Rouget, Rothlauf. Red Fever of Swine, etc. 21 



Pathogenesis. The bacillus is pathogenic to swine, rabbits, 

 white mice, house mice, white rats, pigeons and sparrows. Field 

 mice, guinea pigs and chickens are immune. 



Mice and pigeons take the disease most certainly, and die in 

 three days to five, the whole body swarming with bacilli. Rab- 

 bits take the disease less certainly or rapidly, inoculation in the 

 ear causing first an erysipelatoid inflammation and recovery with 

 immunity often takes place. 



Immunization. When inoculated continuously from rabbit to 

 rabbit it encreases its potency for that animal, which it comes to 

 kill in 24 to 48 hours, but in the same ratio it loses its virulence 

 for swine upon which it can then be inoculated without danger to 

 their life. 



It was on this basis that Pasteur and Thuillier established in 

 1883, their preventive inoculation for rouget. The method has 

 been most extensively employed in Europe, and where intelli- 

 gently employed has prevented this disease. From the labora- 

 tory at Buda-Pest alone, there was sent out in one year material 

 for 249,816 swine. 



The objections to the method are : the danger of mistaking 

 hog cholera and swine plague respectively for rouget, as the 

 rouget mitigated germ would be in no sense protective against 

 these ; and the danger of spreading the germs of rouget in fresh 

 localities and thus introducing a new plague instead of controlling 

 and preventing an old one. In the Baden experiments 5.4 per 

 cent of inoculated pigs died, and of 118 unprotected pigs exposed 

 to them 62 per cent, contracted the disease and one died. In 

 France and Hungary, on the other hand, i to 1.45 per cent, died 

 of the operation, instead of 20 per cent, when the disease was 

 contracted in the ordinary way. 



It is held that the danger lies largely in the inoculation of very 

 young pigs, and Nocard advises to operate only on those of four 

 months and upward. 



The danger of spreading the germ by inoculation may be the more 

 easily guarded against, considering that it is very destructible by 

 disinfectant agents (heat, dryness, cold, chloride of lime, quick 

 lime"), and that it does not readily survive in a locality, where it 

 cannot find a constant succession of victims. Yet the practice 

 ought to be confined to herds exposed to infection, and under 

 special precautions, as regards the exposure of other herds. 



