1368 THE ENTEROIDEA GROUP OF TROPICAL FEVERS 



centre of gall-stones removed by surgical operations, tend to 

 support the view that the gall-bladder is, at all events in some 

 cases, the home of the B. typhosus in a chronic carrier. Fornet, 

 in 1909, has, however, stated that he believes the bacilli found 

 in the faeces of a carrier are not descended from those which caused 

 the attack of fever, but are derived from a reinfection which does 

 not produce any clinical symptoms, because the human host has 

 attained a tolerance to the parasite, which therefore leads a sapro- 

 phytic existence, presumably in the lumen of the intestines. 



The discharge of bacilli by means of the faeces appears to be inter- 

 mittent, and not continuous, which is a most important fact, as 



ff*EEf<y ZO 27 ^ II IS 15 I 6 15 22 19 5 IE 19 ZG 3 10 17 Z4- 31 

 ENDING) JUNE JULY AUGUST SEPTEMBER OCTOBER 



Fig. 658. — Curves illustrating Number of Flies and Gases of Enteric 

 Fever. (After C. J. Martin.) 



the duration of the possible intermission is not positively known, 

 and therefore it is difficult to say definitely when the carrier is really 

 clear of the parasite. 



The reason why women are more commonly carriers than men is 

 said to be due to the loss of resisting power brought about by the 

 decrease in the alexins of the blood during the menstrual and 

 puerperal periods, and this is supported by the fact that, while the 

 incidence of enteric fever is greater in females from fifteen to twenty 

 years of age, the possibility of becoming a chronic intestinal carrier 

 increases steadily from the fifteenth to the forty-fifth year. A 

 more probable reason seems to us to be that women are more liable 

 than men to affections of the gall-bladder. 



