820 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



of local lymph glands, and constitutional disturbances soon follow the 

 local symptoms. Human glanders is to be always regarded as very 

 serious with a probability of fatal termination. Ulcers may develop 

 in the nose or mouth with more or less discharge. Pustules appear 

 involving the skin, and abscesses involve deeper structures in various 

 portions of the body. 



The distribution of Bact. mallei in the animal body is shown by the 

 most common appearance of its disease in the skin, subcutaneous 

 tissue, mucous membranes, lymphatic system, lungs, liver, spleen and 

 kidneys. 



The etiological factor is a small bacillus with rounded ends known 

 as Bact. mallei, discovered by Loeffler and Schiitz and several others 

 in 1882, and well demonstrated to be the specific cause of glanders. 



Entrance is usually effected by way of a mucous membrane, fre- 

 quently the intestinal, sometimes by inoculation. The period of 

 incubation seems variable and uncertain under natural infection, but 

 in artificial inoculation with virulent cultures, is very brief. 



Bact. mallei produces toxins in artificial media and also in body 

 tissues; the well-known preparation called mallein may be considered 

 in. this class awaiting more definite knowledge. This substance 

 produces a distinct reaction by inoculation into glandered animals, 

 but is practically non-toxic for healthy equines. So far as known 

 Bact. mallei attacks the animal tissues as do many other microorganisms, 

 the harm resulting chiefly from bacterial toxins which give the local 

 tissue reactions leading to the lesions characteristic of glanders. 



In its action on tissues Bact. mallei resembles Bact. tuberculosis; 

 but shows a more rapid development of lesions and more active in- 

 flammation. 



Lesions are of two types a well-defined nodule followed by ulcera- 

 tion and areas of diffuse infiltration. 



The nodule as it appears in glanders consists largely of lymphoid 

 cells and connective tissue, the latter increasing as the case becomes 

 chronic. Nodules die at the center, suppurate, and discharge. This 

 occurs especially in the external form of glanders, which affects more 

 commonly the legs and head. Occasionally defined enlargements 

 appear in the involved lung areas. Pulmonary lymph glands are 

 frequently enlarged, and hardened. The superficial skin lesions are 

 in the form of nodules previously mentioned, which usually suppurate 



