Note.—Let the pupil review the anatomy and physiology of the skin from Fig. 117 or from anatomical outline plate No. 9.

657. The sensibility of the skin, and the activity of the oil and perspiratory glands, are modified by the condition of the cuticle, the temperature of the skin and body, the purity and warmth of the air, and the character of the light to which the body is exposed. Thus, to maintain a healthy action of every part of this membrane, attention should be given to Clothing, Bathing, Light, and Air.

658. Clothing, in itself, does not bestow heat, but is chiefly useful in preventing the escape of heat from the body, and in defending it from the temperature of the atmosphere. In selecting and applying clothing to our persons, the following suggestions should be observed.

659. The material for clothing should be a bad conductor of heat; that is, it should have little tendency to conduct or remove heat from the body. This depends mainly on the property possessed by the material in retaining atmospheric air in its meshes.

657–716. Give the hygiene of the skin. 657. What influences modify the action of the oil and perspiratory glands? To what must attention be given to maintain a healthy action of the skin? 658. What is said in regard to the clothing? 659. Mention a property that the material for clothing should possess. 660. What property in the selection of clothing should we avoid? Why?

661. Furs contain a greater amount of air in their meshes, than any other article, and they absorb no moisture; consequently, as an article of dress, they are best adapted to those who are exposed to great vicissitudes of heat and cold.

662. Woollen cloth retains more air in its meshes than any other article except furs and eider down, and it absorbs but very little moisture. These properties, together with its comparative cheapness, render it a good article of apparel for all classes of persons. The only objection to its general use is, the disturbance of the electricity of the system, and the irritation to delicate skins from the roughness of its fibres.

Observation. Flannels are not only beneficial, during the cold season, in preventing colds and rheumatism, but they are of great utility in the warm season, in shielding the system from the chills at evening, that induce disease of the alimentary canal. Their general use among children and delicate females, would be a preventive of the “season complaints” prevalent in the months of August and September.

663. Cotton contains less air in its meshes than woollen, but much more than linen. In texture, it is smoother than wool, and less liable to irritate the skin. This fabric absorbs moisture in a small degree. In all respects, it is well adapted for garments worn next the skin. When woollen flannels irritate the skin, they may be lined with cotton.

661. Give the properties of fur. As an article of dress, to whom are they best adapted? 662. Give the properties of woollen cloth. Is this a good article for clothing? What objection? What are the advantages of wearing flannels? 663. What are the qualities of cotton as an article of dress? 664. Of silk?

665. Linen is not only a good conductor of heat, and consequently a poor article of apparel, but it likewise absorbs the fluids carried from the system by the agency of the oil and perspiratory glands. When garments are made of this material, the body is not surrounded by a layer of air, but by one of moisture. This still further increases its power to conduct heat from the system, rendering it a very objectionable article of apparel, even in warm weather and in hot climates, where the dress is usually thin.

666. Clothing differs in its power of radiating heat. This is influenced by the color; those articles that radiate heat freely also absorb it readily. A black surface is a good radiator, while a white surface is not, because it reflects the calorific rays. It is obvious that those colors which render the transmission of external heat difficult, must impede the transmission of caloric from the body. Thus it is manifest, that light-colored apparel is best adapted for every season and every climate.

Observation. Coach-drivers are practically aware, that in cold weather, light-colored over-coats are warmest, except when they are exposed to the direct rays of the sun, or when seated before a warm fire. On the other hand, when the temperature is elevated, light-colored apparel is coolest, because the sun’s rays are then reflected.

665. What is said of linen as an article of apparel? 666. Why is light-colored apparel best adapted for every season? What is said of the apparel of coach-drivers? 667. Why should we wear porous clothing?

668. The necessity for this is illustrated in wearing India rubber over-shoes. If they are worn over boots ten or twelve hours, not only the hose, but the boots will be moist from retained perspiration, and the residual matter left in contact with the skin may be reconveyed into the system by absorption, causing headache and other diseases. Cotton and woollen fabrics are not only bad conductors of heat, but are also porous; for these reasons, they are well adapted to transmit the excretions of the skin.

669. The clothing should be not only porous, but fitted loosely. The garments should retain a layer of air between them and the body. Every one is practically aware that a loose dress is much warmer than one which fits closely; that a loose glove is warmer than a tight one; and that a loose boot or shoe affords greater warmth than one of smaller dimensions. The explanation is obvious; the loose dress encloses a thin layer of air, which the tight dress is incapable of doing; and what is required, is, that the dress should be closed at the upper part, to prevent the dispersion of the warm air, by the ventilating current which would be established from below.

Observation. As the purpose of additional garments is to maintain a series of strata of warm air within our clothing, we should, in going from a warm room into the cold air, put on our defensive coverings some little time previous, in order that the layers of air which we carry with us may be sufficiently warmed by the heat of the room, and not borrowed from the body on exposure to the cold.

668. How is the necessity of porous clothing illustrated? 669. Why should we wear loose garments? What is the use of additional garments when going from a warm to a cold air? When should they be put on?

670. The clothing should be suited to the temperature of the atmosphere and the condition of the individual. The invariable rule should be, to wear enough to maintain an equal and healthy action of the skin. Care should be taken, however, that the action of the cutaneous vessels is not inordinately increased, as this would debilitate, not only the skin, but the internal organs of the system, as the stomach and lungs.

671. No rule as to the quantity of clothing can be given, as the demand will vary with different individuals. The following are among the most prominent causes of this variation: Those persons who have large, active brains, full chests, well developed lungs, breathe an adequate amount of pure air, and take sufficient food to supply the wants of the system, require less clothing than those of an opposite character, because more heat is generated in the system.

672. The child and the aged person require more clothing than the vigorous adult. “Should we judge from observation, the inference would be, that children require less clothing than adults. This is an error, for the temperature in infancy is not only lower than in manhood, but the power of creating heat is feebler. The same remarks are applicable to those persons who have outlived the energies of adult life.”

670. What should be the invariable rule in reference to the amount of clothing that should be worn? What precaution should be observed? 671. What are some of the causes of the variation of the demand for clothing? 672. Why do the child and aged person require more clothing than the vigorous adult? What is said of the system of hardening children?

673. More clothing is needed when a vital organ is diseased. It may be observed that in consumption, dyspepsia, and even in headache, the skin is pale and the extremities cold, because less heat is generated. Thus persons affected with these complaints, when exposed to cold air, need more clothing than those individuals whose organs are not diseased, and the functions of which are properly performed.

674. More clothing is required in the evening, than during the day. In the evening we have less vital energy, and therefore less heat is generated in the system, than in the early part of the day; beside, the atmosphere is damp, the skin has become moist from free perspiration, and heat, in consequence, is rapidly removed from the system. For this reason, when returning from crowded assemblies, we should be provided with an extra garment.

Observations. 1st. If there is a chill upon the system after having arrived home, warmth should be restored as speedily as possible. This can be done by friction with warm flannels, and by using the warm or vapor bath. By this procedure, the pernicious effects of the chill will be prevented before any disease is fixed upon the system. Is it not the duty of the parent and the guardian to learn these facts, and to see that they are not only learned, but reduced to practice?

673. Why do dyspeptic and consumptive persons require more clothing than those who have healthy vital organs? 674. Why do we need more clothing in the evening than during the day? How can the pernicious effects of a chill be prevented? Give the 2d observation.

675. The person of active habits requires less clothing than one of sedentary employments. Exercise increases the circulation of the blood, which is always attended by the disengagement of a greater quantity of heat; consequently, an increase of warmth is felt throughout the system. We likewise need more clothing while riding, than when we are walking; because the exercise of the former is less than that of the latter. The same is true when resting in the field or shop, after laborious exercise.

Observation. We need a greater amount of clothing while asleep, than during the day; as not only the action of the body, but that of the brain, during sleep, is suspended.

676. Less clothing is required when the cutaneous surface is clean. A film of impurities obstructs the perspiratory ducts, and diminishes the action of their glands; consequently, less heat is generated. For this reason, the hands or feet when clean are less liable to become chilled or frozen.

675. Why does the person of active habits require less clothing than one of sedentary employments? 676. Why do we need less clothing when the skin is clean? 677. Show the effect of habit on the sensitiveness of the skin.

678. Those parts of the skin usually covered, uniformly need that protection. The power of generating heat is diminished, and the impressibility to cold is increased, on those portions of the skin usually clothed. If a person wears the dress high and close about the neck, he suffers from exposure to a cold atmosphere if a dress is worn that is not as high or more open. As a general rule, it is preferable that those parts of the system, as the larynx, be exposed that are not uniformly protected by clothing.

679. The clothing should be kept clean. No article of apparel is entirely free from absorption; even wool and cotton possess it in a small degree. They take up a portion of the transpired fluids which contain saline and animal matter, and thus the fibres of the garments become covered with the cutaneous excretions. We are practically aware of the retention of these secretions from the soiled appearance of those garments worn next the skin, which are so covered as to preclude the particles of dust from lodging upon them.

681. The under-garments worn during the day should not be worn at night, or the reverse. When under-garments are worn several successive days or nights, they should not be put in drawers, or hung up in a close closet, as soon as taken from the body, but should be exposed to a current of air.

682. Occupied beds should be thoroughly aired in the morning. The excretions from the skin are most abundant during the hours of sleep; and if the sheets and blankets, together with the bed, are not aired every morning, by being so arranged that both surfaces may be exposed to the air, the materials eliminated from the skin will be retained in the meshes of the bed-clothing, and may be conveyed into the system of the next occupant, by absorption. Oftentimes diseases of a disagreeable nature are contracted in this way. This fact should be instilled into every mother’s and daughter’s mind.

Observation. Bed-linen should not be put on a bed when it is not sufficiently dried, or contains moisture from the excretions of the skin, nor should beds or bedding be slept in, that have remained in a damp room that has not been occupied for many weeks, unless the dampness is removed from the bed-linen by a warming-pan, or in some other way.

681. Should the garments worn during the day be worn at night? 682. What is said respecting the cleanliness of beds and bedding? Why should not bed-linen that is damp be slept in? 683. When should change of dress from thick to thin be made? Why?

684. When the clothing has become wet, it is best to change it immediately. The skin should then be rubbed with a dry crash towel, until reaction, indicated by redness, is produced. If the garments are not changed, the person should exercise moderately, so that sufficient heat may continue to be generated in the system to dry the clothing and skin without a chill. Sitting in a cool shade, or current of air, should, by all means, be avoided; as colds are not contracted by free and excessive exercise, but by injudicious management after such exercise.

Observation. When an individual has been thrown into a profuse perspiration by violent exercise, though the skin and clothing may become wet, he feels no inconvenience from the dampness, as long as he continues that amount of exercise for the reason that the circulation of the blood being increased heat is generated in sufficient quantity to replace the amount abstracted from the system in evaporating the free perspiration; but as soon as the exercise is discontinued, the increased circulation subsides, and with it the extra amount of generated heat. This accounts for the chill we experience, when the damp clothing is permitted to dry on the body, after the cessation of exercise.

684. What suggestion when the clothing has become wet? What should be done if the garments are not changed? What causes the chill that is experienced when damp clothing is permitted to dry on the body?

685. Bathing, its necessity and expediency, is obvious from the structure and the functions of the skin. The cuticle is cast off in minute, powdery scales, many of which are retained upon the surface by the pressure of clothing. These mingle with the oily and saline products of the skin, and form a thin crust. This crust, on account of its adhesiveness, collects particles of dust and soot from the atmosphere, and particles of foreign matter from our dress; so that in the course of the day the whole body becomes coated with impurities. If this coating remains, becomes thick and established upon the skin, it will produce the following effects:—

686. 1st. The pores will be obstructed, consequently transpiration impeded, and the influence of the skin as an excretory entirely prevented. When the pores are obstructed, and transpiration is checked, the elements of the transpired fluids will necessarily be retained in the system; and, as they are injurious and poisonous if retained, they must be removed by those organs whose functions in the animal economy are similar, as the lungs, kidneys, liver, intestines, &c.

685. Show the necessity for bathing. 686. What effect upon the body if the pores of the skin are obstructed? 687. What is the effect when an organ not only performs its own specific function, but that of another?

688. 2d. The retained perspirable matter will irritate the skin, both mechanically and chemically; and this membrane will be kept damp and cold, from attraction and detention of moisture; and foreign material, as before adverted to, once removed from the system, may be reconveyed into it by absorption. As a consequence, cutaneous eruptions and diseases will be produced, and the re-absorption of matter once separated from the system, will be the exciting cause of other injurious disorders.

689. 3d. A film of foreign substance on the skin will inevitably become the seat of detention of miasmata and infectious vapors. These will remain until absorbed, and engender the diseases of which they are the peculiar cause. This is one reason why filthy persons contract infectious diseases more frequently than individuals of cleanly habits.

690. Bathing is useful to promote cleanliness. In this capacity, it enables us to remove the coating of impurities from the exterior of our persons. It effects this purpose by dissolving saline matters, and holding in temporary suspension those substances which are insoluble.

688. How are cutaneous eruptions frequently produced? 689. How are infectious vapors transmitted to the system? 690. How does bathing promote cleanliness? 691. Why is it necessary to use soap in bathing?

692. Every washing of the skin with soap removes the old face of the cuticle, and leaves a new one; and were the process repeated to excess, the latter would become so thin as to render the body sensible to impressions too slight to be felt through its ordinary thickness. On the other hand, when the cuticle and its accumulated impurities are rarely disturbed, the sensitiveness of the skin is impaired. The proper inference to be drawn from the preceding remarks, is in favor of the moderate use of soap to cleanse the skin.

Observation. If any unpleasant sensations are felt after the use of soap, they may be immediately removed by washing the surface with water slightly acidulated with lemon juice or vinegar, which neutralizes the alkali that may remain on the skin. This is effective treatment for “chapped hands.”

692. Why should only a moderate amount of soap be used in bathing? If unpleasant sensations are felt from too free use of soap, how can they be counteracted? 693. Give the different forms of bathing. What is the simplest mode of bathing? Can this mode be adopted by invalids with safety?

694. When the heat of the system is adequate, the bather may stand or sit in a shallow tub, while he receives the water from a sponge squeezed over the shoulders or against the body. In this form of bathing, the person is more exposed to the cold air, and on this account it is less suitable for very feeble individuals than the first-mentioned method. In the early use of this form of the sponge-bath, the bather should content himself with a single affusion from the sponge; the body should be quickly wiped with a soft towel, and friction applied with a crash towel or a brush.

695. The third kind of bathing is that of the shower-bath, which provides a greater amount of affusion than the former, combined with a greater shock to the nervous system. The concussion of the skin by the fall of water, particularly distinguishes this from the previous modes of bathing. The degree of concussion is modified by the size of the openings through which the water issues, and the height of the reservoir. The shower-bath admits of modification, adapting it to the most delicate as well as the robust. The extent of fall, the size of the apertures, the quantity and temperature of the water, may be regulated at pleasure.

Observation. In using the shower-bath, it would be judicious to commence with warm or tepid water, for which, by a gradual process, cold water may be substituted. In this way the system may be inured to cold water. After bathing, the skin should be wiped dry and rubbed briskly.

What is the test by which to estimate, the benefit of all modes of bathing? 694. Give another method of sponge-bathing. 695. What is said of the shower-bath? What caution is given? 696. Give the fourth form of bathing.

Observation. The length of time a person may remain in a cold bath with benefit varies from two to ten minutes; while a person may remain in a temperate, tepid, or warm bath, from ten to thirty minutes, or until special indications are exhibited.

697. In the vapor-bath, the vapor is not only applied to the exterior of the system, but it is inhaled and brought in contact with every part of the interior of the lungs. The bather is seated upon a chair, and the vapor gradually turned on around him, until the proper temperature (90° to 110°) is attained. The bath may be continued from ten to thirty minutes. After leaving the bath, attention should be given to the skin, as in other forms of bathing.

698. In order to increase and promote reaction of the skin, various measures and processes are used, some of which are practised in, and others after, quitting the bath. Of the former, the rubbing and brushing the skin are the most common and important. The brisk and efficient friction of the skin with a coarse towel and flesh-brush, after quitting the bath, should never be omitted. This short catalogue embraces all the appliances requisite for the purpose.

What degree of temperature of water is termed a cold bath? A temperate? A tepid? A warm? A hot bath? State the length of time that a person should remain in the different baths. 697. What is said of the vapor bath? 698. Mention the different methods for promoting reaction of the skin.

700. This condition of the skin is known by the redness of the surface, the glow, comfort, and warmth which follow the bath. The bather should direct all his care to insure this effect. By it the internal organs are relieved, respiration is lightened, the heart is made to beat calm and free, the mind is clear and strong, the tone of the muscular system is increased, the appetite is sharpened, and the whole system feels invigorated. This is the end and aim of the bather, and to this all his training tends. The error is, to expect the result without the preparation.

699. What is the effect upon the skin when cold water is applied? What is the first object and purpose of every form of bathing? 700. How is this condition of the skin known? Mention the salutary effects that this condition has on the body. 701. How should bathing be performed, in order to be efficient in preserving health?

702. In regard to the frequency of bathing, the face and neck, from their necessary exposure to the atmosphere, and the impurities which the latter contains, should receive at least two washings in twenty-four hours, one of which should be with soap; the feet, from the confined nature of the coverings which are worn over them, require at least one; the armpits, from the detention, as well as from the peculiar properties of the secretions, at least one; and the hands and arms, as many as seem proper. The whole person should be bathed at least every second day, but the most perfect health of every part of the body would be maintained, if the excretions from the skin were removed daily.

703. In diseases of the skin and internal organs, bathing is a remedial measure of great power. It should never be neglected or omitted. It is not only pleasant and safe, but is really more effective than any medicine administered internally. This, like other curative means, should be applied by the direction and under the eye of the medical adviser, that it may be adapted to the condition of the patient.

When should bathing be performed? 702. How often should we bathe? 703. What is said of bathing in disease? Who should direct the kind of bath proper in different diseases? 704. Were baths dedicated by the ancients?

705. The AIR is an agent of importance in the functions of the skin. It imparts to this membrane oxygen, and receives from it carbonic acid. It likewise removes from it a large portion of the perspiration and the more fluid portions of the oily secretion. In order that the air may accomplish these ends, it is necessary that it come in contact with the body. This is one of the many reasons why we should wear loose and porous clothing.

706. Again, the air should be pure, and free from redundant moisture. In the warm mornings of July and August, the air is loaded with moisture and impurities, and the perspirable matter is not removed from the system as it is when the air is pure and dry. This is the cause of the general lassitude that is experienced during such mornings. As soon as the fog is dispelled, these unpleasant sensations are removed. To sustain the functions of the skin in a healthy state, the parlor, kitchen, sleeping-room, school-house, and work-shop, should be well ventilated. The blood of the system will be purer, and its color of a brighter scarlet, if the skin is surrounded by fresh and pure air, than when it is foul or moist.

707. The LIGHT permeating the skin, not only exercises a salutary influence upon this membrane, but upon the blood, and, through this fluid, upon the whole system. For this reason, the kitchen and the sitting-room, which are the apartments most used by ladies, should be selected from the most pleasant and well-lighted rooms in the house. On the other hand, dark rooms and damp cellar-kitchens should be avoided, as exercising an injurious influence upon both body and mind.

705. Give the reasons why pure air should be supplied to the skin. 706. What is the cause of the general lassitude in a damp, warm morning? 707. Show the salutary effects of light on the skin. 708. What is one cause of disease and suffering in large villages?

709. Burns and SCALDS are terms applied to those conditions of the skin which are produced by the application of an undue amount of heat, which changes the action of its vessels.

710. A small degree of heat will irritate the nerves, and cause an increased action of the blood-vessels. This is attended with severe smarting pain, and will be followed by the deposition of serum under the cuticle, unless applications are made immediately, to prevent vesication, or blistering. To prevent or suppress this state of arterial action, wet some folds of cotton or woollen cloth with cold water, and apply them to the parts scalded; continue to apply cold water, so as to steadily maintain the low temperature of the applications, as long as the smarting pain is experienced. The steady application of cold dressing also tends to prevent an increased action of the blood-vessels, and will suppress it, if it already exist.

709. To what condition of the skin are the terms burns and scalds applied? 710. What is the effect when only a small degree of heat is applied to the skin? How can vesication be prevented? 711. What should be the treatment when blisters are formed?

712. If the cuticle has been removed, there will be much suffering, because the nerves are unduly stimulated by the air. The cuticle is the sheath or covering of the vessels and nerves of the skin, and when it is removed, a substitute should be applied. This substitute should be soothing, and cover the denuded surface. Linseed-meal or ground slippery-elm bark poultice, fresh cream, or lard and bees-wax, spread upon linen or cotton cloth, would make a good dressing. When dressings are applied, they should not be removed until they become dry and irritating.

713. If there is much suffering, administer to an adult from twenty-five to sixty drops of laudanum, according to the severity of the pain. If the patient is a child, from fifteen drops to a tea-spoonful of paregoric may be administered. When there is much prostration, some hot peppermint tea or other stimulant may be found necessary to bring on reaction.

714. The hands, feet, ears, &c., are subject, in cold latitudes, to be frozen, or frost-bitten. This may occur when the patient, at the moment, is not aware of it. The part affected at first assumes a dull red color, which gradually gives place to a pale, waxy appearance, and becomes quite insensible. The first thing to be done in such cases, is to reëstablish circulation. This should be effected very gradually. If a large quantity of blood is thrown suddenly into the chilled and debilitated vessels of the frozen part, inflammation may be produced that will destroy the vitality of the limb.

712. That should be the treatment if the cuticle has been removed? How often should the dressing of burns be removed? 713. What may be necessary when there is much suffering? 714. What is the appearance of limbs while freezing? How should the circulation be at first reëstablished? What should be avoided?

715. The circulation and sensibility may be restored by rubbing the frozen limb, with snow, or, when this is not to be obtained, cold water; but snow is always to be preferred. The fire should be avoided; and it would be better for the patient to be kept in a cold room, for a time, where there is no fire, or where the temperature is moderate.

716. When a person is found benumbed with cold, and almost or quite insensible, he should be taken into a cold room, the clothing removed, and friction commenced and continued for some time, with snow. When warmth begins to be restored, the individual should be rubbed with dry flannel, and the friction continued until reaction takes place.

Observation. When the toes and heels have been repeatedly chilled, there may be produced a disease called chilblains. This affection is attended with tenderness of the parts, accompanied with a peculiar and troublesome itching. The prevention of this disease is in wearing warm hose and thick shoes of ample size. Bathing the feet morning and evening is also a prevention of this disagreeable affection. When chilblains exist, apply cold water, warm camphorated spirits, or turpentine linament.

715. How may the circulation and sensibility be restored? 716. What treatment should be adopted when a person is benumbed with cold? What treatment should be adopted when warmth begins to be restored? What is said of chilblains?

717. The HAIRS are appendages of the skin, and, like the cuticle, they are a product of secretion. They have no blood-vessels or nerves, and, consequently, no vitality. The hairs take their origin from the cellular membrane, in the form of bulbs. Each hair is enclosed beneath the surface by a vascular secretory follicle, which regulates its form during growth. In texture, it is dense, and homogeneous toward the circumference, and porous and cellular in the centre, like the pith of a plant. Every hair has on its surface pointed barbs, arranged in a spiral manner, and directed toward the root of the hair; so that, if a hair be rolled between the fingers, it moves only in one direction.

717–723. Describe the appendages of the skin. 717. Why have not hairs vitality? Where do they take their origin? Give their structure. What is represented by fig. 118?

718. The color of the hair varies in different individuals, and is generally supposed to depend on the fluids contained in the pith. There are two causes which act in changing the hair gray. The first is, defective secretion of the coloring fluid. The second is, the canals, which convey the fluid into the hair, become obliterated. In the first instance, the hair will remain; in the second, it dies, and drops out; the cuticle of the scalp grows over the canal, which is soon obliterated, and the head becomes bald.

Observation. It is related that the hair of Marie Antoinette, Queen of France, and others, from excessive mental agitation, changed from black to gray in a single night. This is not strictly true; the secretion may be arrested, but that already deposited in the pith will require days or weeks to be removed.

719. Upon the upper part of the head, the oil-tubes open into the hair-sacs; consequently, the secretion of the oil-glands is spread over the surface of the hair, and not upon the cuticle. This is the cause of the dry, white, branny scales, called “scurf,” or “dandruff,” upon the head. This is natural, and cannot be prevented. When scurf exists, the only necessary application to remove it, is the frequent use of the hair-brush, and washing with pure water.

Observation. The secretion of the oil-glands may become impacted around the hairs as they issue from the skin, and thus prevent their outward movement in growing. The pressure of the matter deposited at their bulbs will then cause itching. The comb and the brush may be used to remove the impacted matter, and relieve the disagreeable sensation.

718. Upon what does the color of the hair depend? What are the causes of the hair becoming gray? What is the cause of the hair dropping out? What is related of Marie Antoinette? 719. How is “dandruff” on the scalp produced? What is the only necessary application to remove it? Give observation. 720. Where is the oil of the hair most abundant?

721. The uses of the hair vary in different regions of the body. Upon the head, it aids in shielding the brain from injury by blows, and it likewise serves to protect this part of the system from heat and cold, thus maintaining equal temperature of the cerebral organ. About the flections of the joints, as in the axilla, (armpit,) they prevent irritation of the skin from friction; in the passages to the ears and nostrils, they present an obstacle to the ingress of insects and foreign bodies; while in the eyebrows and eyelids, they serve to protect the organ of vision.