652 PATHOGENIC MICROORGANISMS 



considerable concentration with 2-per-cent glucose agar and pouring 

 plates. 



The writers in hospital work have had equally good results with the 

 bile medium and with broth in flasks, rather less uniform but still satis- 

 factory results with the plating method. In general it may be said that 

 any one of these methods carried out with reasonable accuracy may be 

 satisfactorily employed. 



Typhoid Bacilli in the Stools. The examination of the stools for 

 typhoid bacillus is performed for diagnostic purposes chiefly in obscure 

 cases. It may, furthermore, furnish information of great hygienic 

 importance. Thus Drigalski and Conradi 26 have succeeded in isolating 

 typhoid bacilli from the stools of ambulant cases so mild that they 

 were not clinically suspected. It is by means of such examinations 

 that the so-called typhoid-carriers are detected, a problem which is 

 considered at length in the section dealing with epidemiology. Such 

 cases have been known to harbor the bacilli for periods as long as 

 several years. 



The examination itself is fraught with difficulties, owing to the pre- 

 ponderating numbers of colon bacilli found in all feces and the diffi- 

 culty of isolating the typhoid bacilli from such mixtures. 



Reviewing the data collected by a number of investigators, it 

 seems probable that the bacilli do not appear in the stools, at least 

 in numbers sufficient for recognition, much before the middle of the 

 second week, or, in other words, as pointed out by Hiss, about the 

 time that the intestinal lesions are well advanced and ulceration is 

 occurring. Thus Wiltschour 27 could not determine their presence 

 before the tenth day; Redtenbacher, 28 in reviewing the statistics, states 

 that in a majority of cases the bacilli first appear toward the end of the 

 second week, and Horton-Smith 29 could not find the bacilli before the 

 eleventh day. Hiss, 30 in an investigation of the same subject, obtained 

 the following results: 



First to tenth day, inclusive, twenty-eight cases examined; typhoid 

 bacilli isolated from three; percentage of positive cases 10.7 per cent. 



Eleventh to twentieth day, inclusive, forty-four cases examined; 

 typhoid bacilli from twenty-two; percentage of positive cases 50 per 

 cent. 



26 Drigalski and Conradi, Zeit. f . Hyg., xxxix, 1902. 



27 Wiltschour, Cent. f. Bakt., 1890. 



28 Redtenbacher, Zeit. f . klin. Med., xix, 1891. 



29 Horton-Smith, Lancet, May, 1899. 



30 Hiss, Med. News, May, 1901. 



