292 BACTERIOLOGY. 



White mice, common gray house-mice, rats, cattle, and 

 hogs are insusceptible. 



INOCULATION EXPERIMENTS. The most favorable 

 animal upon which to study the pathogenic properties 

 of this organism in the laboratory is the common field 

 mouse. When inoculated subcutaneously with a small 

 portion of a pure culture of the glanders bacillus death 

 ensues in about seventy-two hours. The most con- 

 spicuous tissue changes will be enlargement of the spleen, 

 which is at the same time almost constantly studded 

 with minute gray nodules, the typical glanders nodule. 

 They are rarely present in the lungs, but may frequently 

 be seen in the liver. From these nodules the glanders 

 bacillus may be obtained in pure culture. With the 

 exception of the characteristic nodule, the disease as 

 seen in this animal, presents none of the charcteristics 

 that it displays in the horse and ass. The clinical and 

 pathological manifestations resulting from inoculation of 

 guinea-pigs are much more characteristic. The animal 

 lives usually from six to eight weeks after inoculation, 

 and in this time becomes affected with a group of most 

 interesting and peculiar pathological processes. The 

 specific inflammatory condition of the mucous mem- 

 brane of the nostrils is almost always present. The 

 joints become swollen and infiltrated to such an extent 

 as often to interfere with the use of the legs. In male 

 animals the testicles become enormously distended with 

 pus, and on closer examination a true orchitis and 

 epididymitis is seen to be present. The internal organs, 

 particularly the lungs, kidneys, spleen, and liver, are 

 usually the seat of the nodular formations character- 

 istic of the disease. From all of these disease foci the 

 bacillus causing them can be isolated in pure culture. 



