360 A MANUAL OF BACTERIOLOGY 



a number of other instances have been recorded. Three- 

 fourths of the 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 stools by simple plating. Firth's statistics give 

 an idea of the frequency of the development of the carrier 

 state. Of 1229 cases of enteric fever among the British 

 troops in India bacteriologically examined, 13 cases of 

 chronic carriers and 13 cases of temporary carriers were 

 detected. Obviously the typhoid carrier is a source of 

 serious risk to the community, and mysterious outbreaks 

 of enteric fever, ascribed by some in the past to a " de 

 novo " origin of the specific organism, become explicable. 

 Typhoid convalescents should be bacteriologically examined 

 before discharge from hospital and the negative cases 

 may with reasonable safety be allowed to resume their 

 civil life (Ledingham). The typhoid bacillus may occur 

 in the contents of ovarian cysts, usually causing suppura- 

 tion, and may survive for months twelve in a case 

 recorded by Taylor l after the attack of typhoid. 



Survival of the typhoid bacillus outside the body. The 

 Bacillus typhosus has been isolated in a few instances from 

 WATER SUPPLIES which have become infected, and have 

 given rise to epidemics, as in the case of the Lincoln 

 epidemic in 1905. 2 This is the exception, however, and 

 the isolation of the typhoid bacillus from an infected water 

 is a very difficult matter on account of the fact that the 

 bacillus may have died out before the investigation is 

 commenced, that it is generally in a small minority and 

 admixed with numbers of coliform organisms, and that 



1 Journ. Obstet. and Gyncecol. Brit. Empire, November 1907. 



2 Rep. Med. Off. Loc. Gov. Board for 1905-06. 



