308 



BACILLI PATHOGENIC IN ANIMALS. 



Practical 

 value of the 

 protective 

 inoculation. 



animals has also been tested. Besides some indifferent 

 bacteria mixed with them, both authors found chiefly 

 the characteristic erysipelas bacilli, and they were able 

 to convince themselves by experiments that these organ- 

 isms were as a matter of fact attenuated as regards the 

 virulence of their action on swine ; in like manner they 

 were able to ascertain that the pigs inoculated with 

 these vaccines, and which, after being ill, had again 

 recovered, were immune against inoculation with virulent 

 material. Thus the accuracy of Pasteur's experiments, 

 and the possibility of attenuation and protective inocu- 

 lation for swine erysipelas, is proved. This result was 

 a priori not improbable, as Loeffler had formerly shown 

 that the bacilli of mouse septicaemia, which so much 

 resemble the erysipelas bacillus, cause a mild disease in 

 rabbits, as the result of which these animals are rendered 

 completely immune; and as also it was known that 

 swine erysipelas belongs to the class of diseases which 

 do not recur, one attack protecting against a later 

 infection. 



Nevertheless the result of the vaccination experiments 

 carried out in large numbers in Baden cannot be re- 

 garded as being particularly favourable from a practical 

 and economic standpoint. Of 119 animals inoculated, 

 6, or 5 per cent., died of erysipelas as the result of the 

 inoculation, while the average loss from the ordinary 

 disease is at most only 2 per cent. ; however, the animals 

 which died as the result of inoculation were, on account 

 of their youth, of much less value than the animals 

 which died of erysipelas. It was also ascertained that 

 the animals which were rendered ill by the inoculation 

 were able to infect other animals with the fatal disease ; 

 and, finally, we do not as yet know whether the inocu- 

 lated swine are protected against the natural infection. 

 From these considerations it is evident that the final 

 judgment as to the practical value of Pasteur's protec- 

 tive inoculation must be deferred till more accurate 

 experimental evidence has been obtained. 



Klein has claimed the discovery of the erysipelas bacillus, 

 )mt from his statements that these bacilli may be confounded 



