The simplest test for albumen is the fact that it is con-
gested by heat ; this is the test for albumen used by phy-
sicians in diagnosing diseases of the kidneys.
Add to a test-tube one-third full of the suspected fluid
two or three drops of strong nitric acid. Heat gently — a
pale yellow color will result. Allow the liquid to cool.
Add a few drops of ammonia. A deep yellow color indicates
the presence of ammonia ; a deep orange color indicates the
presence of albumen.
Method. — The relation of the white of an egg to the yolk,
its color and its consistency, are too well known and too obvi-
ous to be made the subject of much study. Instead, ask the
question: Is the white of the egg perfectly sokible in cold
water? Let the children experiment. What is the effect
of heat upon it ? Let them boil water in which the albumen
has been dissolved, first filtering it.
Teach them the name of this class of foodstuffs, and their
great value in repairing the body. They and their kind are
the only flesh builders ; other foods are fuel foods. Eemind
them of the previous experiment with curds, and tell them
that the great value of meats and fish lies in the fact that
they, too, are rich in proteids.
These are all of animal origin. Do any foods of vegetable
origin contain proteids ? Why do you think so ? (Herbiv-
orous animals must get their flesh builders from the vege-
table kingdom.)
Let each child chew a handful of clean wheat, breaking
the grains carefully in the mouth, and chewing with the idea
of making wheat gum. The action of the saliva removes
therefore, it is approximately correct to speak of the protein or proteids,
or nitrogenous foods, as the flesh formers. It is much hetter to teach this
tlioroughly than that the children should have in their minds a painfully
distorted picture of the truth, in which, owing to the difficulty of teaching
them, the amids, extractives, and gelatinoids are very much in the fore-
ground.
FOODS 105
from the wheat its starch, sugar, and some of the oils.
Practically only the tenacious gluten is left. This is almost
pure protein. Iodine may be used to prove the original
presence of the starch and its disappearance, resulting from
the process of chewing.
The presence of gluten in flour may be demonstrated by
letting each child wash thoroughly a small quantity of it
loosely tied in a cheese-clotli bag. The starch and sugar is
washed away. The gummy mass left behind is almost pure
protein.
For the clearer understanding of gelatinoids it might be
well first to use two familiar experiments to demonstrate the
dual composition of bones.
First, burn a good-sized bone in a hot fire, protecting it
from the charring contact with the flame, if possible. All
the animal matter will be burned out, leaving behind only a
white, porous, limy framework. Children will do this
work at home under direction, and love to own and exhibit
the resulting specimens.
Second, cover a fair-sized clean bone with dilute hydro-
chloric acid over night. In the morning the salts of lime
will be dissolved. The animal matter which remains is of
the nature of gristle. The bone may be twisted and bent, or
even tied in a knot, with ease.
This animal matter is a gelatinoid.
Page 53
Presented as published in 1900. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
The simplest test for albumen is the fact that it is coagulated by heat ; this is the test for albumen used by physicians in diagnosing diseases of the kidneys.
Add to a test-tube one-third full of the suspected fluid two or three drops of strong nitric acid. Heat gently — a pale yellow color will result. Allow the liquid to cool. Add a few drops of ammonia. A deep yellow color indicates the presence of ammonia ; a deep orange color indicates the presence of albumen.
Method. — The relation of the white of an egg to the yolk, its color and its consistency, are too well known and too obvious to be made the subject of much study. Instead, ask the question: Is the white of the egg perfectly soluble in cold water? Let the children experiment. What is the effect of heat upon it ? Let them boil water in which the albumen has been dissolved, first filtering it.
Teach them the name of this class of foodstuffs, and their great value in repairing the body. They and their kind are the only flesh builders ; other foods are fuel foods. Remind them of the previous experiment with curds, and tell them that the great value of meats and fish lies in the fact that they, too, are rich in proteids.
These are all of animal origin. Do any foods of vegetable origin contain proteids ? Why do you think so ? (Herbivorous animals must get their flesh builders from the vegetable kingdom.)
Let each child chew a handful of clean wheat, breaking the grains carefully in the mouth, and chewing with the idea of making wheat gum. The action of the saliva removes
therefore, it is approximately correct to speak of the protein or proteids, or nitrogenous foods, as the flesh formers. It is much better to teach this thoroughly than that the children should have in their minds a painfully distorted picture of the truth, in which, owing to the difficulty of teaching them, the amids, extractives, and gelatinoids are very much in the foreground.
from the wheat its starch, sugar, and some of the oils. Practically only the tenacious gluten is left. This is almost pure protein. Iodine may be used to prove the original presence of the starch and its disappearance, resulting from the process of chewing.
The presence of gluten in flour may be demonstrated by letting each child wash thoroughly a small quantity of it loosely tied in a cheese-clotli bag. The starch and sugar is washed away. The gummy mass left behind is almost pure protein.
For the clearer understanding of gelatinoids it might be well first to use two familiar experiments to demonstrate the dual composition of bones.
First, burn a good-sized bone in a hot fire, protecting it from the charring contact with the flame, if possible. All the animal matter will be burned out, leaving behind only a white, porous, limy framework. Children will do this work at home under direction, and love to own and exhibit the resulting specimens.
Second, cover a fair-sized clean bone with dilute hydrochloric acid over night. In the morning the salts of lime will be dissolved. The animal matter which remains is of the nature of gristle. The bone may be twisted and bent, or even tied in a knot, with ease.
This animal matter is a gelatinoid.