PATHOGENIC BACTERIA. 297 



Bacillus mallei (of glanders). A slim bacillus with 

 round or pointed ends, which often shows alternate light 

 and dark spots in stained preparations. Branching forms 

 have been described. It is not motile. It probably does 

 not form spores. It is decolorized by Gram's method. 

 After staining with the ordinary aniline dyes it is easily de- 

 colorized, and on that account it is difficult to demonstrate 

 in sections of tissues. It is facultative anaerobic. It grows 

 at the room temperature, but better in the incubator. It 

 grows slowly on gelatin, and does not liquefy it, or only 

 after a long time. On agar it produces a moist, white 

 growth, on blood-serum a yellowish or brownish growth; 

 blood-serum is not liquefied. Milk is coagulated slowly, 

 and the reaction becomes acid. On potato the growth is 

 characteristic in one or two days in the incubator, becom- 

 ing translucent amber-yellow, later a reddish-brown, while 

 the surface of the potato becomes discolored. 



It is killed in five minutes by a 5 per cent, solution of 

 carbolic acid, in two minutes by 1-5000 bichloride of mer- 

 cury. It may survive drying for a number of weeks. 



In the horse and ass it produces the disease known as 

 glanders, which affects the mucous membrane of the nasal 

 cavity. When the skin is involved the disease goes by the 

 name of farcy. In the nose, nodules appear in the mucous 

 membrane which become necrotic, forming ulcers. They 

 may become confluent, and may extend along the adjacent 

 surfaces as far as the lungs. There is a profuse discharge 

 from the nose. The neighboring lymph-nodes become in- 

 volved and are swollen, and nodules may be present in the 

 internal viscera. In the skin the nodes lying underneath 

 the skin are called farcy-buds. Histologically the nodules 

 consist of a granulation tissue, but they tend to break down 

 rapidly, and the process in some respects is very like ordi- 

 nary suppuration. 



