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. 



