18 BULLETIN 1, U. S. DEPARTMENT OF AGRICULTURE. 
the very smallest fill the bottles from a large clipper or pitcher. In 
the last few years capping machines have been perfected so that the 
bottles may be filled and capped without being touched by human 
hands. This is a decided advantage, as the old method of placing 
the caps in the bottles by hand was liable to result in serious con- 
tamination. Practically all of the certified establishments sterilize 
the caps which are used in the milk bottles. This sterilization is best 
accomplished by dry heat, as steam is apt to swell the paper caps so 
that they do not fit the capping machine or the neck of the bottle. 
The caps are placed in a small cylinder or rolled in brown paper and 
placed in dry ovens, where they are heated for about an hour. 
Practically all certifiecl-milk dairies now use some sort of an out- 
side cover to protect the mouth of the bottle from being infected 
with dust or dirty water. A variety of appliances for this purpose 
are in use, some of which are shown in Plate V. 
TRANSPORTATION AND DELIVERY. 
Great care is taken to see that certified milk is always kept cold. 
It is cooled in the dairies by ice water, brine, or direct expansion 
almost clown to the freezing point, and from that time until it is 
delivered to the consumer it is kept well packed in ice to prevent the 
multiplication of bacteria. 
The distribution of certified milk is clone in some cases by the pro- 
ducer, but very often the producer ships to some retailer in the city, 
who handles the product for him. 
Some certified dairies maintain laboratories in charge of physicians 
or trained nurses where certified milk is modified for infant feeding 
according to physicians' prescriptions. The modified milk is put up 
in nursing bottles, sufficient feedings for one day being prepared at a 
time and delivered to the consumer in a refrigerator case. 
INFORMATION SECURED FROM PRODUCERS. 
In order to secure accurate data relative to the production of cer- 
tified milk, a list of questions was sent to owners and operators of 
certifiecl-milk farms. Answers were received from a large number. 
It was found that quite a number had discontinued the production of 
certified milk for one reason or another, several having stopped 
because of the lack of sufficient markets for their product or because 
the production was attended with financial loss. Answers to the 
questions were received from 92 dairies, distributed among 17 States. 
NUMBER AND BREED OF COWS. 
The number of cows in herds producing certified milk varies from 
to 600. It was found that the average number of cows in certified 
dairies was 88. Practically every breed is represented in these herds. 
