4 
292 TYPHOID FEVER IX DISTRICT OF COLUMBIA. 
In the following table are given the total number of shallow wells 
in use in the several sections of the city, together with the total num- 
ber in each section regarded as unfit for drinking purposes: 
Section of the city , 
Total number 
of shallow 
weUs in use. 
Total number 
condemned as 
unfit for use. 
Northeast 
13 
6 
Northwest 
29 
13 
Southeast 
26 
11 
Southwest 
1 
1 
Total 
63 
1 
31 
It vdll be observed that, leaving out of consideration the southwest 
section of the city, in which but one shallow well is in use, and that a 
highly polluted one, the number of wells regarded as unfit for use in 
various portions of the city bears to the whole number of wells now 
in use in the several sections of the city about the same ratio, viz, 
about one-half. In other words, it is evident from our studies that 
the polluted wells are not confined to any particular section of the 
city, but are about equally distributed over the entire community. 
Viewed in all of its aspects, the situation with regard to the 
shallow wells in the District does not seem to be greatly improved, 
except as to the fewer number of wells in actual use over what it was 
fifteen years ago. In 1889, 310 wells were in use in the District, 75 
per cent of which, according to the report of the engineer of the Dis- 
trict for 1889 and 1890, were polluted. According to Edchardson, 
270 were in use in 1891, and from his analyses he was led to regard 
only 27 per cent of them as passable.”® According to our findings, 
of the 63 in use to-day 50 per cent are polluted, and of the remaining 
50 per cent nearly all show chemical evidences of remote pollution, 
so that the shallow wells in use throughout the District to-day show 
but slight improvement in the quality of the water supplied over 
those in use in 1889. The slight improvements observed can be 
readily accounted for by the decrease in the number of privies now in 
use in the city and by the extension and improvement in the sewerage 
system. 
While none of the cases of typhoid fever occurring during the period 
covered by this investigation were traceable directly to the use of ! 
the water of any of the shallow wells, the shallow wells of the Dis- i 
trict of Columbia must be looked upon as latent sources of danger to 
the health of the community, and serve to greatly increase the labor j 
incident to the proper sanitary control of the water supply of the 
District. So far as their effect on the problems of sanitation is con- 
cerned each well must be looked upon as an independent water sup- ; 
o Jour, of Anal, and Appl. Chem., Vol. V., pp. 1-36. 
