420 A MANUAL OF BACTERIOLOGY 



after freezing with liquid air, and found it be to very toxic 

 to guinea-pigs by intra-peritoneal, and to rabbits by 

 intra-venous, inoculation. The writer found that cultures 

 of the Bacillus typhosus do not give the " diazo " reaction. 

 Survival of the typhoid bacillus in the body. The typhoid 

 bacillus usually disappears from the body when con- 

 valescence is well established, but occasionally bacilli 

 may persist in the spleen for weeks, in the gall-bladder for 

 years, and in suppurative lesions for six years or more. 

 Foster and Kayser obtained pure cultures from the gall- 

 bladders of seven out of eight cases, and in 2 per cent, of 

 the cases this " cholecystitis typhosa " becomes a chronic 

 process, and typhoid bacilli may be discharged into the 

 bowel for long periods, perhaps indefinitely. Dean l 

 found bacilli to be still present in a patient who had 

 had enteric fever twenty-nine years previously. Such 

 " typhoid carriers " have been the subject of much 

 investigation. 2 A. and J. Ledingham record three 

 instances met with in an asylum in which mysterious 

 cases of typhoid had occurred thirty-one cases during 

 fourteen years. Davies and Walker Hall 3 relate similar 

 outbreaks, the carrier in this case being a woman who 

 had suffered from enteric fever in 1901, milk serving as 

 the vehicle of transmission, and a number of other 

 instances have been recorded. Three-fourths of the 

 carrier cases are women (and three-fourths of the cases of 

 gall-stones occur in women), and usually the serum of the 

 carriers gives a marked agglutination reaction, and their 

 stools frequently contain such large numbers of typhoid 

 bacilli that these largely replace the natural bacterial 

 flora of the intestine and may often be recovered from the 



1 Brit. Med. Journ., 1908, vol. i, p. 562. 



2 See Ledingham, Rep. Med. Off. Loc. Gov. Board for 1909-10 ( Bibliog. ); 

 ibid, for 1912-13, p. 336. 



9 Proc. Roy. Soc. Med., vol. i, 1908, Epidemiolog. Sect., p. 175. 



