6. How does the perspiration cool the body?
7. What change occurs in the circulation in the skin when the body is becoming too cold? When becoming too warm? What is the purpose of these changes?
[pg 278]8. How does alcohol cause one to feel warm when he may be losing too much of his heat?
9. What precaution should be observed by one in poor health, in taking a bath?
10. How may the cold bath be a means of improving the general health?
PRACTICAL WORK
Observations on the Skin and its Appendages.—Examine the palm of the hand with a lens. Note the small ridges which correspond to the rows of papillæ beneath the cuticle. In these find small pits, which are the openings of the sweat glands.
2. Examine the epidermis on the back of the hand and palm. At which place is it thickest and most resisting? Is it of uniform thickness over the palm? Try picking it with a pin at the thickest place, noting if pain is felt. Inference?
3. Examine a finger nail. Is the free edge or the root the thickest? Trim closely the thumb nail and the nail of the middle finger of one hand and try to pick up a pin, or other minute object, from a smooth, hard surface. The result indicates what use of the nails? Suggest other uses.
4. Examine with a microscope under a low power hairs from a variety of animals, as the horse, dog, cat, etc., noting peculiarities of form and surface.