Read Ebook: Hygienic Physiology : with Special Reference to the Use of Alcoholic Drinks and Narcotics by Steele Joel Dorman

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INTRODUCTION

THE HEAD

THE TRUNK

THE LIMBS

THE HAIR AND THE NAILS

THE TEETH

THE BLOOD

THE HEART

THE ARTERIES

THE VEINS

THE BRAIN

THE SPINAL CORD AND THE NERVES

THE SYMPATHETIC SYSTEM

TOUCH

TASTE

SMELL

HEARING

SIGHT

QUESTIONS FOR CLASS USE

GLOSSARY

INDEX

SUGGESTIONS To Teachers

Seeing is believing--more than that, it is often knowing and remembering. The mere reading of a statement is of little value compared with the observation of a fact. Every opportunity should therefore be taken of exhibiting to the pupil the phenomena described, and thus making them real. A microscope is so essential to the understanding of many subjects, that it is indispensable to the proper teaching of Physiology. A suitable instrument and carefully prepared specimens, showing the structure of the bones, the skin, and the blood of various animals, the pigment cells of the eye, etc., may be obtained at a small cost from any good optician.

On naming the subject of a paragraph, the pupil should be prepared to tell all he knows about it. No failure should discourage the teacher in establishing this mode of study and recitation. A little practice will produce the most satisfactory results. The unexpected question and the apt reply develop a certain sharpness and readiness which are worthy of cultivation. The questions for review, or any others that the wit of the teacher may suggest, can be effectively used to break the monotony of a topical recitation, thereby securing the benefits of both systems.

The pupil should expect to be questioned each day upon any subject passed over during the term, and thus the entire knowledge gained will be within his grasp for instant use. While some are reciting to the teacher, let others write on slates or on the blackboard. At the close of the recitation, let all criticise the ideas, the spelling, the use of capitals, the pronunciation, the grammar, and the mode of expression. Greater accuracy and much collateral drill may thus be secured at little expense of valuable school time.

The Introduction is designed merely to furnish suggestive material for the first lesson, preparatory to beginning the study. Other subjects for consideration may be found in the section on Health and Disease, in the Selected Readings, and among the questions given in the Appendix. Where time will allow, the Selected Readings may profitably be used in connection with the topics to which they relate. Questions upon them are so incorporated with those upon the text proper that they may be employed or not, according to the judgment of the teacher.

NOTE.--Interest in the study of Physiology will be much increased by the use of the microscope and prepared slides. These may be obtained from any good optician.

INTRODUCTION.

Physiological study in youth is of inestimable value. Precious lives are frequently lost through ignorance. Thousands squander in early years the strength which should have been kept for the work of real life. Habits are often formed in youth which entail weakness and poverty upon manhood, and are a cause of lifelong regret. The use of a strained limb may permanently damage it. Some silly feat of strength may produce an irreparable injury. A thoughtless hour of reading by twilight may impair the sight for life. A terrible accident may happen, and a dear friend perish before our eyes, while we stand by powerless to render the assistance we could so easily give did we "only know what to do." The thousand little hints which may save or lengthen life, may repel or abate disease, and the simple laws which regulate our bodily vigor, should be so familiar that we may be quick to apply them in an emergency. The preservation of health is easier than the cure of disease. Childhood can not afford to wait for the lesson of experience which is learned only when the penalty of violated law has been already incurred, and health irrevocably lost.

NATURE'S LAWS INVIOLABLE.--In infancy, we learn how terribly Nature punishes a violation of certain laws, and how promptly she applies the penalty. We soon find out the peril of fire, falls, edged tools, and the like. We fail, however, to notice the equally sharp and certain punishments which bad habits entail. We are quick to feel the need of food, but not so ready to perceive the danger of an excess. A lack of air drives us at once to secure a supply; foul air is as fatal, but it gives us no warning.

Nature provides a little training for us at the outset of life, but leaves the most for us to learn by bitter experience. So in youth we throw away our strength as if it were a burden of which we desire to be rid. We eat anything, and at any time; do anything we please, and sit up any number of nights with little or no sleep. Because we feel only a momentary discomfort from these physical sins, we fondly imagine when that is gone we are all right again. Our drafts upon our constitution are promptly paid, and we expect this will always be the case; but some day they will come back to us, protested; Nature will refuse to meet our demands, and we shall find ourselves physical bankrupts.

We are furnished in the beginning with a certain vital force upon which we may draw. We can be spendthrifts and waste it in youth, or be wise and so husband it till manhood. Our shortcomings are all charged against this stock. Nature's memory never fails; she keeps her account with perfect exactness. Every physical sin subtracts from the sum and strength of our years. We may cure a disease, but it never leaves us as it found us. We may heal a wound, but the scar still shows. We reap as we sow, and we may either gather in the thorns, one by one, to torment and destroy, or we may rejoice in the happy harvest of a hale old age.

THE SKELETON.

"Not in the World of Light alone, Where God has built His blazing throne, Nor yet alone on earth below, With belted seas that come and go, And endless isles of sunlit green Is all thy Maker's glory seen-- Look in upon thy wondrous frame, Eternal wisdom still the same!"

HOLMES.

ANALYSIS OF THE SKELETON.

NOTE.--The following Table of 206 bones is exclusive of the 8 sesamoid bones which occur in pairs at the roots of the thumb and great toe, making 214 as given by Leidy and Draper. Gray omits the bones of the ear, and names 200 as the total number.

THE SKELETON, or framework of the "House we live in," is composed of about 200 bones.

USES AND FORMS OF THE BONES.--They have three principal uses: 1. To protect the delicate organs; 2. To serve as levers on which the muscles may act to produce motion; and 3. To preserve the shape of the body.

Bones differ in form according to the uses they subserve. For convenience in walking, some are long; for strength and compactness, some are short and thick; for covering a cavity, some are flat; and for special purposes, some are irregular. The general form is such as to combine strength and lightness. For example, all the long bones of the limbs are round and hollow, thus giving with the same weight a greater strength, and also a larger surface for the attachment of the muscles.

If the bone be burned in the fire, thus consuming the animal matter, the shape will still be the same, but it will have lost its tenacity, and the beautiful, pure-white residue may be crumbled into powder with the fingers.

FIG. 2.

We thus see that a bone receives hardness and rigidity from its mineral, and tenacity and elasticity from its animal matter.

FIG. 3.

THE STRUCTURE OF THE BONES--When a bone is sawed lengthwise, it is found to be a compact shell filled with a spongy substance This filling increases in quantity, and becomes more porous at the ends of the bone, thus giving greater size to form a strong joint, while the solid portion increases near the middle, where strength alone is needed. Each fiber of this bulky material diminishes the shock of a sudden blow, and also acts as a beam to brace the exterior wall. The recumbent position of the alligator protects him from falls, and therefore his bones contain very little spongy substance.

REPAIR OF THE BONES.--When a bone is broken, the blood at once oozes out of the fractured ends. This soon gives place to a watery fluid, which in a fortnight thickens to a gristly substance, strong enough to hold them in place. Bone matter is then slowly deposited, which in five or six weeks will unite the broken parts. Nature, at first, apparently endeavors to remedy the weakness of the material by excess in the quantity, and so the new portion is larger than the old. But the extra matter will be gradually absorbed, sometimes so perfectly as to leave no trace of the injury.

A broken limb should be held in place by splints, or a plaster cast, to enable this process to go on uninterruptedly, and also lest a sudden jar might rupture the partially mended break. For a long time, the new portion consists largely of animal matter, and so is tender and pliable. The utmost care is therefore necessary to prevent a malformation.

The bones which form the joint are tied with stout ligaments , or bands, of a smooth, silvery white tissue, so strong that the bones are sometimes broken without injuring the fastenings.

THE BONES OF THE SKULL AND THE FACE form a cavity for the protection of the brain and the four organs of sense, viz.: sight, smell, taste, and hearing. All these bones are immovable except the lower jaw, which is hinged at the back so as to allow for the opening and shutting of the mouth.

THE SKULL is composed, in general, of two compact plates, with a spongy layer between. These are in several pieces, the outer ones being joined by notched edges, sutures , in the way carpenters term dovetailing.

FIG. 4.

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