48 UNIVERSITY OF WISCONSIN STUDIES 
969.59 calories or an increase of approximately 105 calories 
with each increase of 1 per cent fat. The use of the calo- 
rimeter, however, is too technical even for inspection work, 
From the above data it is evident that the use by the house- 
keeper of the fat content as an index of food value is correct 
in principle though the method of estimation is necessarily 
crude. The Babcock test for fat determination is both simple 
and accurate with the added advantage that the test itself 
is well understood and the necessary apparatus is ordinarily 
at hand. Accordingly, the fat content is in all particulars 
well adapted to serve as an index of food value of milk as it 
is delivered to the consumer. 
The safety of the milk as delivered may be about equally 
well guaranteed in either of two ways; by frequent inspection 
of the health of the cows and people concerned in its pro- 
duction and handling, or by proper pasteurization and pro- 
tection from reinfection. Safeguarding the milk by means 
of health inspection of cattle and men adds from 3 to 5 cents 
per quart to the cost of the milk while the expense of pasteur- 
ization varies from about 1 cent per quart in small quantities 
to about 1, cent per quart in laree quantities. Under such 
conditions it is not strange that practically all the actual 
advance in safeguarding municipal milk supplies has been 
made through the adoption of pasteurization. Where pasteur- 
ization is relied upon to make milk safe from germs of in- 
fectious diseases, there should be a requirement of tempera- 
ture recording devices in connection with the process and a 
freyuent inspection to ascertain that the apparatus is in 
proper working condition and that the milk is properly pro- 
tected after pasteurization. 
The housewife is aware that when a bottle of milk is un- 
disturbed for some time the dirt in the milk settles to the 
bottom and she accordingly looks at the bottom of the bottle 
to determine the cleanliness of the milk, In inspection work 
the amount of insoluble dirt in milk as delivered to the con- 
sumer may be estimated very aceurately by means of the 
sediment. test. ‘ 
