t needs some substance to make
it hard and rigid--the mineral matter which was dissolved out.

NOTE.--This is an excellent time to show the
necessity for bone-building mineral in the diet
of babies and young children. If they do not
get this mineral substance during the growth
period, they cannot have hard, rigid bones, and
their bodies are apt to become misshapen--bow
legs, curved spines, etc. This substance is
also necessary for hard, sound teeth.

Draw attention to the fact that the mineral matter in milk and eggs is
in solution, and therefore ready to be used by the body. Mineral matter
is not in solution in bone, and cannot be dissolved by the digestive
process, therefore it is practically of no use as food.

Compare the connective tissue of bone with that of fat, and let the
pupils account for the difference in thickness. Lead them to see that
connective tissue can be dissolved in hot water, and in this way may be
extracted from the mineral part of bone. The housekeeper may do this
herself, or she may buy it already extracted, as gelatine.

5. Composition of muscle:

(1) Connective tissue

(2) Red part, made up of microscopic tubes
holding a red juice. The juice contains: (_a_)
Water (_b_) Red colour (_c_) Flavour (_d_)
Muscle albumen--a protein substance similar to
egg-white (_e_) Mineral matter.

[Illustration: Muscle fibres highly magnified

Bundle of fibres. Tubes of one fibre. Proper carving of fibres--across
the grain.]

It should be made clear that the walls of such tiny tubes can never be
thick enough to be tough. Attention should be called to the real cause
of toughness--the thick connective tissue.

NOTE.--Very small pieces of meat will serve for
specimens. Tough meat is better, because it
shows the connective tissue more plainly. When
the muscle is being examined, it should be
carefully scraped with a knife, until a layer
of connective tissue is laid bare. The red part
that is scraped off should be explained, and a
drawing should be made to illustrate it.

Minced lean beef should he soaked in a little cold water for at least
twenty minutes, to extract the muscle juice for examination. The juice
should be strained through a cheesecloth and poured into a glass. It
shows nothing but water and a red co