DIAGNOSTIC INOCULATION. 239 



with the aid of the glanders antibodies, have the power to fix 

 the antigen. This fixing power is increased by heating the 

 mixture at 37°C. in a thermostat. The diagnosis of glanders 

 by this method consists in the determination of the amount of 

 antibodies of glanders bacilli in the blood of a suspected horse. 



The blood serum of a rabbit, when the latter has been 

 treated with red blood corpuscles of the sheep, contains an 

 antibody (hemolytic amboceptor) which will dissolve sheep 

 blood corpuscles if free complement is added. 



If, therefore, we add free complement (fresh Guinea pig 

 serum) to the blood serum of a glandered horse and then 

 add rabbit serum containing hemolytic amboceptor, this mix- 

 ture, if added to the red blood corpuscles of the sheep, will 

 leave the latter intact, because the complement that was added 

 was already fixed to the antigen by means of the glanders 

 antibodies. Now, the blood serum of healthy horses does not 

 contain these antibodies and consequently the complement 

 added to it does not become fixed, but remains active. This 

 free complement, with the hemolytic antibody, dissolves the 

 corpuscles of the blood in hetdthy horses. 



The technique of serum diagnosis by means of comple- 

 ment fixation is as follows : To a measured quantity of blood 

 serum from a suspected glandered horse add glanders antigen 

 and fresh Guinea pig serum (this contains free complement), 

 then heat at 37° C. in a thermostat for a few hours. Then add 

 serum from a treated rabbit (as explained above) and also 

 some thoroughly washed red blood corpuscles from a sheep. 

 If the red corpuscles thus added are not dissolved the horse 

 is affected with glanders. If they are dissolved the horse in 

 question is free from the disease. 



This method of diagnosis can be accurately conducted in 

 specially equipped laboratories only, and is therefore not 

 adapted for use by the regular practitioner. It is practicable, 

 however, for the latter to collect the blood of the suspected 

 horse and transmit it for examination. 



