MALLEIN. 249 



all cases there is first a lesion of the nasal mucous membrane 

 or of the skin surface, and that the lung is affected 

 secondarily. Babes, however, found that the disease could 

 be readily produced in susceptible animals by exposing 

 them to an atmosphere in which cultures of the bacillus had 

 been pulverised. He also found that inunction of the skin 

 with vaseline containing the bacilli might produce the disease, 

 the bacilli in this case entering along the hair follicles. 



Mallein and its Preparation. Mallein is obtained from cultures 

 of the glanders bacillus grown for a suitable length of time, and, like 

 tuberculin, is really a mixture comprising (i) substances in the bodies 

 of the bacilli and (2) their soluble products, not destroyed by heat, 

 along with substances derived from the medium of growth. It was 

 at first obtained from cultures on solid media by extracting with 

 glycerine or water, but is now usually prepared from cultures in 

 glycerine bouillon. Such a culture, after being allowed to grow for 

 three or four weeks, is sterilised by heat either in the autoclave at 1 15 

 C. or by steaming at 100 C. on successive days. It is then filtered 

 through a Chamberland filter. The filtrate constitutes fluid mallein. 

 Usually a little carbolic acid (.5 per cent) is added to prevent it from 

 decomposing. Of such mallein I c.c is usually the dose for a horse 

 (M'Fadyean). Foth has prepared a dry form of mallein by throwing 

 the filtrate of a broth culture, evaporated to one-tenth of its bulk, into 

 twenty-five or thirty times its volume of alcohol. A white precipitate 

 is formed, which is dried over calcium chloride and then under an air- 

 pump. A dose of this dry mallein is .05 to .07 gram. 



The use of Mallein as a means of Diagnosis. In using mallein for 

 the diagnosis of glanders, the temperature of the animal ought to be 

 observed for some hours beforehand, and, after subcutaneous injection 

 of a suitable dose, it is taken at suitable intervals, according to 

 M'Fadyean at the sixth, tenth, fourteenth, and eighteenth hours after- 

 wards, and on the next day. Here both the local reaction and the 

 temperature are of importance. In a glandered animal, at the site of 

 inoculation there is a somewhat painful local swelling which reaches a 

 diameter of five inches at least, the maximum size not being attained 

 until twenty-four hours afterwards. The temperature rises 1. 5 to 2 F. , 

 or more, the maximum generally occurring in eight to sixteen hours. 

 If the temperature never rises as much as i^, the reaction is considered 

 doubtful. In the negative reaction given by an animal free from 

 glanders, the temperature often rises i, the local swelling reaches the 

 diameter of three inches at most, and has much diminished at the 

 end of twenty-four hours. In the case of diy mallein, local reaction 

 is less marked. Veterinary authorities are practically unanimous as 

 to the great value of the mallein test as a means of diagnosis. 



