150 THE MORE CHRONIC INFECTIOUS DISEASES 



BACTERIUM MALLEI. 



Glanders is chiefly a disease of horses, characterized by 

 nodular growths and ulcers in the upper air passages or diffuse 

 swellings under the skin. In the latter form it is called farcy. 

 The causative organism is the Bacterium mallei or glanders 

 bacillus. Human beings, who are associated with horses or 

 who work in the laboratory with cultures, may contract the 

 disease, usually, however, in the acute form, whereas the 

 lower animals commonly have a protracted attack. The 

 bacteria enter by small cracks or wounds in the mucous 

 membrane of the mouth or nose, and are carried by the lymph 

 or blood to subcutaneous tissues. Whether they produce 

 glanders proper or farcy, they stimulate the tissues to pro- 

 duce nodules not unlike the tubercle, but of more rapid 

 progression. Quite early they break down into abscesses or 

 through the skin as large sloughing ulcers. The poisons are 

 almost entirely endotoxins, and may be extracted from cul- 

 tures. A slight amount of resistance is -gained by passing 

 through an attack. 



Diagnosis. Agglutinins are found in the blood and the 

 clumping test is a valuable means of diagnosis. The bacteria 

 may also be found by making smears and cultures from open 

 ulcers or by withdrawing some of the pus from an abscess. 

 This pus may be injected into the peritoneal cavity of a 

 guinea-pig, obtaining as evidence of the presence of the 

 Bacterium mallei an inflammation of the testis. The most 

 practical method of diagnosticating glanders is by the use of 

 the mallein test. Mallein is the poison elaborated by the 

 Bacterium mallei in laboratory cultures. It is comparable 

 to tuberculin, and may be used like it, by injecting it under 

 or by rubbing it upon the skin. Reactions of temperature 

 and reddening of the skin indicate the presence of glanders. 

 The bacilli may be found also in stained smears of the pus 

 lying in pairs on end within the large so-called epithelioid 

 cells. Blood cultures sometimes give a growth. The disin- 



