SEPTIC^MIA IN RABBITS. 375 



ceedingly instructive, not only as illustrating the 

 value of protective inoculations against septicae- 

 mia, but as showing the importance of selecting 

 rabbits not previously experimented upon for 

 experimental studies relating to the etiology of 

 infectious diseases. 



It should also be remembered by those who 

 undertake experimental investigations of this na- 

 ture, that accidental inoculation may occur, or 

 that a rabbit may suffer a non-fatal attack as the 

 result of contact with other septicsemic animals, or 

 from being placed in infected cages. Davaine 

 long since recorded the fact that spontaneous 

 septicaemia occurred among his rabbits from this 

 cause ; and the writer has also lost a number of 

 rabbits in this way, while others of the same lot 

 recovered after a brief illness, and subsequently 

 proved to be protected from the lethal effects of 

 septic virus. 



It is not impossible that, in man, a certain 

 immunity from infectious diseases, the epidemic 

 prevalence of which depends upon the presence 

 of decomposing organic material in the infected 

 localities, e.g., cholera, yellow fever, diphtheria, 

 may be acquired by exposure to septic material 

 which lacks the infectious character ; i. e., that a 

 tolerance is established to the effects of the chem- 

 ical poison or poisons which are evolved as a result 

 of the vital activity of both pathogenic and non- 

 pathogenic bacteria. It has frequently been noted 

 that grave-diggers, those who clean sewers, and 



