MALLEI N. 



625 



The method by which the mallein of Koux and 

 Nocard is prepared is identical with that used in 

 the preparation of the old tuberculin. A virulent 

 strain of the glanders bacillus is allowed to grow 

 for some time (from two weeks to two or three 

 months) in bouillon which contains from 4 to 5 

 per cent, of glycerin, the culture is then sterilized 

 by heat and the bacteria removed by filtration. 

 The toxin is not destroyed by high temperature. 

 Other preparations, also called mallein, are made 

 by extracting ground-up bacilli with a solution of 

 glycerin and water (Helman, Kalning), or with 

 water alone (Kalning and others) ; by killing a 

 liquid culture of the bacillus (Bromberg) ; or by 

 precipitating bouillon filtrates with absolute alco- 

 hol (de Schweinitz and Kilbourne), or with am- 

 monium sulphate or magnesium sulphate. The 

 dry powders "morvin" and "dried mallein" are 

 prepared by one or another of these precipitation 

 methods. 



Glanders bacilli are found only in the tissues Distribution 

 and secretions of diseased animals, and the nasal infection 

 discharges of the latter are the chief means of con- 

 taminating feed, water and stables through which 

 the disease usually is carried to other animals. 

 The glanders bacillus does not readily penetrate 

 the intact skin and mucous membranes, although 

 occasionally it may gain entrance through the hair 

 follicles or sweat ducts. In the presence of even 

 slight defects in these surfaces, as those caused in 

 the mouth or nostrils of horses by hay or other 

 food, infection readily occurs. According to No- 

 card, invasion takes place commonly through the 

 gastrointestinal tract following the ingestion of in- 

 fected feed or water. Although involvement of the 



