48 BACILLUS MALLEI (GLANDERS) 



not stain very readily, owing, it would seem, to the 

 protective slimy envelope which gives to the growth 

 the gelatinous character which has been mentioned. 

 Susceptible animals — e.g., guinea-pigs — succumb to 

 subcutaneous and intra-peritoneal inoculations ; the 

 internal organs are studded with the characteristic 

 lesions. In the male guinea-pig the testicles are 

 peculiarly liable to suffer after intra-peritoneal in- 

 jection, a severe epididymitis and orchitis being set 

 up. This reaction in the animal is very useful in 

 the diagnosis of glanders in man. A section of 

 testicle from such an infected animal is represented 

 in Fig. 42. The lesion figured is a very early one, 

 and the alterations in the tissue correspondingly 

 slight, but a group of bacilli is seen. The organisms 

 are often met with in the cells. 



A substance, "mallein," corresponding both in 

 origin and in specific action to tuberculin, has been 

 obtained. 



It is doubtful whether susceptible animals have 

 been successfully immunised. 



