The Skin : Part 4

Physiology and Hygiene for Secondary Schools
by Francis M. Walters

(Page 19 of 26)

Care of the Nails. - Relief from a blood blister under the nail is secured by boring a small hole through the nail with the sharp point of a sterilized penknife. This simple bit of surgery not only relieves the pain, but is frequently the only means of saving the nail. Ingrown toe nails are relieved by scraping a broad strip in the middle of the nail until very thin. This relieves the pressure, preventing the sides of the nail from being forced into the toe. While the finger nails should be trimmed in a curve, corresponding to the end of the finger, it is recommended that the toe nails be cut straight across as this method diminishes the pressure from the shoe and keeps the nails from ingrown. Shoes that pinch the toes should, of course, not be worn.

Care of the Hair. - Occasional washing of the hair is beneficial, but too much wetting causes decay of the hair roots, which leads to its falling out. The worst enemy of the hair is dandruff. A method of removing dandruff which is highly recommended is that of rubbing olive oil into the scalp and later of removing this with a cleansing shampoo. The olive oil is placed on the scalp with a medicine dropper and thoroughly rubbed in with the fingers. After three or four hours the hair is washed with soap and water (any good toilet soap will do) and rinsed with pure water. The hair is then dried, the surplus water being removed with a coarse towel.

Where the dandruff is very troublesome, this treatment may be given once or twice a week; but in mild cases once a month is sufficient. Massage of the scalp, by increasing the circulation at the hair roots, is beneficial, but irritation by a fine-tooth comb, a stiff hair brush, or by other means should be avoided. Frequent brushing and combing, however, are necessary both for the good appearance of the hair and for spreading the oil secreted by the glands at the hair roots.

Summary. - The skin forms the external covering of the body and also serves additional purposes. It is a most important agency in adapting the body to its physical surroundings, as shown by the part which it plays in the regulation of the body temperature. The skin should be kept clean and active, and skin wounds, even though small, should be guarded against infection.

Exercises. - 1. Name an example of each of the protective coverings of the body.

2. Compare the dermis and the epidermis with reference to thickness, composition, and function.

3. To what is the color of the skin due? How is the color of the skin affected by the sunlight?

4. What modifications of the epidermis are found on our bodies? What are found on the body of a chicken?

5. What different kinds of protection are provided by the skin?

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?

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 papilla 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.

To illustrate Cooling Effects of Evaporation. - 1. Wet the back of the hand and move it through the air to hasten evaporation. Observe that, as the hand dries, a sensation of cold is felt. Repeat the experiment, using ether, alcohol, or gasoline instead of the water, noting the differences in results. These liquids evaporate faster than water.

2. Wet the bulb of a thermometer with alcohol or water. Move it through the air to hasten evaporation. Note and account for the fall of the mercury.

D.C. Heath and Co. - Publishers
Original copyright 1909