aceous food.

Notice the greenish-yellow colour. Recall this same colour in water in
which potatoes, cabbage, or other vegetables have been cooked. Tell the
pupils that this colour is given by _mineral matter_ being dissolved in
the water.

There is still the curd of milk to examine. The use of the senses does
not allow us to definitely decide what food substance the curd is. Tell
the pupils it is protein, or find the name by a process of reasoning,
thus: Recall the fact that babies live for several months on milk alone
and during that time build all tissues of the body. Milk, therefore,
must contain all tissue-building substances. Review the food substances
which are necessary to build all body tissues--mineral matter, protein,
and water. We have found the mineral matter and water in milk, but not
the protein. Since curd is the only remaining part of milk, it must be
largely protein.

Tell the pupils that the scum which comes on the top of milk, when it is
boiled, is another kind of protein of which there is a small amount in
solution in milk.

Lead the pupils to see that if starch were present, it would be in a raw
form, and in this form is indigestible.

LESSON II

FOOD VALUE

The analysis of milk gives a key to the food value of milk and each of
its by-products (cream, butter, butter-milk, sour milk, skim milk, curd,
whey, cheese, junket). These may now be briefly discussed as to
composition, food value, and cost.

CARE

Milk readily absorbs odours, bacteria, etc., and should be kept in
covered, sterilized dishes in a pure, cool atmosphere.

EFFECT OF HEAT

Experiments should be made to show the effect of simmering and boiling
temperatures. To save time, a different experiment may be given to each
pupil, and the results reported.

1. Simmer sweet milk and note the flavour.

2. Boil sweet milk and note the flavour.

3. Simmer the curd of milk. Examine its texture.

4. Boil the curd of milk. Examine its texture and compare it with the
simmered curd.

5. Boil skim milk and note the scum.

6. Simmer skim milk and note the absence of scum.

NOTE.--From the above experiments deduce the
effect of heat on protein.

Practice lessons may now be given in preparing simple dishes in which
milk is the main ingredient, or, at least, recipes may be given for
these to be made at home. The following would be suitable: cream sauce,
cream soups, custard, junket, cottage cheese, albuminiz