On 
— 
MitK SuPPLY 
should be kept in glass bottles, tightly corked. The bottle con- 
taining the stock solution should be glass-stoppered. 
The Boiling Test.—Inspection by Ileating. The heating to 
the boiling point of samples of suspicious nulk furnishes a most 
reliable means to determine the fitness of such milk for condens- 
ing. In many instances milk may satisfactorily pass the other 
tests and yet it may not be in condition to stand the heat to 
which it will be subjected in the process. If it curdles, when 
boiled, it is obviously unfit for use. This test shows more than 
the acid test above. By its use the operator is able to detect 
milk otherwise abnormal, such as milk containing colostrum, etc., 
or the proteids of which are unstable for other reasons. 
Making the Test.—The boiling test is simple and can be 
manipulated rapidly. A sample of the questionable milk is taken 
into a small dipper. The dipper is held up against a steam jet 
turned down into the milk. Direct steam is turned into the 
milk until it comes to a boil. Jf flakes or specks of curd cling 
to the sides of the dipper, the milk is unfit for use. 
An alcohol lamp or gas burner on the platform may be used 
for heating the sample. In this case a few cubic centimeters 
of the milk are discharged with an ordinary pipette into an ordr- 
nary test tube, such as are in common use in the chemical labo- 
ratory and can be obtained from the drug store. The tube is 
held over the flame and the milk comes to a boil in less than 
a minute. If the milk is in good condition the sides of the glass 
tube remain perfectly clear. If it curdles upon heating, the sides 
of the tube show fine specks of the curd. The appearance of 
these specks condemns the milk. 
In the case of milk intended for evaporated milk, the boiling 
test is not sufficiently severe to reveal the fitness of the milk 
for the sterilizing process. For the reliable detection of unde- 
sirable milk for this purpose, the use of the pilot sterilizer or test 
sterilizer is recommended. Suspicious samples of milk are filled 
into tins, the tins are sealed and placed into the pilot sterilizer 
where they are given the same process of sterilization as is 
used for the finished product. Milk that withstands this sterili- 
zation can be depended upon to also pass safely through the 
process of manufacture. Milk that curdles in this test steriliza- 
