2 BULLETIN 70, U. S. DEPARTMENT. OF AGRICULTURE. 



It is unfortunate, however, that the demonstration of immune 

 bodies does not indicate the degree of immunity in the animals. 



We may obtain in glanders immunization an agglutination value 

 of 1 to 5,000 or over or a complement fixation with 0.02 of a cubic 

 centimeter of serum which may continue for a period of several 

 months, yet this same animal, which apparently is supplied with a 

 great amount of immune bodies, can be readily infected with glanders 

 bacilli. Therefore, in tests undertaken for establishing the degree 

 of immunity against glanders in the horse, it is necessary to expose 

 the injected animals to an infection such as occurs under natural 

 conditions. Observations of such animals as to the clinical appear- 

 ance of the disease and periodical ophthalmic tests with mallein are 

 the methods by which the most accurate results of the immunization 

 tests can be obtained. Serum tests in these cases are of little value, 

 as they invariably demonstrate immune bodies or antibodies in the 

 immunized animals, and since even small quantities of mallein 

 injected into a horse are sufficient to produce antibodies which remain 

 for 3 or 4 weeks. 



PREVIOUS RESULTS WITH VARIOUS IMMUNIZING AGENTS. 



Curative results from mallein were reported by Leclainche, Hueppe, 

 Nocard, Johne, and WladimirofT, while its immunizing value against 

 glanders was studied by Schindelka, McFadyean, and Semmer, but 

 the results were unsatisfactory. Taking into consideration the litera- 

 ture at our command and drawing conclusions from the results ob- 

 tained, it appears that mallein possesses very little immunizing value 

 and no great benefit can be expected from its use as a curative 

 agent. 



Other investigators attempted to immunize horses and other 

 animals against glanders with the use of killed glanders bacilli and 

 the literature contains some favorable results from this method of 

 immunization. The preparations which were employed for this pur- 

 pose were in most instances suspensions of glanders bacilli killed by 

 heat. Of the various products which have been prepared and are at 

 the present time used to a limited extent for the immunization of 

 glanders, "farase," so termed by Levy, Blumenthal, and Marxer, 

 gives apparently the best results. It is prepared by killing glanders 

 bacilli with 80 per cent glycerin or 10 per cent urea. The bacilli are 

 then dried and the substance is used in that condition for the immu- 

 nization. It does not contain living bacteria. Favorable results were 

 obtained with farase by Bautz and Machodin, and by Dediulin. The 

 results of Dediulin are probably the most remarkable, since he reports 

 that on an estate where previous to immunization 276 glandered ani- 

 malshad been destroyed, he injected 303 animals and after one year and 



