BACILLUS MALLEI 371 



localization of the bacilli in the testes, which become inflamed and 

 swollen the Straus reaction. The animal usually dies within a 

 week. Potato cultures and microscopical examination of the purulent 

 material in the testes usually suffices to establish the diagnosis. In 

 case the material for examination is contaminated with other bacteria, 

 it is advisable to inoculate it into the subcutaneous tissues of one 

 guinea-pig, and to inoculate a second male pig with material from 

 an enlarged lymph gland of the first pig. A negative examination 

 is inconclusive. 



Serological Diagnosis. (a) Mallein. Discussed above. 



(6) Ophthalmo Reaction. The instillation of a few drops of mallein 

 into the conjunctival sac of a glanderous horse leads to a reaction 

 very similar to the ophthalmo-tuberculin reaction in man, except 

 that in positive cases a purulent discharge as well as a red inflamed 

 conjunctiva results. 



(c) Agglutination Test. Specific agglutinins for Bacillus mallei 

 appear in the blood of infected animals usually within four to seven 

 days in acute glanders, and there is a rough parallelism between the 

 severity of the disease and the development of the immune bodies. 

 The agglutinins as a rule diminish considerably if the disease becomes 

 chronic, and may become reduced to such a degree that the reaction 

 becomes unreliable. The sera of normal horses frequently contain 

 non-specific agglutinins which may clump glanders bacilli in dilutions 

 of 1 to 100 to 1 to 300. Injections of mallein appear to influence 

 antibodies specific for the glanders bacillus adversely, consequently 

 serological examinations should be made before mallein is injected. 



Serum for agglutination tests should be withdrawn in a sterile syringe 

 from the jugular vein in the horse, and from the median basilic vein 

 in man. The serum, separated from the clot, is diluted with a suspen- 

 sion of glanders bacilli to the following degrees: 1 to 500, 1 to 1000, 

 1 to 2500, 1 to 5000, 1 to 7500. Glanders bacilli, virulent for guinea- 

 pigs (obtained by passing glanders bacilli through a series of animals 

 until the organism kills the animal within five days intraperitoneal 

 injection), from glycerin agar slants are emulsified in physiological 

 salt solution containing 0.5 per cent, carbolic acid, thoroughly shaken 

 and filtered through a thin layer of absorbent cotton to remove clumps. 

 Salt-phenol solution is added to the suspension until a moderately 

 turbid suspension is obtained. Decreasing amounts of serum from 

 the suspected animal are added to obtain the dilutions mentioned 

 above. A normal serum and a known positive serum are diluted in 



