308 GLANDERS BACILLUS 



lar, cutaneous eruption before death occurs. In man the various types 

 usually take an acute rapid course. The chronic type of cutaneous 

 glanders with the formation of abscesses, ulcers, and lymphatic 

 swelling and involvement has also been observed in man. Cases of 

 this kind have formerly been mistaken for tertiary syphilitic lesions. 

 More acute cases resembling smallpox in man have been reported by 

 Wherry, Zeit, Bevan and Hamburger, and others. 



Morphology. The Bacillus mallei varies considerably in size and 

 shape according to the culture medium on which it has been grown. 

 It is, as a rule, rather slender; occasionally, however, it is short and 

 plump. It is from 2 to 5 micra long and from 0.5 to 1 micron in 

 diameter. On old potato cultures the bacillus sometimes appears 

 in long filaments forming intertwined, irregular masses. Bacilli of 

 the ordinary, most common type are generally not perfectly straight, 

 but slightly curved. They do not stain uniformly, but somewhat in 

 the manner of the diphtheria bacillus. The Bacillus mallei is not 

 actively motile, but shows a very lively molecular movement; it does 

 not form spores nor does it stain well with the ordinary watery anil in 

 stains, but takes better the stronger stains such as Loeffler's alkaline 

 methylene blue, Kuehne's carbolmethylene blue or carbol-thionin. 

 Loeffler has recommended the following method for staining for 

 glanders bacilli in smears from suspected pus or necrotic material: 



1. Prepare the cover-glass smear in the usual manner, air dry, 

 fix and float the cover-glass for five minutes on Loeffler 's alkaline 

 methylene blue. 



2. Dip for one second into a 1 per cent, watery solution of acetic 

 acid to which enough of a watery solution of tropeolin 00 has been 

 added to give it a Rhine-wine yellow color. 



This last step decolorizes the cell protoplasm entirely and the 

 nuclei partially, so that the deep blue stained bacilli can be more 

 readily found. 



Cultural and Biologic Properties. The Bacillus mallei can be 

 obtained in pure culture without great difficulty. It is generally 

 impossible to obtain it directly from the discharges from glanderous 

 lesions in the horse. As a rule, it is necessary first to inoculate a guinea- 

 pig in the manner described below. The bacillus grows best between 

 30 to 40 C.; growth ceases at and below 20 C. and above 43 C. 

 It is a strict parasite which has never been found under natural con- 

 ditions except in connection with cases of glanders. If cultures have 

 been raised for many generations on artificial media the bacillus 

 may also grow at temperatures lower than 20 C. The organism grows 

 much better in artificial cultures in the presence of oxygen; in its 

 absence there is only a very poor development. The culture media 

 may be faintly alkaline, neutral or faintly acid; the latter reaction is 

 most favorable. The addition of glycerin, 4 or 5 per cent, to the 

 agar or bouillon, is advantageous to the development of the Bacillus 

 mallei. In ordinary bouillon or glycerin bouillon the Bacillus mallei 



