be decolorized by the 

 subsequent passage of the section through alcohol and xylol. This 

 may be avoided by blotting carefully after the thionin, then clearing 

 with xylol or some oil, and mounting. Nicolle's tannin method is a 

 good one. 



Mallein is prepared by sterilizing cultures that have grown in 

 glycerin bouillon for about a month by means of heat (100 C.). 

 The dead culture is then filtered through a Berkefeld filter and the 

 filtrate constitutes mallein. It is chiefly used as a means of diagnosing 



