338 THE ALCALIGENES DYSENTERY TYPHOID 



SECONDARY CASES INFECTED FROM PRIMARY CASES. 



First week of incubation period 33 



Second week of incubation period 150 



First week of disease 1S7 



Second week of disease 158 



Third week of disease 116 



Fourth week of disease 59 



Fifth week of disease 34 



Sixth week of disease 22 



Seventh week of disease 14 



Eighth week of disease 16 



Ninth week of disease 15 



The isolation and identification of typhoid bacilli from the feces 

 is by no means proof that the case under consideration is typhoid fever; 

 the patient may be a carrier. 



Technic 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, dextrose 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. 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 sterile glass rod on the surface of Endo medium previously 

 prepared in large Petri dishes. 1 The Petri dishes after inoculation 

 are inverted and placed in the incubator at 37 C. and examined eigh- 

 teen 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, dextrose 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. 2 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: Endo 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 containing 1 c.c. of 0.1 per 

 cent, dextrose broth which have been kept at incubator temperature. 



1 For preparation and use of the Endo medium, see page 201. 



2 Kendall and Day, Jour. Med. Research, 1911, xx, 95. 



