393 
smaller quantities of formaldehyde than is ever employed in prac- 
tice. During the month of September, during which time special 
attention was paid to the subject of preservatives in the milk, 20 
cubic centimeters of each sample of the milk was distilled and a few 
cubic centimeters of the distillate collected in a small amount of dis- 
tilled water. The distillate was then tested for formaldehyde by a 
modification of the Hehner test (see Acree (14)), which in our 
hands enabled us to detect with certainty 1 part of formaldehyde 
in 1,000,000 parts of milk when a few drops of normal milk are used 
to supply the- proteid required in this test. 
In Table I are given the results of our analyses. 
In Table II, column (1), are given the serial numbers of the samples 
of the milks of the several dairies. These are the inspectors’ num- 
bers furnished by the health office of the District of Columbia. In 
column (2) are given the total number of samples analyzed from each 
dairy. In column (3), the inspectors’ numbers of such samples as 
were found to be below the standard of purity now fixed for the 
District of Columbia. In column (4), the total number of samples 
found to be below this standard. In column (5) are given the 
inspectors’ numbers of the samples which were found to contain 
measurable amounts of dirt, viz, quantities equal to or greater than 
0.07 per cent by volume of the milk. In column (6) are given the 
total number of milks from each dairy containing measurable 
amounts of dirt. 
It will be seen from the totals given at the end of Table II that out 
of a total of 452 samples of milk analyzed 55 were found to be below 
standard, and of these which were found to be below standard 48 
contained less than 3.5 per cent of fat and 17 gave evidence of having 
been watered. In addition to the 55 samples found to be below 
standard, 4 samples gave results indicating the probability of their 
having been watered, and 2 of the samples had probably been skimmed. 
It will also be seen from Table II that out of 452 samples analyzed 242 
contained measurable amounts of dirt, varying from 0.07 per cent by 
volume of the milk to ten times this amount, viz, 0.7 per cent by vol- 
ume. Only one of the samples out of the 452 analyzed was found to 
contain preservatives. This particular sample contained small 
amounts of boric acid. None of the samples contained artificial 
coloring matters. The following additional facts concerning certain 
of these samples are not without interest in this connection : Samples 
148B, 235B, 240B, 241B, 280B, 297B, 1C, 2C, 8C, 44C, 58C, and 60C 
were put up in bottles containing stale milk. Samples 48 A, 196B, 
203B, 216B, and 237B were put up in dirty bottles. Feces were 
found in sample HOB, grass in sample 121B, pieces of straw in sam- 
