METHODS AND RESULTS OF THE EXAMINATION OF WATER 
SUPPLIES OF DAIRIES SUPPLYING THE DISTRICT 
OF COLUMBIA. 
By B. Meade Bolton, M. D,, 
Biochemic Division, Bureau of Animal Industry, Department of Agriculture. 
The present investigation was undertaken in cooperation with the 
Dairy Division, Bureau of Animal Industry, Department of Agri- 
; culture, and had for its purpose the determination of the general 
sanitary condition by personal observation of the source of the 
supply, whether spring, well, or cistern; the location, surroundings, 
i apparent liability of pollution due to proximity to the barnyard or 
domestic source of contamination or to careless and slovenly methods 
of drawing the water; furthermore in each case the purity of the 
water as indicated by the number of bacteria per 1 cubic centimeter 
, and the presence or absence of the colon bacillus was determined 
1 by bacteriological examination of specimens plated on the spot 
and by chemical examination of samples sent as promptly as feasible 
after drawing. The chemical examination was made under the 
direction of Dr, T. M. Price, of the local laboratory in Washington. 
; The counting of the plates to determine the number of bacteria and 
[ the culture tests for the detection of the colon bacillus were made by 
I Dr. F. W. Tilley, of the Biochemic Division. Doctor Tilley has also 
I assisted in the preparation of the accompanying tables. Dr. E. M. 
I Santee, formerly of the dairy division, made photographs in most 
I cases, and Mr. Clarence B. Lane, assistant chief of the Dairy Division, 
iin others of the water supplies at the farms visited. These have 
I all been included in a separate report to the chief of the Bureau of 
i Animal Industry. 
The investigation was started April 8, 1907, and was continued with 
} some necessary interruption until September 1 1 , 1907. It was made to 
include the dairies along the line of the Southern Railway from Vienna, 
j Va., to Bluemont, Va., and consequently embraced those dairies 
'which ship milk from Round Hill, Purcell ville, Hamilton, Sterling, 
r Herndon, Paeonian Springs, Clarkes Gap, Leesburg, Belmont Park, 
Ashburn, Wiehle, Hunter, Vienna, and also embraced most or all 
I of the dairies around Frederick and Walkersville in Maryland. A 
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