294 
TYPHOID PEVEK IX DISTEICT OE COLUMBIA. 
From an examination of the table p. 163 it will be seen that the fol- 
lo'wing waters show some chemical evidences of pollution: 
Laboratory- 
No. 
371. Red Oak Spring water. 
394. Magnesia Crystal table water. 
409. Xorwood artesian water (unfiltered). 
437. Hume Spring water. 
438. Crystal Rock table water. 
470. M. L. Harper’s distilled water. 
472. Renal Spring water. 
Of these waters six, viz, Nos. 394, 409, 437, 438, 470, and 472, 
contain considerably larger cpiantities of nitrites than we would 
expect a pure, wholesome water to contain, and No. 371 shows too 
large an amount of albuminoid ammonia. Of the table waters 
showing chemical evidences of pollution, the following were found on 
bacteriological examination to contain but few bacteria per cubic cen- 
timeter, viz. Nos. 371, 437, and 438, so that it is difficult to account 
for the large amounts of nitrites present. On the other hand the 
follo\\dng waters were found to contain large numbers of organisms 
per cubic centimeter, thereby confirming the results of the chemical • 
anal 3 ^ses, viz. Nos. 394, 409, 470, and 472. 
All things considered, however, it is not likely that the table waters 
of the District of Columbia are responsible for am^ of the typhoid 
fever occurring in this localit}^. 
ICE. 
At intervals during the months of August, September, and October 
chemical and bacteriological examinations were made of the different 
kinds of ice manufactured and sold in the District of Columbia. The 
results of these examinations are given in a table, page 106 of this 
report, and on page 110 are also given the results of Doctor Ljmch’s 
anah^ses of a number of samples of ice sold in the District. It 
will be seen from an examination of the table p. 106 that but few of the 
specimens of ice examined showed any chemical evidence of pol- 
lution, and according to statements appended to Doctor Ljmch’s 
reports none of the samples of ice examined b}^ him showed the pres- 
ence of anj" injurious contamination. As a rule the specimens of ice 
examined in the Hygienic Laboratory were found to contain but small 
amounts of total solids, and in some instances at least less chlorine 
than the water from which the manufactured ice was made. This 
probably results from the purification due to freezing. A number of 
the specimens of manufactured ice were found to contain relative^ 
large amounts of free ammonia. This frequently happens, however, 
inasmuch as it has been found to be exceeding!}^ difficult to prevent a 
slight leakage from the ammonia pipes into the atmosphere of the 
