PRINCIPLES OF VETERINARY SURGERY 399 



exposed six minutes to 55 degrees C. A small portion of 

 exudate taken from a phlegmon that killed a cat was ex- 

 posed to a temperature of 55 degrees C, and then inocu- 

 lated into another cat. The latter became refractory to the 

 inoculation of blood from a dead horse. From these facts, 

 Semmer concludes that the bacteria of septicaemia intro- 

 duced into the organism opposes the multiplication of bac- 

 teria of the same genus in the organism previously impreg- 

 nated. 



From numerous researches that have followed those of 

 Semmer it results that immunity can be conferred by three 

 different methods : 



1. By intra veneous inoculation. 



2. By inoculation with attenuated virus. 



3. By inoculation with toxins. 



1. By Intraveneous Inoculation (Chauveau and Air- 

 loing). — The professors from Lyons obtained, in the ass, 

 the most beautiful examples of immunity by introducing 

 strong doses of the virus into the veins at different periods. 

 If a subject thus vaccinated, is inoculated subcutaneously 

 with one-half to one cubic centimeter of virulent serum, an 

 abscess will form at the seat of inoculation, but gaseous 

 gangrene will not supervene. In the dog and sheep im- 

 munization by this procedure is more difficult to obtain. 



2. By Inoculation with Attenuated Virus. — This 

 method, reported by Cornevin, is not susceptible of giving 

 sensible results beyond an immunity that disappears in 

 twenty-four hours. 



3. By Inoculations with Toxins. — In 1887, Chamber- 

 land and Roux succeeded in assuring immunity by intra- 

 peritoneal injections of perfectly pure cultures of the septic 

 vibrion exposed to a temperature of 104 to no degrees C. 

 In eight days each cavy received in three times, one dose 

 of ninety cubic centimeters. The injection was followed 



