Illustrate the ordinary meaning of the term "absorption" by bringing the end of a piece of crayon in contact with water, or a piece of blotting paper in contact with ink, noting the passage of the liquid into the crayon or the paper. Show how absorption from the food canal differs from this kind of absorption.
Show by a diagram similar to Fig. 77 the two routes by which the foods pass from the alimentary canal into the blood stream.
CHAPTER XII - ENERGY SUPPLY OF THE BODY
If one stops taking food, it becomes difficult after a time for him to move about and to keep warm. These results show that food has some relation to the energy of the body, for motion and heat are forms of energy. The relation of oxygen to the supply of energy has already been discussed (Chapter VIII). We are now to inquire more fully into the energy supply of the body, and to consider those conditions which make necessary the introduction of both food and oxygen for this purpose.
Kinds of Bodily Energy.—The healthy body has at any time a considerable amount of potential, or reserve, energy,—energy which it is not using at the time, but which it is able to use as its needs require. When put to use, this energy is converted into such forms of kinetic energy[69] as are indicated by the different kinds of bodily power. These are as follows:
1. Power of Motion.—The body can move itself from place to place and it can give motion to things about it.
[pg 187]2. Heat Power.—The body keeps itself warm and is able to communicate warmth to its surroundings.
3. Nervous Power.—Through the nervous system the body exercises the power of control over its different parts.