318 BACTERIOLOGY. 



could be rendered susceptible to infection by this organ- 

 ism by preliminary injections into them of the products of 

 growth of certain saprophytes proteus vulgaris, bacillus 

 prodigiosuSj and bacterium coli commune and that by 

 whatever means the animal was subsequently inoculated 

 with fresh cultures of the typhoid bacillus, either into 

 the circulation or into the peritoneal cavity, death re- 

 sulted in from twelve to forty-eight hours, with the most 

 conspicuous pathological alterations in the digestive tract, 

 and particularly in the small intestines. In these cases 

 the infection is general and the organisms may be recov- 

 ered from the blood and internal organs. It is the 

 opinion of Sanarelli that the toxic conditions produced 

 by the preliminary injections of the products of growth 

 of the saprophytic organisms may be considered as 

 analogous to a similar condition that may occur in man 

 from the absorption of abnormal products of fermenta- 

 tion from the intestinal canal an auto-intoxication that 

 so reduces the resistance of the individual as to render 

 him susceptible to infection by the bacillus of typhoid 

 fever, should it gain access to his alimentary tract. 



More recently it was found by Alessi 1 that rats, 

 guinea-pigs, and rabbits, when permitted to breathe the 

 gaseous products of decomposition from the contents of 

 a cesspool, or from other decomposing matters, gradually 

 became susceptible to infection by the typhoid bacillus. 

 After an exposure of from five to seventy-two days in 

 the case of rats, seven to fifty-eight days in the case of 

 guinea-pigs, and three to eighteen days in the case of 

 rabbits, the resistance of the animals was so diminished 

 that inoculation with relatively small amounts of cul- 



1 Alessi : Centralblatt fur Bakteriolgie u. Parasitenkunde, 1894, Bd. xv., No. 

 p. 228. 



