POTOMAC RIVER WATER SUPPLY RELATIVE TO TYPHOID FEVER. 269 
and Marine-Hospital Service, and reported by Dr. J. J. Kinyoun, 
then director of the Laboratory, in the Annual Report of the Super- 
vising Surgeon-General for 1898. Passed Assistant Surgeon E. K. 
Sprague conducted the bacteriological examinations, which consisted 
of semi- weekly analyses from a constantly flowing tap from July 1, 
1897, to February 28, 1898. The following table gives the quantita- 
tive results : 
Number of bacteria found in Potomac water at each examination. 
Date. 
Aerobic bacteria 
found in 1 cubic 
centimeter. 
Anaerobic bacte- 
ria in 1 cubic : 
centimeter. ! 
1897. 
July 1 
650 
Count not made. 
6 
400 
100 , 
9 
4,600 
2,800 : 
12 
366 
33 
15 
33 
66 
19 
266 
400 
22 
200 
66 
26 
166 
66 
29 
? 150 
? 100 ; 
31 
466 
116 
Aug. 2 
316 
100 
5 
183 
66 
9 
216 
116 
12 
133 
83 
16 
300 
33 
19 
100 
200 
23 
283 
433 
26 
250 
66 
30 
166 
300 
Sept. 2 
366 
133 ! 
6 
116 
116 
9 
2,200 
1,200 
13 
150 
200 
16 
50 
500 1 
23 
150 
16 
' 27 
150 
100 
30 
200 
0 
Oct. 4 
16 
50 : 
7 
33 
33 ! 
11 ....... 
116 
83 
14 
83 
50 
18 
216 
100 
21 
83 
50 
25 
33 
50 
28. 
167 
50 
Date. 
Aerobic bacteria 
found in 1 cubic 
centimeter. 
Anaerobic bacte- 
ria in 1 cubic 
centimeter. 
1897. 
Nov. 1 
17 
50 
4 
167 
33 
8 
733 
117 
11 
183 
133 
15. 
250 
83 
18 
317 
117 
22 
100 
83 
25 
466 
216 
28 
833 
1,000 
Dec. 2 
2,267 
1,200 
. 6 
4,300 
300 
9 
900 
600 
13 
700 
533 
16 
1,200 
366 
20 
933 
433 
23 
1,200 
300 
27 
367 
Count not made. 
30 
283 
Do. 
1898. 
Jan. 3 
No growth. 
67 
6 
.533 
100 
10 
567 
167 
13 
500 
200 
17 
566 
66 
20 
467 
233 
24 
700 
400 
27 
733 
167 
31 
433 
566 
Feb. 3 
400 
400 
7 
633 
66 
10 
167 
87 
14 
166 
200 
17 
333 
33 
21 
333 
66 
24 
1,133 
166 
28 
1,000 
533 
It will be seen from this table that the largest number of bacteria 
occur in Potomac River water during the winter and spring months. 
It is therefore evident that typhoid fever is most prevalent in Washing- 
ton while the number of bacteria in the river water is lowest, and vice 
