the numerous diseases that have been known to be carried to whole
families and communities through the milk supply.

37. Although pasteurizing is done on a large scale in dairies, there is
no reason why the housewife cannot pasteurize the milk she buys,
provided it is raw milk and she feels that it is not safe to use. If
pasteurizing is to be done frequently and large quantities of milk are
to be treated, it would be advisable to purchase the convenient
apparatus that is to be had. However, if only a small quantity of milk
is to be pasteurized at a time, a simple improvised outfit will prove
satisfactory, because milk pasteurized in the home may be heated in the
bottles in which it is received. Such an outfit consists of a dairy
thermometer, a deep vessel, and a perforated pie tin or a wire rack of
suitable size.

38. To pasteurize milk in the home, proceed in the manner illustrated
in Fig. 3. Place the rack or invert the perforated pie tin in the bottom
of the vessel, and on it place the bottles of milk from which the caps
have not been removed. Make a hole through the cap of one bottle, and
insert the thermometer into the milk through this hole. Then fill the
vessel with cold water to within an inch or so of the top of the
bottles, taking care not to put in so much water as to make the bottles
float. Place the vessel over the fire, heat it until the thermometer in
the bottle registers a few degrees over 150 degrees Fahrenheit, and keep
the milk at this temperature for 15 to 20 minutes. At the end of this
time, the milk will be sufficiently pasteurized and may be removed from
the fire. As soon as it is taken from the water, cool it as rapidly as
possible by running cold water into the vessel slowly or by placing the
bottles in several changes of water, taking care not to place the hot
bottles in very cold water at first, as this may cause them to crack.