SWINE ERYSIPELAS GROUP 247 



urticaria of the disease. The use of this method has led to varied 

 results in different countries. Voges and Schiitz have modified 

 the Pasteur vaccine method by doing away with the Vaccine II., 

 as they found the blood still contained bacilli at the time of the 

 second injection, and concluded the latter, therefore, useless. 

 It seems that a satisfactory immunization of the hog against the 

 disease cannot be accomplished by injections of the killed organ- 

 isms. 



Passive Immunization. Emmerlich and Mastbaum, in 1891, 

 described a method of preparing an immune serum which would 

 protect animals against the disease. Their method was impractical 

 in some respects, and was superseded by the method of Lorenz, and 

 this by those of Leclainche, Voges and Schiitz, and Lange. The 

 antiserum is prepared by the intravenous injection of virulent bouil- 

 lon cultures into the horse. Usually 100 c.c. constitutes the initial 

 injection, and is followed at intervals by larger amounts up to 

 500 c.c. The injection produces a rise in temperature, and other 

 reactions that disappear in twenty-four to forty-eight hours. The 

 immune blood is drawn, and the serum used for passive immuniza- 

 tion of swine. It is prepared on a large scale in several institutes 

 in Europe, and is used extensively. Cattle and even buffalo are 

 sometimes used instead of the horse in the preparation of the serum. 

 Prettner claims that the use of cattle immune serum confers a more 

 lasting immunity than that of the horse. Schreuber and Schubert 

 studied the question of multiplicity of amboceptors, and came to 

 the conclusion that a mixture of immune sera from horses and 

 cattle would give a greater variety of amboceptors specific for the 

 organism. A mixture of this kind is termed " double serum " 

 (German, Rotlauf Doppelserum). The double serum has not 

 proved in practice to be of any greater value than the serum from 

 the horse alone. The immune serum is usually standardized by 

 the use of the mouse, commonly by the method of Lorenz. A 

 serum suitable for use should immunize a mouse in doses of 0.01 

 gm. per 10 gm. of weight, against injection with 0.01 gm. of a 

 virulent culture. Lorenz used mice weighing uniformly 15 gm. 

 as a standard, and such a serum is said to have a titer of 0.015 gm. 

 (mouse). Marx has modified the technic of Lorenz somewhat, 

 but the principle is the same. Leclainche has advised the use of 



