414 PATHOGENIC MICROORGANISMS 



Prophylactic measures in typhoid fever, therefore, should begin 

 with the isolation of the patient and the disinfection of excreta, dis- 

 charges, linen, and aU utensils which have been in contact with the 

 patient. The bacilli leave the body chiefly in the feces and the urine 

 and the dangers of contamination, by these substances, of all objects in 

 immediate contact with the patient are considerable. Excreta should 

 therefore be either mixed with boiling water or chemically disinfected, 

 preferably by means of thoroughly mixing with carbolic acid, lysol, or a 

 solution of freshly slaked lime, and, if possible, destroyed hy burning. 

 Linen, tableware, and eatiug utensils should be soaked in similar 

 solutions and boiled. The observance of such measures, furthermore, 

 should not be discontinued until bacteriological examination has 

 demonstrated the absence of the bacilli from feces and urine. Disre- 

 gard of this last precaution may well be one of the main causes of the 

 endemic persistence of the disease in large cities — especially considered 

 in the light of our recent knowledge of "typhoid carriers" in whom 

 chronic infection of the gall-bladder leads to the discharge of the bacilli 

 in the feces for months and even years after the cessation of symptoms. 



It can hardly be doubted, at the present day, that tj'phoid fever, in 

 the large majority of cases, is transmitted by the agency of water. In 

 an analysis of six hundred and fifty typhoid epidemics Schiider ' found 

 four hundred and sixty-two reported, upon reasonable evidence, as orig- 

 inating from water. The technical difficulties attending the isolation 

 of typhoid bacilli from contaminated water have prevented actual 

 bacteriological proof in most epidemics; nevertheless, indirect evi- 

 dence of pollution of the suspected water-supply, correspondence of the 

 distribution of this supply with that of the disease, and reduction of 

 typhoid morbidity upon the substitution of an uncontaminated supply 

 are sufficiently convincing to remove reasonable doubt. Added to this is 

 our knowledge, from the experiments of Jordan, Russell, and Zeit ^ and 

 others, that typhoid bacilli may remain alive in natural waters for as 

 long as five days. That the bacilli may survive freezing for as long as 

 three months has been demonstrated by Prudden, and dangers of in- 

 fection from this source are therefore considerable. 



Next to water, the most important source of typhoid fever is found 

 in contaminated milk. In the statistical summary by Schiider,' quoted 

 above, one hundred and ten of the four hundred and sixty epidemics 



^Schiider, Zeit. f. Hyg., xxxviii, 1901. 



'' Jordan, Russell, and Zeit, Jour, of Inf. Dis., 1, 1904. 



3 Schiider, loc. cit. 



