PROTECTIVE INOCULATIONS 301 



intravenously they promptly die within three to six days from a 

 general infection. Inoculation experiments on hogs or feeding of 

 infected material, as shown by Kitt, Schiitz, Schottelius, and Preisz, 

 lead to the development of a typical attack of erysipelas with septi- 

 cemia. 



Protective Inoculations. The first successful attempt in protecting 

 experimental laboratory animals and hogs against erysipelas infection 

 were made by Emmerich and Mastbaum; these were followed by 

 Pasteur's protective inoculations with cultures of the bacillus atten- 

 uated for hogs by being repeatedly passed through rabbits. The 

 modern methods now universally used were worked out almost 

 simultaneously by Leclainche, Voges and Schiitz, and Lorenz. These 

 methods consist in injecting an immune serum of high value and a 

 virulent culture of the bacillus of swine erysipelas, either mixed or 

 simultaneously, in different places or at different times, i. e., first the 

 immune serum, then the culture. The immune serum is generally 

 prepared in the horse, occasionally in cattle. Horses in order to 

 furnish an immune serum of high value generally receive first intra- 

 venously 100 c.c. of a bouillon culture of virulent erysipelas bacilli. 

 It is necessary to begin with a comparatively large dose because 

 equines do not react to small doses of 5 to 50 c.c. of bouillon cultures. 

 The doses are increased in intervals of eight to ten days to 150, 200, 

 250, 300, and even to 500 c.c. In this manner a serum of high value 

 is generally obtained in about two months. When the reaction after 

 the last injection has subsided the blood is drawn, collected, and 

 treated in the usual aseptic manner and prepared for preservation by 

 the addition of 0.5 per cent, carbolic acid. Kitt, Schubert, and Pretter 

 have also prepared an antiserum in a similar manner in cattle. It is 

 claimed by some that a mixture of horse and cattle serum, a so-called 

 "double serum," is more powerful in its effect than the horse serum 

 alone, but this is denied by others. The antiserum must be tested 

 before use. The best animals for this purpose are gray house mice. 

 A good strong immune serum should, in a dose of 0.01 gram, protect 

 a mouse of 15 grams against 0.1 gram of virulent bouillon culture 

 of the erysipelas bacillus. An immune erysipelas serum from horses 

 or cattle meeting with these requirements is used in practice as follows: 



For Therapeutic Purposes in Hogs Sick with Erysipelas. A hog 

 weighing up to 100 pounds receives 10 c.c.; hogs from 100 to 250 

 pounds, 20 c.c.; hogs weighing over 250 pounds, 30 c.c. The in- 

 jection may be made at any place of the body, but the base of the 

 external ear, or, if larger amounts are used, the knee fold are generally 

 preferred. The therapeutic value of the injection is the better the 

 earlier in the course of the disease it is used. 



For Protective Purposes by the Simultaneous Method. As already 

 stated, protective inoculation may be made by the simultaneous 

 method, or with an interval between the serum and the culture 



