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Experiment. Read with the head bowed forward and the chin depressed; then read with the head erect and the chin elevated, and the difference in the movement of the vocal organs, together with the difference in the voice, will be manifest.
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601-616. Give the hygiene of the vocal organs. 602. How may the voice be strengthened? 603. What effect has the erect attitude upon the modulations of the voice? Give the experiment.
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604. If an individual or class read or sing when sitting, let the position represented by fig. 109 be adopted, and not the one represented by fig. 110; for the erect position in sitting conduces to the free and effective action of the respiratory and vocal organs, and is as important as the erect attitude in standing.
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604. What position should be adopted when a person reads or sings when sitting? Why?
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605. The muscles of the neck should not be compressed. If the muscles of the neck and larynx are compressed by a high cravat, or other close dressing, not only will the free and energetic movements of these parts be impeded, but the tones will be feeble and ineffective. Therefore the dress of the neck, particularly of public speakers and singers, should be loose and thin. For a warm dress upon the neck, when the vocal organs are in action, will induce too great a flow of blood to these parts, which will be attended by subsequent debility.
Observations. 1st. The loss of voice, (lar-yn-gi'tis,) which is prevalent among public speakers, may be ascribed in part to the injudicious dressing of the neck, and improper position in standing.
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605. How should public speakers dress their necks? Why? What is a common cause of the loss of voice?
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2d. When individuals have been addressing an audience in a warm room, or engaged in singing, they should avoid all impressions of a cold atmosphere, unless adequately protected by an extra garment.
606. The condition of the air modifies speaking and singing. As pure air is more elastic and resonant than impure, and as easy, melodious speaking or singing requires atmospheric elasticity, so school-rooms and singing-halls should be well ventilated, if we would be entertained with soft intonations in reading, or sonorous singing.
Observation. The imperfect ventilation of churches and vestries is another cause of laryngitis among clergymen. This affection is almost unknown among those who speak in very open rooms, where stoves are not used.
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Give 2d. observation. 606. Why does easy and melodious speaking require pure air? What is another cause laryngitis among clergymen?
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607. The condition of the nasal passages and throat modifies the voice. The enunciation of words is rendered more or less distinct, in proportion as the jaws are separated in speaking, and the fauces and nasal passages are free from obstruction. For these reasons, the scholar should be taught to open the mouth adequately when reading, speaking, or singing, that the sounds formed in the larynx and modified in the fauces may have an unobstructed egress.
Observations. 1st. If the fauces are obstructed by enlarged tonsils, (a condition by no means uncommon in children,) they should be removed by a surgical operation, which is not only effective, but safe, and attended with little suffering. The tonsils are situated on each side of the base of the tongue, and, when enlarged, they obstruct the passage through which the air passes to and from the lungs, and the respiration is not only laborious, but distressing.
2d. When the nasal passages are obstructed, there is a peculiar sound of the voice, which is called "talking through the nose." This phenomenon arises, not from the expired air passing through the nose, but from its not being able to pass through the nasal passages.
608. The state of the mind and health exerts an influence upon the vocal organs. "The organs of the voice, in common with all other parts of the bodily frame, require the vigor and pliancy of muscle, and the elasticity and animation of mind, which result from good health, in order to perform their appropriate functions with energy and effect. But these indispensable conditions to the exercise of vocal organs, are, in the case of most learners, very imperfectly supplied."
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607. Does the condition of the throat and nasal passages modify the voice? Name the influences that produce clear enunciation of words. What is the effect when the nasal passages are obstructed? 608. How are the vocal organs influenced? What do they require?
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609. "A sedentary mode of life, the want of invigorating exercise, close and long-continued application of mind, and, perhaps, an impaired state of health, or a feeble constitution, prevent, in many instances, the free and forcible use of those muscles on which voice is dependent. Hence arises the necessity of students of elocution practising physical exercises adapted to promote general muscular vigor, as a means of attaining energy in speaking; the power of any class of muscles being dependent on the vigor of the whole system."
610. "Gymnastic and calisthenic exercises are invaluable aids to the culture and development of the voice, and should be sedulously practised when opportunity renders them accessible. But even a slight degree of physical exercise, in any form adapted to the expansion of the chest and to the freedom and force of the circulation, will serve to impart energy and glow to the muscular apparatus of voice, and clearness to its sound."
611. "There is, therefore, a great advantage in always practising some preliminary muscular actions, as an immediate preparation for vocal exercises. The art of cultivating the voice, however, has, in addition to the various forms of corporeal exercise, practised for the general purpose of promoting health, its own specific prescription for securing the vigor of the vocal organs, and modes of exercise adapted to the training of each class of organs separately."
612. The results of such practice are of indefinite extent. They are limited only by the energy and perseverance of the student, excepting perhaps in some instances of imperfect organization. A few weeks of diligent cultivation are usually sufficient to produce such an effect on the vocal organs, that persons who commence practice with a feeble and ineffective utterance, attain, in that short period, the full command of clear, forcible, and varied tone.
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609. Why are students of elocution in general necessitated to practise physical exercise? 610. What are invaluable aids in the culture of the voice? 611. What is said of the art of cultivating the voice? 612. Are the results of such practices limited? What exception?
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613. Repetition is essential to distinct articulation of words. In teaching a child to articulate a letter or word, in the first instance, make an effort to induce a proper state of the vocal organs by which the particular sound is produced. Repeat the letter or word again and again, until all the parts of the vocal apparatus harmonize in their movements to produce the given sound. This repetition is as necessary in learning to read as in singing.
Observations. 1st. There is nothing gained by trying to teach a child to pronounce the letters of the alphabet, before the vocal organs are so developed that distinct utterance can be given to the proper sounds.
2d. The drawling method of talking to young children, as well as using words that are not found in any written language, (called child's talk,) is decidedly wrong. A child will pronounce and understand the application of a correct word as quickly as an incorrect one.
614. No part of the vocal organs is wanting, with those individuals that stammer, or who have an impediment in their speech. Some parts may be more developed than others, but they generally are but imperfectly under the control of the will, and assume an irregular and rapid movement, while other parts, the motions of which are essential, remain comparatively inactive. This can be seen by comparing the movements of the lips, tongue, and larynx, while attempting to speak, in a person who stammers, with the movements of the corresponding parts, while speaking, in an individual who has no such impediment.
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613. Is repetition essential to distinct articulation? What method is suggested in teaching a child to articulate letters or words? Give observation 1st. Observation 2d. 614. Are the vocal organs wanting in stammerers? Why the defect in their articulation of words?
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615. Surgical operations and medical treatment are not highly advantageous in a majority of these cases. In the young and middle aged, this defect can be remedied by patient and judicious training. At first, only those letters and words should be spoken that can be articulated with distinctness. Let there be repetition, until the words can be spoken at any time with readiness. Then take for a lesson other words, more difficult to articulate; and pursue a similar process of training and repetition, until every part of the vocal organs can be called into a ready and harmonious action in giving utterance to any word in common use.
616. The method of removing foreign bodies from the throat. It is not necessary to ascertain which passage the foreign body is in, for the immediate treatment ought in either case to be the same. Some person should place one hand on the front of the chest of the sufferer, and, with the other, give two or three smart blows upon the back, allowing a few seconds to intervene between them. This treatment will generally be successful, and cause the substance to be violently thrown from the throat.
Observation. If the foreign body passes into the larynx violent spasmodic coughing immediately succeeds, which continues until it is removed or life is extinct. Such cases demand the prompt opening of the trachea below the larynx by a skilful surgeon.
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615. How can stammering be remedied? 616. What is the method of removing foreign bodies from the throat?
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CHAPTER XXXI.
THE SKIN.
617. The skin is a membrane which envelops the muscles and other parts of the system. In youth, and in females particularly, it is smooth, soft, and elastic. In middle age, and in males, it is firm and rough to the touch. In old age, in persons who are emaciated, and about the flexions of the joints, it is thrown into folds. The interior of the body, like the exterior, is covered by a skin, which, from the constantly moistened state of its surface, is called the mucous membrane. At the various orifices of the body, the exterior skin is continuous with the internal.
ANATOMY OF THE SKIN.
618. The SKIN, to the naked eye, appears composed of one membrane. But examination has shown that it consists of two layers of membrane, namely, the Cu'ti-cle, (scarf-skin,) and the Cu'tis Ve'ra, (true skin.) These layers are widely different from each other in structure, and perform very different offices in the animal economy.
619. The CUTICLE (sometimes called the ep-i-derm'is) is the external layer of the skin. This membrane is thin and semi-transparent, and resembles a thin shaving of soft, clear horn, and bears the same relation to other parts of the skin that the rough bark of a tree does to the liber, or living bark. The cuticle has no perceptible nerves or blood-vessels; consequently, if it is cut or abraded, no pain will be felt, and no fluid will ooze from it.
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617. What is the skin? Mention its different appearances in its different conditions in the human frame. Is the interior of the body, as well as the exterior, covered by a skin? What is the interior membrane called? Why has it received this name? 618-636. Give the anatomy of the skin. 618. What is said of the skin? What is said relative to these layers of membrane? 619. Describe the cuticle. What name is sometimes applied to the cuticle?
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Experiment. Pass a pin through the portion of the cuticle that skirts the nails, or remove a thin shaving from the palm of the hand, and no painful sensation will be experienced unless the pin or knife penetrates deeper than the cuticle.
620. This membrane varies in thickness on different parts of the body,—from the thin, delicate skin upon the internal flexions of the joints, to the thickened covering of the soles of the feet. The greater thickness of the cuticle of the palms of the hands and soles of the feet, is manifestly the intentional work of the Creator; for it is perceptible in infants, even at birth, before exercise can have had any influence.
621. The CUTIS VERA (sometimes called the co'ri-on) is composed of minute fibres, which are collected into small bundles or strands. These are interwoven with each other so as to constitute a firm, strong, and flexible web. In the superficial part of the true skin, the web is so close as to have the appearance of felt-cloth; but more deeply, the pores become progressively larger, and, upon the lower surface, have a diameter of about a line, or one twelfth of an inch. This gives the under surface the appearance of a coarse web. The strands of the under surface of the true skin are connected with the fibrous web, in which the sub-cutaneous fat of the body is deposited; while the upper surface gives support to the sensitive, or papillary layer, which is bedded upon it.
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Give the experiment. 620. What is said of the thickness of the cuticle in different parts of the body? 621. Describe the cutis vera. By what name is it sometimes called? What is the appearance of the upper surface of the cutis vera? Of the under surface?
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Observation. When the skins of animals are immersed in a strong solution of oak or hemlock bark, a chemical union takes place between the gelatin, of which the true skin is mostly composed, and the tannin of the bark. By this process leather is formed, and its peculiar markings are owing to the papillary layer.
622. The sensitive layer of the skin is thin, soft, uneven, pinkish in hue, and composed of blood-vessels, which confer its various tints of red; and of nerves, which give it the faculty of sensation. The unevenness of this layer is produced by small, elongated, conical prominences, called Pa-pil'lae.
623. Each PAPILLA is composed of a minute artery, vein, and nerve. Some of the prominences are arranged in concentric ovals, as may be seen on the ends of the fingers; others are more or less parallel, and pursue a serpentine course; some suddenly diverge, and again reunite, as may be seen in the palm of the hand. Papillae are found in every part of the skin. Consequently, their number is very great.
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How is leather formed? 622. What is the appearance of the sensitive layer? What causes the unevenness of this layer? Explain fig. 111. 623. Describe the papillae.
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624. The cutis vera contains not only Arteries, Veins, and Nerves but Lymphatics, Oil-Glands and Tubes, and Perspiratory Glands and Tubes.
625. The ARTERIES AND VEINS of the skin are very numerous. The larger branches of the arteries pass through the open meshes of the true skin, and are subdivided into a myriad of minute capillary vessels, which form a beautiful net-work on the upper surface of the true skin. This vascular net sends a branch to each of the papillae, which opens into and terminates in a minute vein. The capillary veins are as numerous as the arteries which they accompany. They unite and form larger trunks, as small springs from the hill side coalesce to form rivulets.
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624. What vessels are found in the cutis vera? Explain fig. 112. 625. What is said of the cutaneous arteries? Of the cutaneous veins?
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626. The NERVES that are spread over every part of the sensitive layer of the true skin, proceed from the spinal cord. As a proof of the great number of nervous filaments in the skin, no part of this tissue can be punctured with a fine needle without transfixing a nerve, and inducing pain. In some parts of the system, however, the nerves are more abundant than in others; where the sense of feeling is most acute, we find the greatest number of nerves, and those of the largest size. Those parts that are most exposed to injury are most sensitive.
Examples. 1st. The conjunctiva, or skin of the eye, is pained by the presence of a particle of dust, because it would render vision imperfect.
2d. The lungs, also, would be injured by the smallest particle of matter; they are therefore protected by the exquisite sensitiveness of the lining membrane of the trachea, so that a particle of food or dust is ejected by a convulsive cough before it reaches the lungs.
627. The nerves are more numerous in the upper than lower extremities; in greater numbers upon the palm than the back of the hand. They are, likewise, more abundant and larger at the extremities of the fingers, and in the lips, than in any other part of the skin.
Observation. The proboscis of the elephant, the extremities of the tails of certain species of monkeys, and the tentacula of some kinds of fish, receive a more abundant supply of sensitive nerves than other parts of their systems.
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626. Where do the nerves of the skin proceed from? Are they numerous in this membrane? How is it proved? What is said of those parts most exposed to injury? Give example 1st. Example 2d. 627. Mention the difference in the distribution of the nerves in various parts of the body. Is this difference found in the lower order of animals?
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628. In the small papillae, the nerve forms a single loop, while in papillae of larger size, and endowed with a power of more exalted sensation, the nerve is bent several times upon itself previous to completing the loop. These little loops spring from a net-work of nerves, imbedded in the upper porous layer of the true skin, at the base of the papillae. This net-work of nerves receives its influence through nerves which take their winding course through the fat distended openings of the deeper layers of the true skin.
629. The LYMPHATICS are found in great numbers in the true skin, and they are so minute that they cannot be seen with the naked eye; but when these hair-like vessels are injected with quicksilver, (a work of great difficulty,) the surface injected resembles a sheet of silver. In this way their existence can be imperfectly demonstrated. They are a part of the vascular net-work situated upon the upper surface of the true skin. Each papilla is supplied with a lymphatic filament, the mouth of which opens beneath, and lies in contact with the under surface of the cuticle. This net-work of vessels communicates through the open meshes of the true skin with larger lymphatic trunks, that open into the venous system.
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628. How are the nerves of the small papillae arranged? How in the large papillae? What does fig. 113 represent? 629. What is said of the cutaneous lymphatics? How is their existence proved?
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630. The OIL-GLANDS are small bodies imbedded in the true skin. They connect with the surface of the skin by small tubes, which traverse the cuticle. In some parts, these glands are wanting; in others, where their office is most needful, they are abundant, as on the face and nose, the head, the ears, &c. In some parts, these tubes are spiral; in others, straight. These glands offer every shade of complexity, from the simple, straight tube, to a tube divided into numberless ramifications, and constituting a little rounded tree-like mass, about the size of a millet seed.
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Of what are they a part? 630. Describe the oil-glands. With what do they connect? Do they exist in every part of the body? Of what form are their tubes?
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631. In a few situations, these small glands are worthy of particular notice, as in the eyelids, where they possess great elegance of distribution and form, and open by minute pores along the lids; in the ear-passages, where they produce that amber-colored substance, known as the ce-ru'men, (wax of the ears,) and in the scalp, where they resemble small clusters of grapes, and open in pairs into the sheath of the hair, supplying it with a pomatum of Nature's own preparing. The oil-tubes are sometimes called the se-ba'ceous fol'li-cles.
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631. What is said of these tubes in the eyelids? In the ear? In the scalp? What are these glands sometimes called?
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Observation. Among the inhabitants of cities, and especially in persons who have a torpid state of the skin, the contents of the oil-tubes become too dense and dry to escape in the usual manner. Thus it collects, distends the tube, and remains until removed by art. When this impacted matter reaches the surface, dust and smoke mix with it, then it is recognized by small, round, dark spots. These are seen on the forehead, nose, and other parts of the face. When this matter is pressed out, the tube gives it a cylindrical form. The parts around the distended tubes sometimes inflame. This constitutes the disease called, "ac'ne punc-ta'ta."
632. The PERSPIRATORY APPARATUS consists of minute cylindrical tubes, which pass inward through the cuticle, and terminate in the deeper meshes of the cutis vera. In their course, each little tube forms a beautiful spiral coil; and, on arriving at its destination, coils upon itself in such a way as to constitute an oval-shaped, or globular ball, called the perspiratory gland.
633. The opening of the perspiratory tube on the surface of the cuticle, namely, "the pores," is also deserving of attention. In consequence of its extremity being a section of a spirally-twisted tube, the aperture is oblique in direction, and possesses all the advantages of a valvular opening, preventing the ingress of foreign injurious substances to the interior of the tube and gland.
634. "To arrive at something like an estimate of the value of the perspiratory system, in relation to the rest of the organism, I counted the perspiratory pores on the palm of the hand, and found 3528 in a square inch. Now each of these pores being the aperture of a little tube about a quarter of an inch long, it follows, that in a square inch of skin on the palm of the hand there exists a length of tube equal to 882 inches, or 73 1/2 feet. Surely such an amount of drainage as seventy-three feet in every square inch of skin—assuming this to be the average for the whole body—is something wonderful and the thought naturally intrudes itself, What if this drainage be obstructed?
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What is said of the retention of the unctuous matter in the oil-tubes? 632. Of what does the perspiratory apparatus consist? 633. What is peculiar in the opening of the perspiratory tubes on the surface of the cuticle? 634. How many perspiratory pores did Dr. Wilson count upon a square inch of skin on the palm of the hand?
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What does fig. 116 represent?
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635. "Could we need a stronger argument for enforcing the necessity of attention to the skin? On the pulps of the fingers, where the ridges of the sensitive layer of the true skin are somewhat finer than in the palm of the hand, the number of pores on a square inch a little exceeded that of the palm; and on the heels, where the ridges are coarser, the number of pores on the square inch was 2268, and the length of the tube 567 inches, 47 1/4 feet.
636. "To obtain an estimate of the length of tube of the perspiratory system of the whole surface of the body, I think that 2800 might be taken as a fair average of the number of pores in the square inch; and consequently, 700, the number of inches in length. Now, the number of square inches of surface in a man of ordinary height and bulk is 2500; the number of pores, therefore, 7,000,000; and the number of inches of perspiratory tube is 1,750,000; that is, 145,833 feet, or 48,611 yards, or nearly TWENTY-EIGHT miles!"—Wilson.
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Give other computations in this paragraph. 635. What is said of the number of these pores on the pulp of the fingers? On the heels? 536. What is an average number of pores and length of tube of the whole surface of the body? Give the summary of the number of pores, and number or inches of perspiratory tube.
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CHAPTER XXXII.
PHYSIOLOGY OF THE SKIN.
637. The skin invests the whole of the external surface of the body, following all its prominences and curves, and gives protection to all the organs it encloses, while each of its several parts has a distinct use.
638. The cuticle is insensible, and serves as a sheath of protection to the highly sensitive skin (cutis vera) situated beneath it. The latter feels; but the former blunts the impression which occasions feeling. In some situations, the cuticle is so dense and thick, as wholly to exclude ordinary impressions. Of this we see an example in the ends of the fingers, where the hard and dense nail is the cuticle modified for the purpose referred to. Were the nervous tissue of the true skin not thus protected, every sensation would be so acute as to be unpleasant, and contact with external bodies would cause pain.
639. The cuticle, also, prevents disease, by impeding the evaporation of the fluids of the true skin, and the absorption of the poisonous vapors, which necessarily attend various employments. It, however, affords protection to the system only when unbroken, and then, to the greatest degree, when covered with a proper amount of oily secretion from the oil-glands.
640. The cuticle is, originally, a transparent fluid, exuded by the blood-vessels, and distributed as a thin layer on the surface of the true skin. While successive layers are formed on the exterior of the true skin, the external cuticular layers are converted into dry, flattened scales, by the evaporation of their fluid contents. The thickness of the cuticle is formed mainly from these scales.
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637-656. Give the physiology of the skin. 637. What is said of the skin? 638. Give a function of the cuticle. Does it vary in thickness on different parts of the body? Give examples. 630. Mention another use of the cuticle. 640. What is the cuticle originally?
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641. The cuticle is, therefore, undergoing a constant process of formation and growth at its under part, to compensate for the wear that is taking place continually on its surface. A proper thickness of the cuticle is in this manner preserved; the faculty of sensation and that of touch are properly regulated; the places of the little scales, which are continually falling off under the united influence of friction and ablution, are supplied; and an action necessary, not merely to the health of the skin, but to that of the entire body, is established.
642. Whenever the cuticle is exposed to moderate and repeated friction, it becomes thicker and tougher, as may be seen in the cuticle of the lady's finger that plies the needle and in the hard or callous appearance of the hands of farmers masons, and other mechanics. This enables them to handle the utensils and materials used in their vocations without pain or inconvenience.
Observations. 1st. When the joints of the feet are subjected to moderate and continued pressure or friction, frequently one or more of the papillae enlarge. This is accompanied with a thickening of the layers of the cuticle, which is termed a "callosity," or "corn." These thickened layers of the cuticle are broad at the top and narrow at the bottom, and the enlarged mass is conical, with the point innermost. When pressed upon by a tight shoe, these sensitive papillae cause pain.
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How is the thickness of the cuticle mainly formed? 641. Describe the changes of this membrane. Show the necessity of this constant growth. 642. How does moderate and repeated friction affect the cuticle? Give examples. What is the benefit derived from having the cuticle thus changed? What is the result if the joints of the feet are subjected to moderate and continued pressure? What is the form of a "corn"?
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2d. To remove these painful excrescences, take a thick piece of soft leather, somewhat larger than the corn; in the centre punch a hole of the size of the summit of the corn, spread the leather with adhesive plaster, and apply it around the corn. The hole in the leather may be filled with a paste made of soda and soap, on going to bed. In the morning, remove it, and wash with warm water. Repeat this for several successive nights, and the corn will be removed. The only precaution is, not to repeat the application so as to cause pain.
643. Let a person unaccustomed to manual labor, trundle the hand-cart, or row a boat, for several successive hours, and the cuticle upon the palms of the hands, instead of becoming thicker by use, is frequently separated from the subjacent tissues, by an effusion of serum, (water,) thrown out by the vessels of the true skin. Had the friction been moderate, and applied at regular intervals, instead of blisters being formed upon the inside of the hands, material would have been thrown out to form new layers upon the lower surface of the cuticle.
644. The cuticle is interesting to us in another point of view, as being the seat of the color of the skin. The difference of color between the blonde and the brunette, the European and the African, lies in the cuticle;—in the deeper, and softer, and newly-formed layers of that structure. In the whitest skin, the cells of the cuticle always contain more or less of a peculiar pigment, incorporated with the elementary granules which enter into their composition. In the white races, the pigmentary tint is extremely slight, and less in winter than in the summer season. In the darker races, on the contrary, it is deep and strongly marked.
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How can they be removed? What precaution is given? 643. Explain why those persons unaccustomed to labor, blister their hands in rowing a boat or performing ordinary manual employment for several successive hours. 644. In what other point of view is the cuticle interesting? In what part of it do we find the coloring matter?
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645. The various tints of color exhibited by mankind, are, therefore, referable to the amount of coloring principle contained within the elementary granules of the cuticle, and their consequent depth of hue. In the negro, the granules are more or less black; in the European of the south, they are amber-colored; and in the inhabitants of the north, they are pale and almost colorless.
646. Color of the skin has relation to energy in its action; thus, in the equatorial region, where light and heat are most powerful, the skin is stimulated by these agents to vigorous action, and color is very deep; while in the temperate regions, where light and heat are not so intense, the lungs, liver, and kidneys relieve the skin of part of its duties. The colored layer of the cuticle has been called the re'te mu-co'sum, (mucous coat of the skin,) and described as a distinct layer by many physiologists.
Observation. "The various coloring of the inner layer of the cuticle gives to some animals their varied hues; the serpent, the frog, the lizard, and some fishes have a splendor of hue almost equal to polished metal. The gold-fish and the dolphin owe their difference of color and the brilliancy of their hues to the color of this layer of the skin."
647. The nerves of the skin are the organs of the sense of touch and feeling. Through them we receive many impressions that enhance our pleasures, as the grateful sensations imparted by the cooling breeze in a warm day. In consequence of their sensitiveness, we are individually protected, by being admonished of the proximity of destructive agents.
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In what season of the year is the coloring matter less in the white race? 645. To what is the color of the skin referable? 646. Why have the races of the torrid zone darker complexions than those of the temperate or frigid zones? What is this colored layer called by many physiologists? To what is the different hues in animals owing? 647. Of what use are the nerves of the skin?
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Illustration. A man who had been afflicted some years with a severe disease of a portion of the brain and spinal cord, was deprived of feeling in the lower extremities. He was directed by his attending physician to use a warm footbath. Intending to follow the directions given him, he immersed his feet in boiling water, which he supposed of a proper temperature. While his feet were immersed in the water, he experienced no sensation of an unpleasant nature. On withdrawing them, he was astonished to find the cuticle separated from the other tissues, by the effusion of serum, and thus producing a blister over the whole surface.
648. Portions of the skin would suffer every day, were it not for the sentinel-like care exercised by the nerves, by which all impressions are transmitted to the brain. As the skin is continually exposed to the influence of destructive agents, it is important that the nerves, provided for its protection, should be kept in a healthy state.
649. A large proportion of the waste of the body passes through the outlets of the skin; some portions in the form of oil, others in the form of water and carbonic acid.
650. The oil-glands secrete an oil, partly free and diffused, and partly mixed with albumen. When the cells are fully formed, that is, fully distended, they yield their contents, and the fluid matter they contain is set free, and passes along the tubes to the surface; this fluid matter constitutes the oily element of the economy of the skin.
651. The uses of the unctuous product of the oil-glands are twofold: 1st. The protection; 2d. The removal of waste matter from the system. In the exercise of these offices the oily substance is diffused over those parts of the skin which are naturally exposed to vicissitudes of temperature and moisture,—as the nose, face, and head;—to the injurious attrition of contiguous surfaces,—as the flexures of joints;—or the contact of acrid fluids,—as in the excoriations to which infants are liable.
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Give the illustration. 648. Why is it necessary that the cutaneous nerves be kept in a healthy state? 649. Through what membrane does a large proportion of the waste material of the system pass? 650. What is the function of the oil-glands? 651. What are the uses of the oily product of these glands?
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652. The oil of the unctuous substance is the principal agent in effecting these purposes: 1st. It prevents the evaporation or congelation of the water of the cuticle, which would cause it to become parched and peel off, thus leaving the sensitive skin exposed. 2d. It affords a soft medium to the contact of moving substances. 3d. It repels moisture and fluids. 4th. The action of these glands removes the waste atoms and purifies the blood.
653. In considering the purpose of the oily matter of the skin, there are two situations in which it deserves especial remark. 1st. Along the edges of the eyelids, where it is poured out in considerable quantity. Here, it is the means of confining the tears and moisture of the eyes within the lids, defending the skin from the irritation of that fluid, and preventing the adhesion of the lids, which is liable to occur upon slight inflammation. 2d. In the ears, where the unctuous wax not only preserves the membrane of the drum and the passage of the ear moist, but also, by its bitterness, prevents the intrusion of small insects.
654. The use of the perspiratory glands is to separate from the blood that portion of the waste matter which is carried off through the skin in the form of vapor. Sanctorius, a celebrated medical writer, daily, for thirty years, weighed himself, his food, and excretions. He estimated that five of every eight pounds of food and drink passed from the system through the many outlets upon the skin. Many place the estimate much lower. All physiologists agree that from twenty to forty ounces of matter pass off from the skin of an adult every twenty-four hours.
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652. What prevents the evaporation of the water of the cuticle? Give its 2d use. Its 3d. Its 4th. 653. What is said in reference to the distribution of the oily matter along the edges of the eyelids? In the ears? 654. Of what use are the perspiratory glands? How long did Sanctorius daily weigh his food, to ascertain the amount of secretion that passed through the skin?
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655. The average amount of perspiration is about thirty ounces; and it passes off in such minute portions, and mixes so rapidly with the surrounding air, that it is not perceived. For this reason, it is called insensible perspiration. When this excretion is increased, it forms into drops, and is called sensible perspiration. The following experiments prove the existence of this excretion from the skin.
Experiments. 1st. Take a cold bell-glass, or any glass vessel large enough to admit the hand, and introduce it perfectly dry; at the same time close the mouth by winding a napkin about the wrist; in a short time, the insensible perspiration from the hand, will be seen deposited on the inside of the glass. At first, the deposit is in the form of mist; but, if the experiment be continued a sufficient time, it will collect in drops.
2d. Hold the apparently dry hand near a looking-glass, and the invisible vapor will soon be condensed, and cover the glass with a slight dew.
656. It is important that this excretion be maintained with steadiness and regularity. When the action of the perspiratory glands is suppressed, all the vessels of the different organs will suffer materially, and become diseased, by the redundant waste matter that should be carried from the system. If a person is vigorous, the action of the organs, whose functions are similar to those of the skin, as channels for the exit of waste matter, will be increased, and thus relieve the diseased state of the body. But the over-taxing of these organs, to relieve the system, often produces a diseased action in themselves.
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What were his conclusions? 655. What is the average amount of perspiration every twenty-four hours? What is insensible perspiration? What is sensible perspiration? How can the existence of the excretion of the skin be shown? Give the 2d experiment. 656. Why is it important that these excretions be maintained regularly?
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[Illustration: Fig. 117. 1, 1, The lines, or ridges of the cuticle, cut perpendicularly. 2, 2, 2, 2, 2, The furrows, or wrinkles of the same. 3, The cuticle. 4, 4, 4, The colored layer of the cuticle. 5, 5, The cutis vera. 6, 6, 6, 6, 6, The papillae. 7, 7, Small furrows between the papillae. 8, 8, 8, 8, The deeper furrows between each couple of the papillae. 9, 9, Cells filled with fat. 10, 10, 10, The adipose layer, with numerous fat vesicles. 11, 11, 11, Cellular fibres of the adipose tissue. 12, Two hairs. 13, A perspiratory gland, with its spiral duct. 14, Another perspiratory gland, with a duct less spiral. 15, 15, Oil-glands with ducts opening into the sheath of the hair, (12.)]
Note.—Let the pupil review the anatomy and physiology of the skin from Fig. 117 or from anatomical outline plate No. 9.
CHAPTER XXXIII.
HYGIENE OF THE SKIN.
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.
660. The material for clothing should not possess the property of absorbing and retaining moisture. Dampness, or moisture, renders apparel a good conductor of heat; beside, if the perspired fluid, and the saline material it holds in solution, are readily absorbed by the clothing, they become sources of irritation to the skin with which the apparel comes in contact.
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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?
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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.
664. Silk is not as good a conductor of heat as cotton, nor does it absorb moisture to any considerable degree; its texture is smooth, and does not irritate the skin; consequently, when the garment of this fabric has sufficient body or thickness, it is a good article for clothing. The greatest objection to its use is the disturbance of the electricity of the system, and its high price.
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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?
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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.
667. The clothing should be of a porous character. The skin is not only an important agent in separating from the blood those impurities that otherwise would oppress the system and occasion death, but it exercises great influence upon the system, by receiving oxygen through its tissues, and giving back carbonic acid in return. Consequently, the apparel should be made of a material that will permit free transpiration from the skin, and likewise convey the excreted fluids from the surface.
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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?
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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.
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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?
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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."
Observation. The system of "hardening" children, by an inadequate supply of clothing, and keeping them uncomfortably cold throughout the whole day, is inhuman, as well as unprofitable. It operates upon the child somewhat like the long-continued chill upon a certain portion of the farmer's herd, that are kept shivering under the thatched shed, retarding the growth of their systems, which require more food to satisfy the keen cravings of hunger than when they are comfortably sheltered. To make the boy robust and active, he must have nutritious food at stated hours, and free exercise in the open air, and his system must be guarded from chills by a due amount of apparel.
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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?
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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?
2d. The farmer and industrious mechanic would be freed from many a rheumatic pain, if, while resting from their labors at evening, or taking the ordinary meal after hard toil, they would put on an extra garment. The coat might not feel so agreeable for the first few minutes, but it would ultimately conduce to health and longevity.
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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.
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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.
677. The sensitiveness of the skin to the influence of cold, is much modified by habit. A person who has been habituated to the temperature of a warm room, or warm climate, suffers more when exposed to cold, than an individual who has been accustomed to colder air. Thus a person who labors or studies in a warm room, should wear more clothing when exposed to the air, while walking or riding, than an individual who labors in a cooler atmosphere. Not only is the sensibility of the skin increased by a warm atmosphere, but the activity of the digestive, respiratory, and nervous systems, in generating heat, is much diminished. This is an additional reason why an increased amount of clothing is demanded during exposure to cold air. In all cases where practicable the heat of the system should be maintained by exercise, in preference to the use of fur or flannel.
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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.
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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.
680. The porosity of the clothing is lessened when soiled, and its power of conducting heat from the system in consequence, is increased. The residual matter with which the clothing is coated is brought in contact with the skin, which causes irritation, and not unfrequently re-absorption of the elements, thrown off from the system through this avenue. Hence warmth, cleanliness, and health require that the clothing, particularly the garments worn next to the skin, should be frequently and thoroughly washed. This should not be forgotten in regard to children, for their blood circulates with greater rapidity than that of adults, and a proportionably greater amount of waste matter is thrown off from their systems.
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.
683. Changes of dress, from thick to thin, should always be made in the morning. At this time the vital powers are usually in full play. Many a young lady has laid the foundation of a fatal disease, by disregarding this rule, in exchanging the thick dress, with woollen stockings, for the flimsy dress and hose of silk or cotton, which are considered suitable for the ball-room or party. Sudden changes in wearing-apparel, as well as in food and general habits, are attended with hazard; and this is proportionate to the weakness or exhaustion of the system when the change is made.
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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?
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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.
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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?
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CHAPTER XXXIV.
HYGIENE OF THE SKIN, CONTINUED.
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.
687. When these organs are called upon to perform their offices, and in addition that of another, the healthy equilibrium is destroyed, and the oppressed organ will suffer from exhaustion, and become the prey of disease. Thus, obviously, habits of uncleanliness are a cause of consumption and other serious diseases of the vital organs. Again, obstruction of the pores will prevent respiration through the skin, thus depriving the blood of one source of its oxygen, and one outlet of its carbonic acid, which will diminish the temperature of the system, and the same results follow as when the clothing is inadequate.
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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?
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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.
691. The cuticle is composed of a substance resembling the dried white of egg, or, in a word, albumen. This is soluble in alkalies, and these are the agents which are commonly employed for purifying the skin. Soap is a compound of the alkali soda with oil, the former being in excess. When used for washing, the excess of alkali combining with the oily fluid, with which the skin is naturally bedewed, removes it, in the form of an emulsion, and with it a portion of any adhering matter. Another portion of the alkali softens and dissolves the superficial layer of the cuticle; and when this is removed the cuticle is free from impurities.
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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?
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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."
693. Bathing may be partial or general, and the water used may be cold, temperate, tepid, warm, or hot. A person may apply it to his system with a sponge, it may be poured upon him, or he may immerse himself in it. The simplest mode of bathing is to apply water to a small extent of surface, by means of a wet sponge, and after being wiped dry, again cover with the dress. In this way the whole body may be speedily subjected to the influence of water, and to no less useful friction. The water used may be warm or cold. This species of bathing may be practised by any invalid, and always with benefit, if the bathing is succeeded by a glow of warmth over the surface; and this is the test by which the benefit of all forms of bathing is to be estimated.
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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?
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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.
696. The fourth form of bathing is that in which the body, or a portion of it, is immersed in water. The temperature of water in this form of bathing may be modified according to the sensations and purposes of the bather. This form of bathing is designated according to the heat of the water. When the temperature is below 75 deg., it is termed a cold bath; when from 75 deg. to 85 deg., a temperate bath; from 85 deg. to 95 deg., a tepid bath; from 95 deg. to 98 deg., a warm bath; from 98 deg. to 105 deg., a hot bath. In using this form of bathing, the skin should be wiped perfectly dry, and briskly rubbed.
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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.
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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 deg. to 110 deg.) 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.
699. Bathing promotes health by its immediate and remote physiological effects on the system. When the body is moistened with a sponge wet with cold water, or when an affusion by the sponge or shower-bath is used, the skin instantly shrinks, and the whole of its tissue contracts. This contraction diminishes the capacity of the cutaneous system of blood-vessels, and a portion of the blood circulating through them is suddenly thrown upon the more internal parts of the body. The nervous system, among others, participates in it, and is stimulated by the afflux, and communicates its stimulus to the whole system. This causes a more energetic action of the heart and blood-vessels, and a consequent rush of blood back to the skin. This is the state termed reaction, the first object and purpose of every form of bathing.
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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.
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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.
701. In order to promote reaction, and to be efficient in preserving health, bathing should be regular, should be commenced by degrees, and increased by a process of training, and should not be permitted to intrude upon hours devoted to some important function, as digestion. It must not precede or follow too closely a meal, or severe mental or muscular exercise, as reaction is less certain and vigorous when important internal organs are employed, than when they are at rest. When the vital powers are greatest, and the system most free from exhaustion, bathing is most beneficial; hence the morning is preferable to the evening, and the middle of the forenoon to the middle of the afternoon, for this healthful and agreeable duty; as the vital action of the system is most energetic in the early part of the day.
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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?
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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.
704. "From the first hour of man's existence to his latest breath, in health and in sickness, rich or poor, water is always requisite. Baths were dedicated by the ancients to the divinities of medicine, strength, and wisdom, namely, AEsculapius, Hercules, and Minerva, to whom might properly be added the goddess of health, Hygeia. The use of water has been enforced as a religious observance, and water has been adopted as one of the symbols of Christianity."
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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?
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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.
708. The dark, damp rooms, so much used in cities and large villages, by indigent families and domestics, are fruitful causes of disease, as well as of vice, poverty, and suffering. Common observation shows that solar light also exercises much influence upon the vigor and color of vegetables. Plants that are kept in well-lighted rooms, have darker and more brilliant colors than those that grow in darkened apartments.
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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?
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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.
711. When blisters are formed, the cuticle is separated from the other tissues of the skin by the effusion of serum. In all cases, if this layer of the skin is not removed, a small opening should be made in the raised cuticle, by which the serum deposited may be removed. Under such circumstances, never remove the cuticle, as it makes the best possible covering for the blood-vessels and nerves of the true skin. The cold water dressing, recommended in the preceding paragraph, may then be applied as long as the smarting sensation continues. After the pain has subsided, the blistered part may be covered by a patch of cotton or linen cloth, upon which an ointment, made of lard and bees-wax, has been spread.
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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?
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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 reestablish 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.
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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 reestablished? What should be avoided?
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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.
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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?
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CHAPTER XXXV.
APPENDAGES OF THE SKIN.
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.
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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?
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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.
720. The oil is most abundant near the roots of the hair A free use of the brush spreads it along the hairs, and gives them a smooth, glossy appearance. Soap should rarely be used in washing the head, as it will remove the oil which is essential to the health and appearance of the hair.
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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?
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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.
722. The NAILS are hard, elastic, flexible, semi-transparent scales, and present the appearance of a layer of horn. The nail is divided into the root, the body, and the free portion. The root is that part which is covered on both surfaces; the body is that portion which has one surface free; the free portion projects beyond the end of the finger.
723. The nail is formed of several laminae, or plates, that are fitted the one to the other; the deepest is that which is last formed. The nails, as well as the hoofs of animals and the cuticle, are products of secretion. They receive no blood-vessels or nerves. If the cuticle be removed in severe scalds they will separate with it, as the hoofs of animals are removed by the agency of hot water. The nails increase in length and thickness, by the deposition of albumen upon their under surface, and at their roots, in a manner similar to the growth of the cuticle, of which they constitute a part.
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How can it be spread along the hairs? Why should soap not be used in washing the hair? 721. Of what use is the hair upon the head? About the flexions of the joints? In the nasal and ear passages? Upon the eyebrows and eyelids? 722. Describe the nails. 723. How are they formed?
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Observations. 1st. The nail upon its under surface is fashioned into thin vertical plates, which are received between the folds of the sensitive skin. In this manner, the two kinds of laminae reciprocally embrace each other, and the firmness of connection of the nail is maintained. If we look on the surface of the nail, we see an indication of this structure in the alternate red and white lines which are there observed. The former of these correspond with the sensitive laminae; the latter with the horny plates. The ribbed appearance of the nail is due to the same circumstance. These sensitive laminae are provided with an unusual number of capillary vessels for the formation of the nail, and hence they give a red tint to the portion under which they lie.
2d. Near the root of the nail there is a part that is not laminated, and it is less abundantly supplied with blood-vessels. This portion consequently looks pale compared with the laminated portion, and from its half-moon shape is technically termed lunula. Beyond the lunula, the root of the nail is imbedded in the fold of the sensitive skin, and has the same relation to that structure that any single one of the thin horny plates of its under surface has to its corresponding pair of sensitive laminae.
724. The nails, from their position, are continually receiving knocks, which produce a momentary disturbance of their cell formation, followed by a white spot. The care of the nails should be strictly limited to the knife or scissors, to their free border, and an ivory presser, to prevent adhesion of the free margin of the scarf-skin to the surface of the nail. This edge of the cuticle should never be pared, the surface of the nail never scraped, nor the nails cleaned with any instrument whatever, except the nail-brush, aided by water and soap. An observance of these suggestions, will prevent irregularities and disorders of the nails.
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Give observation 1st. Observation 2d. 724. How should the nails be treated to prevent irregularities and disease?
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Observations. 1st. When we wear a shoe that is too short for the foot, the edge of the nail is brought against the leather. This interrupts the forward growth of the nail, and it spreads out on the sides, and becomes unusually thick. It then presses upon the soft parts, and is said to "grow into the flesh." The prevention is, to wear shoes of ample size.
2d. Instances are by no means unfrequent in which the power of production of the nail at the root becomes entirely destroyed, and it then grows in thickness only. When this affection occurs, it is often remarkable what a mass the nail presents. Instances are on record, where the nail is regularly shed; and, whenever the old nail falls off, a new one is found beneath it, perfectly formed. Sometimes the growth in length is not entirely checked, although growth in thickness is induced; the nail then presents a peculiar appearance.
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What causes the edge of the nail "to grow into the flesh" of the toe? How prevented?
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CHAPTER XXXVI.
THE NERVOUS SYSTEM.
725. In the preceding chapters, we have seen how various and complex are many of the motions necessary to maintain the life of an animal whose organization is superior to all others. We have noted the wonderful mechanism of the muscular system, in producing the varied movements of the body, the different processes by which the food is converted into chyle and mixed with the blood, and the circulation of this fluid to every organ and tissue of the system, that each may select from it the very principles which it requires for its growth.
726. Lymphatic absorption commences as soon as nutrition is completed, and conveys the useless, worn-out particles of different tissues back into the circulating fluid; while the respiratory organs and secretory glands perform the work of preparing the waste products to be eliminated from the body. Each of these processes effects a single object, and is performed in a regular manner.
727. "They must succeed each other in proper order in propelling every particle to its proper destination, or life would be sacrificed almost at the moment of its commencement. There is, therefore, a mutual dependence of all portions of the machinery of organic life upon each other, and a necessity for some medium of communication from one organ to another, by which they may convey mutual information of their several conditions, if we may be permitted to employ a figurative expression. Were there no such medium, how would the stomach notify the heart that additional exertion on its part is required, because the stomach is busy in digesting food?
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725. What has been noted in the preceding chapters? 726. Show the manner in which the several processes are performed. 727. How must they succeed each other?
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728. "When we are exerting the muscular system for a long time in some laborious employment, how else are our members to inform the stomach that they are too much occupied with their duties to spare the blood necessary in digestion; that it is requisite that the appetite should decline; and that digestion should cease for the time, even if the stomach should be oppressed with its contents? When we are thinking, how else are the blood-vessels to be told that an unusual supply of their contents is wanting in the head? or when the whole frame is weary with exertion, how, without some regular line of intelligence between all the organs, is the brain to be instructed that circumstances require that it should go to sleep? To supply the necessary medium of communication, Providence has furnished all the animals that possess distinct organs, with a peculiar apparatus called the Nervous System."
ANATOMY OF THE NERVOUS SYSTEM.
729. The NERVOUS SYSTEM consists of the Cer'e-bro-spi'nal Cen'tre, and of numerous rounded and flattened white cords, called nerves, which are connected at one extremity with the cerebro-spinal centre, and at the other, distributed to all the textures of the body. The sympathetic nerve is an exception to this description; for, instead of one, it has many small centres, which are called gan'gli-a, and which communicate very freely with the cerebro-spinal centre, and with its nerves.
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728. What is the medium of communication from one organ to another? 729-754. Give the anatomy of the brain and cranial nerves. 729. Of what does the nervous system consist? What constitutes an exception to this?
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730. The CEREBRO-SPINAL CENTRE consists of two portions: The brain, and the spinal cord. For convenience of description, the nervous system may be divided into the Brain, Cranial Nerves, Spinal Cord, Spinal Nerves, and the Sympathetic Nerve.
731. The term BRAIN designates those parts of the nervous system, exclusive of the nerves themselves, which are contained within the cranium, or skull-bones; they are the Cer'e-brum, Cer-e-bel'lum, and Me-dul'la Ob-lon-ga'ta. These are invested and protected by the membranes of the brain, which are called the Du'ra Ma'ter, A-rach'noid, and Pi'a Ma'ter.
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730. Of what does the cerebro-spinal centre consist? How is the nervous system divided? 731. What does the term brain designate? Name them. How are they protected? Describe fig. 120.
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732. The CEREBRUM IS divided into two hemispheres, by a cleft, or fissure. Into this cleft dips a portion of the dura mater, called the falx cer'e-bri, from its resembling a sickle. The apparent design of this membrane is to relieve the one side from the pressure of the other, when the head is reclining to either side. Upon the superior surface of the cerebrum are seen undulating windings, called con-vo-lu'tions. Upon its inferior, or lower surface, each hemisphere admits of a division into three lobes—the anterior, middle, and posterior. (Fig. 122, 123)
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732. How is the cerebrum divided? What is the use of the falx cerebri? What is seen upon the superior surface of the brain? Its inferior?
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733. When the upper part of the hemispheres is removed horizontally with a sharp knife, a centre of white substance is brought to view. This is surrounded by a border of gray, which follows the depressions of the convolutions, and presents a zigzag outline. The divided surface will be seen studded with numerous small red points, which are produced by the escape of blood from the division of the minute arteries and veins. The gray border is called the cortical, or cineritious portion, while the white central portion is called the medullary. The two hemispheres are connected by a dense layer of transverse fibres, called cor'pus cal-lo'sum.
734. In the interior of the brain there are several cavities, two of which are of considerable size, and are called the lateral ventricles. They extend from the anterior to the posterior part of the brain, and wind their way into other parts of the cerebral organ.
Observation. In the disease called "dropsy of the brain," (hydrocephalus internus,) the serum, or water, is usually deposited in these ventricles. This is effused from the many small blood-vessels of the membrane in these cavities.
735. The brain is of a pulpy character, quite soft in infancy and childhood; but it gradually becomes more and more consistent, and in middle age it assumes the form of determinate structure and arrangement. It is more abundantly supplied with blood than any organ of the system. No lymphatics have been detected, but it is to be presumed that they exist in this organ.
736. The CEREBELLUM is about seven times smaller than the cerebrum. Like that organ, it is composed of white and gray matter, but the gray constitutes the larger portion. Its surface is formed of parallel plates separated by fissures. The white matter is so arranged, that when cut vertically, the appearance of the trunk and branches of a tree (ar'bor vi'tae) is presented. It is situated under the posterior lobe of the cerebrum, from which it is separated by a process of the dura mater, called the ten-to'ri-um. |
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