Passive Immunization. 387 



indicate that the streptococcus of strangles, in spite of its 

 morphological similarity, is different from the pyogenic strep- 

 tococci of man, the immunization of horses has lately been 

 undertaken with the specific streptococci of horses. The treat- 

 ment with serum obtained from horses treated by the various 

 strains of pyogenic and strangles streptococci consequently 

 gave better results. 



According to Rohr's observations, the serum injection of horses 

 affected with strangles diminishes the quantity of the profuse purulent 

 nasal discharge, the fever is reduced, and not infrequently the treatment 

 results in the absorption of the abscesses already in the stage of devel- 

 opment (the serum was subcutaneously injected in doses of 10 cc. three 

 times on the first day, and once on the second and third day). The 

 results of Jacoulet's experience with this treatment on 30 horses were 

 also favorable ; since the fever in this mode of treatment was of short 

 duration, complications and relapses were more rare, and the recovery 

 of the patient was hastened. (The daily dose amounted to from 20 to 

 30 cc. ; 80 to 100 cc. brought the development of the disease process to 

 a standstill). 



Dassonville & Vissocq produced a serum by treating horses with 

 virulent streptococci cultures, of which 20 to 30 cc. was supposed to 

 protect healthy horses against natural contact infection. By following 

 the serum injection with a subcutaneous injection of 3 to 5 cc. of viru- 

 lent cultures, it should be possible to convert the passive into an active 

 immunity. French veterinarians (Desoubry, Breton, Argoud and 

 others) obtained favorable results with this method of immunization, 

 and partly also with the serum alone. 



Jess & Piorkowski produced a strangles serum from horses by 

 treating them with cultures made from growing various strains of 

 strangles streptococci directly from the abscesses on strongly alkaline 

 media, of which 0.0005 cc. is said to protect mice against double the fatal 

 dose of virulent culture, and to agglutinate these cultures in dilutions of 

 at least 1 :100. The single dose in practice is 10 cc. or even more, which 

 if necessary may be repeated 2 to 3 times. 



The reports regarding the protective and curative action of this serum vary. 

 While Aronson in his laboratory experiments, Angerstein, Eeimers, Feuerbach and 

 also Prussian district veterinarians in practice found it without effect, according to 

 Stramnitzer it is supposed to be beneficial at the beginning of pure strangles, and 

 also to improve the general condition in advanced eases in 50 cc. doses. A favor- 

 able influence on the course of the disease was also observed by Brandt, Pflanz, 

 Franz and Otto (in 124 horses), in Hungary by Demeny & Szende; after the serum 

 inoculations the fever dropped and the inflammatory swelling disappeared rapidly, 

 mostly however after the opening of the abscesses. Likewise favorable are the re- 

 ports' of Cederberg on the serum treatment of horses affected with strangles in the 

 Danish army; the preventive inoculations however failed in several cases, and 

 the experiments of Wucherer and Wagenheuser gave similar results. 



Ruppel's strangles serum (Gurmin) is derived from horses which 

 have been treated with a mixture of strains from strangles, together 

 with a streptococcus culture made highly virulent by passages through 

 animals. It is supposed to protect mice in doses of 0.005 to 0.00025 cc. 

 against 10 to 100 times the fatal dose of virulent culture. In 36 out of 

 44 horses affected with strangles it is supposed to have given a pro- 

 nounced curative result, in daily doses of 20 to 50 cc, while in healthy 

 horses it afforded a protective action. 



