40 INFECTION AND IMMUNITY. 



for years. "Latent" gonorrhea is frequently in- 

 fective. The urine after recovery from typhoid 

 fever may contain the bacilli for months (Pe- 

 truschky and others), and the recent study of ty- 

 phoid carriers has shown that they may discharge 

 bacilli in the stools for many years (twenty or 

 more). In some instances it has been supposed 

 that the gall-bladder is in a state of chronic in- 

 fection with the bacilli and serves as a reservoir 

 for continuous flooding of the intestines. The 

 value of the remedial measure suggested i. e.., the 

 extirpation of the gall-bladder has not yet been 

 demonstrated. We cannot leave out of mind the 

 possibility that the typhoid bacillus,, in some in- 

 stances, may become habituated to the intestinal 

 environment and multiply there; in such cases it 

 would not be necessary to assume another source 

 of replenishment. The dissemination of micro- 

 organisms by insects which have fed on infected 

 blood is apart from excretion and is considered 

 under the subject of "Insect Transmission" Chap- 

 ter VI.) . 



