70 TYPHOID FEVER 



develop on litmus gelatine plates or on gelatine containing some 

 other color affected by the colon bacillus in a similar manner. The 

 number of red colonies developing on such plates is taken as an indi- 

 cation of the extent to which the water carries fecal contamination. 

 If fecal matter from healthy people finds its way into the water that 

 from those infected with the typhoid bacillus may, and the only safe 

 procedure is to condemn all waters bearing fecal matter. This does 

 not mean that the colon bacillus in any of its varieties will cause 

 typhoid fever. 



Nothing like typhoid exists so far as we know in any of the lower 

 animals. Moreover, with the possible exceptions to follow, all 

 attempts to induce a chronic fever with the typhoid lesions in animals 

 by inoculation with the specific bacillus have failed. Injected in large 

 enough doses it kills, but without infection. The dead bacillus does 

 the same thing. This shows that the cellular substance contains a poi- 

 son, but this is true of all bacteria, both pathogenic and non-pathogenic. 

 Grunbaum claims to have developed typhoid fever in a chimpanzee 

 and Weinberg reports positive results with apes infected with certain 

 intestinal parasites, which inflict on the mucous membrane wounds 

 through which the bacillus find entrance. While our domestic animals 

 do not become infected with this bacillus, they may bear it from place 

 to place on their bodies or distribute it in their excretions. Several 

 cases of accidental laboratory infection and a few acquired inten- 

 tionally have occurred. These demonstrate the pathogenicity of the 

 bacillus for man. 



Sources of Infection. It is true of typhoid fever, as it is of 

 Asiatic cholera, that every case of infection is due to the transference 

 of the fecal matter of the infected either by a short or a long circuit, 

 to the alimentary canal of another, There is, however, this important 

 difference ; cholera is widely disseminated only at certain times and in 

 certain places, while typhoid is well-nigh ubiquitous. Up to the pres- 

 ent time there is no part of the world absolutely free from this disease 

 for any great length of time. In one sense typhoid is a filth disease 

 inasmuch as it is scattered through the excretions of the human body, 

 especially in the urine and feces. No wonder that it was thought that 

 typhoid may originate de novo. Now, we know that this is not true, 



