46 
Water. 
Number of 
cases. 
Public wells and springs: 
Solely 
Principally 
Occasionally : 
Bottled: 
Solely 
Principally 
Occasionally 
Private wells or springs in the District of Columbia: 
Solely 
Principally 
Occasionally 
Various sources out of the District of Columbia: 
Principally 
Occasionally 
1 
1 
12 
0 
4 
8 
9 
31 
6 
4 
121 
BACTERIOLOGICAX, EXAMINATION OF THE POTOMAC WATER 
SUPPLY. 
The examinations were made in the Division of Pathology and 
Bacteriology of the Hygienic Laboratory by Assistant Surgeon W. W. 
Miller, assisted b}^ Assistant Surgeon Lasher Hart and Dr. Walter D. 
Cannon. The samples of water examined were as follows : 
1. Kaw Potomac Kiver 'water taken from the inlet of Dalecarlia 
reservoir, or when Dalecarlia was by-passed, from the inlet at George- 
to'vwi reservoir (August 31 to Xovember 26, 1908). This represents 
the Potomac River w^ater as it is introduced into the first sedimenta- 
tion reservoir. 
2. Applied 'water taken from the Washington city reservoir from 
'which the \vater is run on to the filter beds. 
3. Filtered w^ater taken from the outlet of the storage reservoir 
for the filtered '^vater. This represents the mixed effluents from all 
the filter beds and the 'water just before it passes from the reservoir 
to the conduits for distribution to the city. 
4. The tap water in different sections of the city. This represents 
the filtered 'water after it has traversed the 'water mains and as distrib- 
uted in the three different pressure areas of the system, namely, 
(a) gravity, (b) first high, and (c) second high; the taps in Lafayette 
Square, Washington Circle, Franklin Square, and in southwest Wash- 
ington being in the gravity pressure area, the tap at the Hygienic 
Laboratory being in the first high, and the tap at 3211 Thirteenth 
street XW., being in the second high pressure area. 
