Under this heading I will consider fish and other sea-creatures.
[Sidenote: Nutrients in fish]
[Sidenote: Fish as brain food]
The flesh of most fish is quite free from fat, and consists almost
entirely of water and proteids. It is less concentrated than the flesh
of warm-blooded animals, averaging about 18 to 20 per cent proteids, and
60 to 70 per cent water. The percentage of ash in fish is also somewhat
greater than in any other flesh food. The popular idea that fish is good
food for the brain originated in the fact that analysis of some fish
shows a considerable percentage of phosphorus, which substance is also
found in the brain. There is no reason to believe, however, that the
liberal use of fish would develop or produce an excess of brain-tissue.
Any well-balanced diet contains ample phosphorus to nourish the brain.
The true science of human nutrition lies in the knowledge of selecting,
combining, and proportioning food according to age, climate, and work.
When this is done, the tendency of the body is to eliminate dis-ease and
to assume normal action; this accomplished, every part of the anatomy
shares in the general improvement.
[Sidenote: Fish superior to flesh of mammals]
My theory advanced against the use of meat because of nitrogenous
decomposition products, holds true with fish, though in a somewhat
limited degree. The decomposition products of cold-blooded animals are
not identical with those of mammals, hence their consumption as food
does not add to the percentage of human waste-products so directly as do
other meats.
[Sidenote: Oysters and clams unfit for food]
Oysters and clams, which are generally eaten uncooked, are recommended
by many authorities as valuable sources of proteid. The serious
objection to their use, and especially uncooked, is the fact that they
are grown in the sea-water around harbor entrances which are flooded
with sewage, and hence they are likely to be contaminated with typhoid,
or similar germs. The actual food value in shell-fish is quite small.
They contain only about ten per cent of proteids, and are scarcely worth
considering as a source of nutrition.