INOCULATION INTO LOWER ANIMALS. 317 



but with limited success. Fatal results without the ap- 

 pearance of the typical pathological changes have fre- 

 quently followed these attempts, but in most cases they 

 could easily be traced to the toxic, 1 rather than to the 

 truly infective 2 action of the materials introduced into 

 the animals. 



The most successful efforts for the production of the 

 typical typhoid lesions in lower animals are those re- 

 ported by Cygnseus. By the introduction of the typhoid 

 bacilli into the tissues of dogs, rabbits, and mice he was 

 able to produce in the small intestines conditions that 

 were histologically and to the naked eye analogous to 

 those found in the human subject. 



Of a number of experiments made by the writer with 

 the same object in view, only one positive result fol- 

 lowed the introduction of typhoid bacilli into the circu- 

 lation 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 methods, but were also demonstrated micro- 

 scopically in their characteristic clumps in sections of 

 the organ. 



In connection with the inoculation of animals with 

 the bacillus typhi abdominalis, observations of a most 

 important nature have been made by Sanarelli 3 upon 

 the artificial induction of susceptibility to its pathogenic 

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



1 Toxic Poisonous results not necessarily accompanied by the growth of 

 organisms throughout the tissues. 



2 Infective or septic Poisoning of the tissues as a result of the growth of 

 bacteria in them. 



s Sanarelli : Annales de 1'Institut Pasteur, 1892, tome vi. 



