on of the mineral matter as it exists in the milk. The best
known is that of Soldner, and the following is his calculation:

Per cent.
Sodium chloride 10.62
Potassium chloride 9.16
Monopotassium phosphate 12.77
Dipotassium phosphates 9.22
Potassium citrate 5.47
Dimagnesium citrate 3.71
Magnesium citrate 4.05
Dicalcium phosphate 7.42
Tricalcium phosphates 8.90
Calcium citrate 23.55
Calcium oxide, in combination with casein 5.13
------
100.00
------

The presence of citrates will be noted in this analysis. Citric acid,
which gives to lemons their acidity, and is also found in other fruits,
has been proved to exist in milk to the extent of about 0.2 per cent.
When alkaline or earthy citrates are burnt or oxidised in the blood, the
citric acid is destroyed, and corresponding carbonates remain. No doubt
the function of citrates in milk is to furnish to the body the earthy
and alkaline carbonates which are required in certain of its parts.

The mineral constituents of milk have many important functions to
perform in the building up and nutrition of the bodily organism.
Phosphate of lime is the principal constituent of the skeleton, and the
blood must be richly supplied with the alkalies, earths, and acids which
are comprehended in the ash.

Milk contains traces of many other substances, the most important of
which are several enzymes which assist in its digestion.

_General Properties of Milk._--The appearance of milk is known to every
one; it ought to be a pure white opaque liquid, but very generally it is
tinted a cream colour with anatto to give it an added appearance of
richness. The average specific gravity is about 1.031; or, to put it
another way, while a gallon of pure water weighs exactly 10 lbs., a
gallon of milk weighs 10 lbs. 5 oz. It freezes at 31 deg. F. and boils at
about one third of a degree higher than water.

When milk is examined under the microscope, the fat is found to be
distributed through it in a multitude of minute globules varying