TYPHOID BACILLUS 331 



percentage of cases, however, the organisms may be excreted in the 

 urine, or more commonly in the feces, for months or even years after 

 recovery. Thus, Philipowicz 1 isolated typhoid bacilli from a case 

 of cholecystitis who had had typhoid fever thirty-eight years previous 

 to the operation. In this case very few typhoid bacilli were present 

 in the feces, and it is probable that the few organisms were over- 

 whelmed by the intestinal bacteria during their passage through the 

 intestinal tract. From 1 to 4 per cent, of all typhoid cases which 

 recover appear to become fecal typhoid carriers; a smaller percentage 

 become urinary carriers. No history of typhoid fever can be elicited 

 from some of these carriers, and the supposition is that either the 

 carrier had in the past a mild unrecognized case, or less commonly 

 that the organism had become acclimatized in the intestinal tract 

 without inducing disease. Many carriers give a positive Widal reaction. 



The residual focus of typhoid bacilli in carriers is usually the gall- 

 bladder and the ducts of the gall-bladder, less commonly the urinary 

 bladder. From the gall-bladder the organisms pass in irregular num- 

 bers into the intestinal tract; occasionally in sufficient numbers to be 

 demonstrable in the feces. A considerable proportion of operations 

 for cholecystitis and gall-stones the greater majority being among 

 women give positive typhoid cultures when the contents are examined 

 bacteriologically. 



Pathogenesis in Animals. All animals, except possibly anthropoid 

 apes, are naturally immune to typhoid fever, and inoculation of old 

 laboratory cultures of typhoid bacilli into laboratory animals is 

 usually without noteworthy effect; virulent cultures of typhoid bacilli, 

 particularly those produced by repeated passage through laboratory 

 animals, may produce peritonitis and death when they are introduced 

 into the animals by the intraperitoneal route. The infection, how- 

 ever, does not resemble typhoid fever. The lesions observed post- 

 mortem are marked congestion of the abdominal organs, particularly 

 the spleen, kidneys and liver, as well as involvement of the intestinal 

 lymph apparatus; the thoracic organs are less involved as a rule. 



The organisms may be recovered from the peritoneal fluid, the blood 

 stream, and from various abdominal organs. Gay and Claypole 2 

 have succeeded in inducing with great regularity the carrier state in 

 rabbits by injecting into them typhoid bacilli which have been grown 

 for several successive transfers on agar overlaid with fresh defibrinated 



1 Wien. klin. Wchnschr., 1911, 1802. 



2 Arch. Int. Med., December, 1913. 



