278 GLANDERS. 



Agglutination of Glanders Bacilli. Shortly after the discovery of 

 agglutination in typhoid fever, M'Fadyean showed that the serum of 

 glandered horses possessed the power of agglutinating glanders bacilli. 

 His later observations show that in the great majority of cases of 

 glanders a I in 50 dilution of the serum produces marked agglutina- 

 tion in a few minutes, whilst in the great majority of non-glandered 

 animals no effect is produced under these conditions. The test 

 performed in the ordinary way is, however, not absolutely reliable, 

 as exceptions occasionally occur in both directions, i.e., negative 

 results by glandered animals and positive results by non-glandered 

 animals. He finds that a more delicate and reliable method is to 

 grow the bacillus in bouillon containing a small proportion of the 

 serum to be tested. In this way he has obtained a distinct sedi- 

 menting reaction with a serum which did not agglutinate at all 

 distinctly in the ordinary method. Further observations are still 

 required to determine the precise value of the test. 



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 115 

 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 grm. 



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 definite 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 C., 

 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 



