TYPHOID BACILLUS 373 
The isolation and identification of typhoid bacilH from the feces is 
by no means proof that the case under consideration is typhoid fever; 
the patient may be a carrier. 
Techniqiie of Isolation of Typhoid Bacilli from Feces.— A thin uniform 
emulsion of feces suspected to contain typhoid bacilli is made in 0.1 
per cent glucose broth and incubated, if time permits, for one hour 
at 37° C. 
The emulsion is best made by repeatedly running a rather heavy 
platinum needle through the fecal mass to insure a representative 
sample, then removing the adhering fecal mass into the tube of culture 
medium. The process is continued until the desired density of 
bacteria in the broth tube is attained. Incubation of one hour permits 
of a slight development of all the organisms; it particularly acclimatizes 
the typhoid bacilli to artificial media. The emulsion is then spread 
with a bent steri'e glass rod on the surface of lactose agar containing 
the Andrade indicator, previously prepared in large Petri dishes.^ 
The Petri dishes after inoculation are inverted and placed in the 
incubator at 37° C. and examined eighteen to twenty-four hours 
later for clear, colorless, transparent colonies which rarely attain 
a diameter exceeding 2 mm. These colonies are transferred to 0.1 
per cent glucose broth and after incubation for eighteen to twenty- 
four hours at 37° C. are mixed with a high potency antityphoid serum 
and examined for agglutination. 
Rapid Method of Isolating Typhoid Bacilli.'-— It is frequently pos- 
sible to identify typhoid bacilli (and paratyphoid and dysentery 
bacilli as well) in feces within twenty-four hours by taking advantage 
of the microscopic agglutination method with a high potency serum in 
the following manner: Lactose agar Andrade plates are inoculated 
as indicated above and incubated at 37° C. for fifteen to eighteen 
hours. Typical colonies are removed entire to small test-tubes con- 
taining 1 cc. of 0.1 per cent glucose broth which have been kept at 
incubator temperature. Incubation of these infected tubes for one 
to two hours almost invariably gives sufficient numbers of organisms 
to make a microscopic agglutination. A confirmatory cultural diag- 
nosis may be obtained by the inoculation of small tubes of semi-solid 
media and milk with the remainder of the broth culture. This method 
differs from the one usually employed merely in the small amount of 
broth used, which requires less bacteria to produce turbidity, and in 
the fact that the growth is practically continuous from the isolation 
medium to the tube, the broth being warmed to the body temperature 
at the start. Taking advantage of these factors cuts down the time 
required for diagnosis nearly twenty-four hours. 
(6) Serological Dl\gnosis.— The blood serum of patients who 
have recovered from a typical attack of typhoid fever contains ele- 
ments which give specific reactions with the typhoid bacillus or its 
1 For preparation and use of this medium, see page 229 and supra. 
- Kendall and Day: Jour. Med. Res., 1911, 25, 95. 
