ON MILK AND ITS ADULTERATION. 
183 
than those in the amount of butter. A very good judgment 
of the quality of milk may therefore be formed from the 
amount of butter which it yields on churning, or from the 
amount of cream which it throws up on standing. Instru- 
ments, adapted for measuring the quality of cream thrown up 
by different samples of milk, are called creamometers. These 
instruments are simply graduated glass-tubes, divided into 
100 equal degrees, in which milk is poured up to the division 
marked 0, and is kept at rest for twelve hours. Although the 
cream ometer does not furnish results which correctly repre- 
sent the real amount of butter in different samples, it never- 
theless affords a ready means of ascertaining whether milk is 
rich or unusually poor in butter, in other words, whether or 
not milk has been skimmed to a considerable extent. Good 
milk, of average quality, contains from 10^ to 11 per cent, of 
dry matter, and about 2| per cent, of pure fat. It yields from 
9 to 10 per cent, of cream. Naturally poor milk contains 
90 or more per cent, of water and less than 2 per cent, of pure 
fat, and yields only 6 to 8 per cent, of cream, or even less. 
Experiments on a large scale have shown me that the 
thickest cream does by no means give most butter, and that 
the cream which rises from different kinds of milk often varies 
greatly in composition. The indications of the creamometer, 
therefore, are fallible when samples of milk, produced under 
very different circumstances, have to be tested. Milk sent 
by rail is necessarily subject to a good deal of agitation, and 
throws up less cream than that which has been less disturbed. 
A direct experiment shows this very distinctly : — 
One hundred measures of new country milk, after standing 
for twenty-four hours at 62° F., gave me 12 percent, of cream 
by measure, whilst at the same time, a like quantity of the 
same, after having been gently shaken in a bottle, threw up 
only 8 per cent, of cream. We learn from this experiment 
that the shaking to which milk is subject when sent by railway 
has the effect of breaking some of the cream globules ; in 
consequence of which, either the fatty matters remain sus- 
pended in the milk, or more probably the cream thrown up 
gets richer in fat. Mr. Morton informs us that dealers in 
milk will give from 4d. to 6d. per barn gallon more for town- 
shed milk than for what is delivered by the railways. London 
milk in London, in other words, is worth more by a Jd. to 
|d. a quart than country milk in London. Mr. Morton founds 
on this fact an argument for the opinion which he entertains 
that country milk is generally inferior to London milk. 
Although it cannot be denied that the milk delivered by the 
metropolitan railways occasionally does not arrive in the best 
condition, probably the true reason why milk dealers pay a 
