ure sugar, or olive-oil, (articles that contain no nitrogen,)
for several weeks, and the evil effects of non-nitrogenous nutriment
will be manifested. At first, the dog will take his food with avidity,
and seem to thrive upon it; soon this desire for food will diminish,
his body emaciate, his eye become ulcerated, and in a few weeks he
will die; but mix bran or sawdust with the sugar or oil, and the
health and vigor of the animal will be maintained for months. A
similar phenomenon will be manifested, if grain only be given to a
horse, without hay, straw, or material of like character. (Appendix
H.)

294. Some articles of food contain the elements of chyle in great
abundance, yet afford but little nutriment, because they are difficult
of digestion; while other articles contain but a small quantity of
these elements, and afford more nourishment, because they are more
easily affected by the digestive process.

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293. How has the effect of non-nitrogenous nutriment been illustrated?
294. Why do some articles of food that contain the elements of chyle
afford but little nutriment? Why do articles that contain a small
quantity of these elements afford more nourishment? 295. How was the
time required for digesting different articles of food ascertained?

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295. The following table exhibits the general results of experiments
made on Alexis St. Martin, by Dr. Beaumont, when he endeavored to
ascertain the time required for the digestion of different articles of
food.[10] The stomach of St. Martin was ruptured by the bursting of a
gun. When he recovered from the effects of the accident under the
surgical care of Dr. Beaumont, the stomach became adherent to the
side, with an external aperture. Nature had formed a kind of valve,
which closed the aperture from the interior, and thus prevented the
contents of the stomach from escaping; but on pushing it aside, the
process of digestion could be seen. Through this opening, the
appearance of the coats of the stomach and food, at different stages
of digestion, were examined.

[10] The time required for the digestion of the different articles of
food might vary in other persons; and would probably vary in
the same individual at different periods, as the employment,
health, season, &c., exert a modifying influence.

TABLE,

SHOWING THE MEAN TIME OF DIGESTION OF THE DIFFERENT
ARTICLES OF DIET.

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