218 GLANDERS AND ACTINOMYCOSIS. 



stained specimen appears to be fragmented, and this has given 

 rise to the belief that it produces spores. Bacillus mallei is a 

 facultative anaerobe. It grows readily on all culture-media 

 at a temperature anywhere between 25 and 40 C., the 

 optimum being 37 C. 



Vitality: The bacillus is killed in ten minutes by exposure 

 to a temperature of 55 C. ; in five minutes by a 5 per cent, car- 

 bolic acid solution ; in two minutes by a 1 : 5000 solution of 

 mercuric chloride. It will resist drying for months. The 

 organism does not thrive as a saprophyte, and must be classed 

 as an obligative parasite. 



Pure cultures are made from the nasal mucus or the tissues 

 of animals suffering from glanders. A very rapid method is 

 to inject the suspected material into the peritoneal cavity of 

 a male guinea-pig. If the glanders bacillus is present, the 

 testicles will be involved early. They break down and fre- 

 quently discharge through the skin. The animal. is killed, 

 and on removing the testicles the tunica vaginalis is found 

 full of fluid pus, from which the germ is obtained in pure 

 culture. It will grow on any media, but best on glycerin- 

 agar, blood-serum, and potato. 



On glycerin-agar plates it forms small, glistening, finely 

 granular, yellowish colonies within forty-eight hours. In 

 stroke cultures on glycerin agar and blood-serum the growth 

 develops along the entire needle-track as a very thick moist 

 white membrane. Gelatin is slightly liquefied. Bouillon is 

 clouded. 



On potato the growth is quite characteristic. It first forms 

 a luxuriant moist yellow coating, which gradually turns to a 

 deep reddish-brown. The potato around the culture takes on 

 a greenish-yellow tinge. Milk is coagulated with the pro- 

 duction of acid. The glanders bacillus loses its virulence in 

 culture, but regains it when it is passed through animals. 



Pathogenesis : Glanders is primarily only a disease of ani- 

 mals, especially the horse ; but man is extremely liable to con- 

 tract the disease from~infected animals. Cases of glanders 

 have also been reported frequently in the persons of laboratory 

 assistants. The greatest care should be taken in the handling 

 of this or any other pathogenic organism. The glanders 



