Of course, there would be no acid in milk if there were no sugar in
it. The proportion of sugar is shown by the following analysis of an
average sample of good milk made by Dr. Voelcker, the late chemist of
the Royal Agricultural Society of Great Britain:
Water 87.30
Butter 3.75
Caseine 3.31
Milk-sugar and extractive matter 4.86
Mineral matter (ash) 0.78
------
Total 100.00
It will be seen by this that the per cent. of sugar is at least 4.50,
if we deduct the extractive matter, the proportion of which is not
given. Numerous German analyses show it to range from 3.50 to 5.75
per cent. Henry and Chevalier put the average at 4.77, and Prof. L.B.
Arnold says milk from cows in perfect health should contain, during the
month of August, 4.30 to 5.50 per cent. We will call it 4.50 per cent.
There is 87.30 per cent of water.