s particularly abundant in the highly nucleated
secreting cells of the glandular organs, such as the liver, pancreas,
and the thymus gland. The nucleoproteins are composed of simple
proteins and nuclein. Nucleic acid is rich in phosphorus and upon
decomposition yields some of the purin bases (xanthin, adenin,
guanin), a carbohydrate and phosphoric acid.[7]

(b) ~Phosphoproteins.~--Compounds in which the phosphorus is in
organic union with the protein molecule otherwise than a nucleic acid
or lecithin. Examples: caseinogin (milk), ovovitellin (egg yolk).

(c) ~Hemoglobin.~--Much of the greater part of the iron existing in
the body occurs as a constituent of the hemoglobin of the red blood
cells. When the intake of iron is not sufficient to cover the output,
there must be a consequent diminution in the hemoglobin of the blood
with a corresponding development of anemia.

The importance of knowing these characteristic proteins is apparent.
Not only will such knowledge lead to a more intelligent use of protein
foods in the normal dietary, but it will prove of the greatest
assistance in the adjusting of the foodstuffs in diet for individuals
suffering from certain abnormal conditions.

In abnormal conditions this knowledge of the various proteins--their
composition, source, and behavior in the body assumes a position of
the greatest importance; since it represents the means for
safeguarding a patient from the results caused by the wrong kind of
food. In certain types of nephritis, for example, it is perfectly safe
to give milk where the ingestion of meat and eggs might cause serious,
if not fatal, results. In treating gout, when it is deemed advisable
to limit the purin foods in order to control in a measure the
retention of uric acid in the body, the realization that certain of
the nucleoproteins, upon being broken down in the body, yield the
purins, which in turn give rise to the production of uric acid, will
permit the nurse to adjust the diet so as to eliminate such foods
entirely (see Gout). The importance of keeping the hemoglobin content
of the blood normal has already been mentioned.

~The Effect of Heat upon Proteins.~--The fact that certain proteins
are most susceptible to heat has already been stated, but the
application of this knowledge in the preparation of protein foods is
important. In milk, for example, whole raw milk forms a large hard
curd; whereas boiled milk curdles in a much finer and softer form.