REPORT NO. -2 OX THE ORIGIN AND PREVALENCE OF TYPHOID 
FEVER IN THE DISTRICT OE COLUMBIA. 
( 1907 .) 
Onr study of the prev’alence of typhoid fever in the District of 
Columbia was resumed in May. 1907, and all cases reported to the 
health office from IMay 1 to Xov’ember 1 have been investigated. Six 
hundred and seventy-fiv’e cases were reported in this period. In 
regard to nve of these cases no accurate information could be obtained, 
so they were abandoned, leavdng G70 cases for consideration in this 
report. 
DIAGNOSIS. 
It was not practicable for us to study the cases in clinical detail, 
but judging by the histories obtained in some instances, we are of 
the opinion that quite a number of the cases were incorrectly diag- 
nosed and should not hav’e been placed on the records as cases of 
typhoid fever. However, as the percentage of error in diagnosis was 
probably no greater this year than in prevdous years, and in order 
that our figures for this year should be comparable to those for 
previous years, we have included in our epidemiological studies ev^ery 
case reported as typhoid fever by the attending physician. 
With a view to forming some idea of the amount of error in ■ 
diagnosis, we examined the blood of 27 cases reported as typhoid 
fever between ^larch I and December 2. 1907. Five cubic centimeters 
of blood were withdrawn from an arm vein and planted at once into 
10 c. c. of sterilized ox bile. This was incubated for 21 hours, and 
subcultures made upon Endo and other media. This part of the work 
was done for us by Passed Assistant Surgeon A. M. Stimson. in the 
Division of Pathology and Bacteriology of the Hygienic Laboratory. 
The following is a summarv’ of the results : 
Number of specimens examined 27 
Specimens in which B. typliosns was found S 
Specimens in which B. parati/ijliosus A was found 1 
Total 9 = 33. 3 per cent. 
( 11 ) 
