TFPHOID INOCULATION IN ANIMALS. 301 



fection by this organism by injecting into them the 

 products of growth of certain saprophytes — -proteus 

 vulgaris, bacillus prodigiosus, and bacterium coli com- 

 mune — and that by whatever means the animal was sub- 

 sequently inoculated with fresh cultures of the typhoid 

 bacillus, either into the circulation or into the perito- 

 neal cavity, death resulted 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 recovered 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 sim- 

 ilar condition that may occur in man from the ab- 

 sorption of abnormal products of fermentation from 

 the intestinal canal — an auto-intoxication that so re- 

 duces 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 ' 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, grad- 

 ually 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 



1 Alessi: Centralblatt fUr Bakteriologie u. Parasitenkunde, 1894, Bd. xv., 

 No. 7, p. 228. 



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