TYPHOID FEVEK IH DISTEICT OF COLUMBIA. 
25 
nated from all large cities having an abundant water supply and 
sewerage system. We unhesitatingly subscribe to this view and be- 
lieve that the shallow wells in the District of Columbia should be con- 
demned — a conviction that is abundantly confirmed by the results 
of our chemical and bacteriological examinations. 
From the fact that 31 of the 63 shallow wells show indications of 
sewage pollution and 29 are suspicious we feel justified in recommend- 
ing the permanent closing of all the shallow wells in the District of 
Columbia, and if for any reason any of those now regarded as sus- 
picious should be continued in use, laboratory facilities should be 
afforded the health officer of the District to watch them closely and 
authority granted him to close immediately any such well upon the 
first indication of sewage pollution, or, as an alternative, close the 
shallow wells and sink deep wells in their place. 
THE TABLE WATERS. 
There is on sale in the city of Washington a great variety of ^‘min- 
eraF’ waters, both foreign and domestic. One dealer publishes a list 
of more than sixty kinds. The inspection was confined to those 
table waters collected from sources in or near the city or bottled 
here. Studies were made of the source and mode of purveyance of 
these waters and samples were taken for chemical and bacteriological 
examination with a view of discovering any injurious contamination. 
Several instances of fraudulent labeling were discovered. 
The claims of some dealers as to the sterilization of their water 
bottles could not be substantiated. 
No relation between the use of bottled waters and the spread of 
typhoid fever is apparent in the District of Columbia. 
THE POTOMAC DRAINAGE BASIN. 
The Potomac River at Great Falls drains an area of about 11,400 
square miles. The population of this area was estimated to be, in 
1900, about 500,000, or 44 per square mile. The velocity of 
flow of the Potomac is extremely variable. It has been estimated 
that it takes from four to seven days for the water to travel from 
Cumberland to Great Falls, a distance of about 176 miles. Typhoid 
fever prevails to a greater or less degree in every part of the drainage 
basin. No data for an accurate determination of its degree or sea- 
sonal prevalence are obtainable ; such data as were obtained indicate 
that its seasonal prevalence closely corresponds to that of Washington. 
The waters of the Potomac are directly polluted by sewage at 
numerous points. TR’s direct pollution is contributed by not more 
than 45,000, or 9 per cent of the total population of the watershed. 
Of this pollution about 80 per cent enters the river at points 176 
miles or more from the intake of the Washington Aqueduct at Great 
