300 BACTERIOLOGY. 



appearance of the typical pathological changes have fre- 

 quently followed these attempts, but in most cases they 

 could easily be traced to the toxic/ rather than to the 

 truly infective^ 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 

 reported 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 

 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 methods, but were also demonstrated 

 microscopically 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 recently been made upon the 

 artificial induction of susceptibility to its pathogenic 

 action by Sanarelli.' He found that rabbits, guinea- 

 pigs, and mice could be rendered susceptible to in- 



' 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. 



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



