348 BACTERIOLOGY. 



followed the introduction of typhoid bacilli into the 

 circulation of rabbits. In this case the ulcer in the 

 ileum was macroscopically and microscopically identical 

 with those found at autopsy in the small intestine of the 

 human subject dead of this disease. The typhoid bacilli 

 were not only obtained from the spleen of the animal by 

 culture method, but were also demonstrated microscopi- 

 cally in their characteristic clumps in section of the organ. 

 In connection with the inoculation of animals with 

 bacillus typhi abdominalis observations of a most im- 

 portant nature have been made by Sanarelli^ upon the 

 artiticial induction of susceptibility to its pathogenic 

 action. He found that rabbits, guinea-pigs, and mice 

 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 prodigiosus, 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 resulted in from twelve to forty-eight hours, with 

 the most conspicuous pathological alterations in the 

 digestive tract, and particularly in the small intestine. 

 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 consid- 

 ered as analogous to a similar condition that may occur 

 in man from the absorption of abnormal products of 

 fermentation from the intestinal canal — an auto-intoxi- 



1 Sanarelli : Annates de I'Instltut Pasteur, 1892, tome vi. 



