488 MICROBIOLOGY OF SPECIAL INDUSTRIES. 



MALLEIN. 



Mallein is prepared from cultures of Bact. mallei by practically the 

 same methods as those employed in manufacturing tuberculin from 

 Bact. tuberculosis. The product is used for the diagnosis of glanders. 

 A few hours after mallein is injected into glandered horses a severe local 

 reaction and a rise of temperature usually follow. The thermal reaction 

 is very similar to that produced in tuberculous animals by the injection 

 of tuberculin. The local swelling caused by mallein treatment is con- 

 sidered by some to be quite as diagnostic as the temperature reaction. 



The stock culture of the glanders organism used in the preparation 

 of mallein should be one which possesses known virulent properties. 

 It is grown at a temperature of 37 for several weeks in flasks of glycerin 

 bouillon having a chemical reaction of about three degrees acid to phenol- 

 phthalein. When the cultures are removed from the incubator they are 

 heated in streaming steam, passed through a Berkefeld filter and the 

 filtrate is concentrated, preserved and distributed in labeled vials as in 

 the preparation of tuberculin. 



SUSPENSIONS FOR THE AGGLUTINATION TESTS. 



Agglutinins are hypothetical bodies existing in the blood and possibly 

 other body tissues, of an individual affected with, or convalescent from, a 

 specific infectious disease. The bodies possess the power of " clumping" 

 and precipitating the specific bacteria which are the cause of the disease 

 in question. Thus, if a dilution of blood serum from a typhoid fever 

 patient is mixed with living typhoid organisms, the specific agglutinins 

 present in the serum will cause the organisms to cease their motion and 

 agglutinate or clump together in irregular masses. Normal human 

 blood serum placed under the same conditions will fail to cause the 

 agglutination of the organisms. The agglutination reaction may therefore 

 be used in the diagnosis of certain specific infectious diseases. The serum 

 must be diluted to a certain degree in order that the reaction may be of 

 diagnostic value, because undiluted, normal serum will cause a positive 

 agglutination reaction in most cases. 



The agglutination test is used as a practical aid chiefly in typhoid 

 fever in man and glanders in horses. The test may be conducted either 

 microscopically or macroscopically. In the microscopic method, the 



