TYPHOID BACILLUS 335 



Typhoid bacilli are found in the peripheral blood of a large percen- 

 tage of typical cases of typhoid fever during the first week of the 

 clinical disease. The organisms are found less frequently in the later 

 stages. The statistics reported by Coleman and Buxton, 1 covering 

 1137 cases, show this clearly. 



Positive, 

 Cases. per cent. 



First week of clinical disease 224 89 



Second week of clinical disease 484 73 



Third week of clinical disease ....... 268 60 



Fourth week of clinical disease 103 38 



Fifth week of clinical disease 58 26 



The organisms have also been isolated from rose spots (which 

 appear as a rule early in the clinical course of the disease) by Richard- 

 son and others. From these observations typhoid fever may be 

 regarded primarily as a bacteremia. 2 It should be remembered, how- 

 ever, that the organisms are destroyed in the blood stream by specific 

 lysins, and that their presence in the circulating fluids of the body 

 are partly caused by an overflow of organisms from foci in the spleen 

 and other organisms. 



Method of Collecting Blood. The skin of the elbow is thoroughly 

 cleansed as for a surgical operation, a tourniquet is applied, and a 

 large hypodermic needle is introduced into a vein, preferably the 

 median basilic. From 5 to 15 c.c. of blood are removed, discharged 

 at once into a flask containing 150 to 250 c.c. of dextrose broth (0.1 

 per cent.), and mixed thoroughly before clotting takes place. This 

 considerable dilution of the blood is important, partly because clotting 

 takes place more slowly and thus favors the escape of the organisms 

 into the broth, and also because it dilutes the lysins which are usually 

 present in the blood of typhoid patients. It is necessary to reduce 

 the concentration of lysins, for lysins dissolve typhoid bacilli. Incu- 

 bation of the culture at 37 C. for twenty-four hours usually results 

 in a growth of bacteria in which the specific organisms are present, 

 either alone or mixed with skin cocci. 



Coleman and Buxton 3 recommend an ox bile glycerin peptone 

 medium for the isolation of typhoid bacilli. The medium as prepared 

 by them has the following composition: Ox bile, 900 c.c.; glycerin, 

 100 c.c.; peptone, 20 grams. This is sterilized in the autoclave and 



1 Am. Jour. Med. Sc., 1907, cxxxiii. 



2 Brion and Kayser, Deut. Arch. f. klin. Med., 1906, Ixxxv, 552. Coleman and 

 Buxton, Jour. Med. Research, 1909, xxi, 83. Kolle and Hetsch, Experimentelle Bakt. 

 und. Infektionskrank., 1911, 3ed., i, 250, 



3 Loc. cit. 



