The Essentials of anatomy, physiology, and hygiene: a text-book for schools and academies

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Preface

It has been my aim in preparing this volume to compress within the narrowest space such a clear and intelligible account of the structures, activities, and care of the human system as is essential for the purposes of general education. I have also sought to present the facts and principles of the subject in such a natural order as will best subserve the true ends of scientific education. Useful books of information upon physiology are already numerous, but they are too generally deficient in making the science valuable as a means of mental training. Of course, the great object of physiology is to teach how to preserve health, but this is not best done by merely memorizing rules. The rules must be supported by reasons, and if there is not some thorough understanding of the mechanism and powers of the human body, such as will task the efforts of the student, the real fruits of knowledge will not be gained. I have accordingly given prominence to the anatomical and physiological facts which are necessary preliminaries to instruction in hygiene, and in the reasonings upon these facts I have aimed to attract and interest the pupil, to teach him something of the scientific methods of approaching the

Vi PREFACE.

subject, and to connect new acquisitions logically

with those already gained, so that the knowledge of the subject may become, as it were, organized into faculty in the minds of the students. So important has it seemed to me to impress deeply upon the pupil's mind the laws of connection and dependence among the various parts of the living system that I have thought it best to present this view, in outline, at the very outset, I have, therefore, prefixed to the volume a General Analysis, which, while it serves as a table of contents, is interspersed with running comments explaining the general relations of the different organs and processes, and I recommend that this analysis be carefully read by the pupil, so that he may become familiar with its argument liefore proceeding to the detailed study of the text.

One of the greatest modem reforms in scientific study is undoubtedly that which makes it more and more objective, so that the student shall constantly confirm the knowledge he gets from the book by reference, as far as possible, to the objects themselves, making his acquaintance with them direct, and his information real. The various sciences lend themselves to this mode of study in different degrees; chemistry and physics favoring experiment, and botany offering systematic observation more than any other scientific subjects. Physiology is less favorable to the objective method. For the purpose of ordinary education, it must be chiefly taught from the book, with such accompaniments of lectures and illustrations by charts as the circumstances will allow. But even here much may be done to give the pupil more correct ideas of the

L

PREFACE. vil

elements of the subject than can be obtained from the book alone. A good manikin is an invaluable help to the popular study of anatomy and physiology. Human dissection being out of the question, the manikin, which can be taken to pieces so as to show all the organs in their situations, connections, and relative dimensions, will afford the pupil a vivid and exact conception of the dependent parts of the living body, and make his physiological knowledge truthful and actual. A manikin for school pur. poses costs about $250, and may be imported from Paris,* where they are made, free of duty for educational institutions.

A great deal is also to be learned from such rough dissections of organic tissue and structures as may be made anywhere. Every butcher's shop is full of specimens of all parts of animals, that can be cheaply obtained for examination, and parents and teachers should encourage pupils to make such rude dissections as are practicable, and will help to give correct ideas of the relations and functions of the different organs.

The study of the minuter parts of organized beings with the microscope, histology as it is called, has come into great prominence in modern times, and may be said to have revolutionized the science of hfe. No class in physiology should be without a microscope for the direct study of cell-structures and the finer tissues of both plants and animals. A suitable instrument, with a magnifying power of three hundred and fifty diameters, will show the circulation in the web of a frog's foot, and open a new world of fascinating and wonderful observation, 'Auioux ii the principal manufacturer of these models.

viii PREFACE.

while it may be bought for sixteen dollars. Microscopic preparations of blood-corpuscles, muscular and nervous tissues, and sections of organs may be got for about twenty cents apiece, but it is desirable that the pupil should not rely upon these, but should learn the method of preparing and mounting objects himself. The microscope is not to be recommended as a mere toy to amuse idle curiosity ; there is work connected with it which is in a high degree educational. It cultivates critical observation and careful lanipulation, and is invaluable as a means of selfeducation. The little hand-book of Phin * will be found useful in guiding beginners with this instrument .

The illustrations are largely copied from Gray's " Anatomy," though I am also indebted to Dalton*s " Physiology," to Flint's " Physiology," to Ranney*s "Applied Anatomy of the Nervous System," to Riidinger's " Topographisch-Chirurgische Anatomic," and to Neumann's " Hand-Book of Skin Diseases." Many of the figures I have altered to suit my purpose, and the necessary descriptions are so inscribed upon or near them as to do away with the inconvenience of lettered references. A few of the cuts are original.

For the use of material other than the illustra* tions, I have to acknowledge my indebtedness to Flint, Beaumont, Strieker, Neumann, Riidinger, Paget, Maudsley, Reynolds, Aitken, Huxley, Soelberg Wells, Uhle and Wagner, Foster, and especially to Dalton.

R. S. T.

March i, 1884. * "A Book for B^inners with the Microscope," 30 cents.

GENERAL ANALYSIS.

Part I.— Introduction

Gives certain necessary definitions, and describes the cell and its properties as being the real basis of all more fully developed living organisms.

CBAFTBR PAGB

I Definitions x

II. Minute Structure of the Body 3

Part II. — Organs of Motion

A lai^ body entirely composed of cells would be a soft, jelly-like mass, incapable of locomotion or of self -protection. But to obtain food it must be able to move from place to place, and also to move its different parts with reference to one another. For these purposes there must be points of resistance and points of support. These points are furnished by the bones, which act as levers, the joints being the fulcra.

I. Bones in General 9

II. Particular Bones. — ^Joints 15

III. Injuries of Bones and Joints 25

But levers alone are of no use. The bones form a strong framework for the body, but they can not move themselves. To produce motion, organs are required, which can become longer or shorter, under varying circumstances. Such organs are the muscles.

IV. Muscles • • • . • 99

GENERAL ANALYSIS.

Part III.— Organs of Repair

Energy is never lost or created. If the body loses energy in one way, it must gain it in another, or it will soon be worn out. Every muscular contraction wastes a certain amount of material, and an equal amount must be again supplied. This is done in the form of food.

CHAPTBR PAGB

I. Food. — Supply and Waste 42

But food, as it eidsts outside of the body, can not be appropriated by the wasting tissues. It must first be prepared. The process of preparation is cafled digestion.

II. Mastication. — Swallowing 50

III. Stomach-Digestion 57

IV. Intestinal Digestion 79

After the food has been so far prepared, it must in some way be carried through the body to all its different parts, that each may take what it requires for its sustenance. This is accomplished by means of a fluid which passes continually and rapidly through all parts of the body, carrying the nutritious material. This fluid is the blood.

V. The Blood 93

But the blood, besides carrying nutriment, must also remove the waste and used-up matters, which injure the health if they remain in the body. There is also a gas, called oxygen, which is found to be necessary to the processes of nutrition. This gas exists in the air, and is taken from the air into the blood. The process, by which the blood gets rid of impurities and takes in oxygen, is called respiration.

VI. Respiration 99

VII. Asphyxia 120

The blood can not visit the different parts of the body of its own accord. It is a fluid, and must be propelled. There are organs for this purpose, which keep up what is called the circulation of the blood.

VIII. The Heart 125

IX. The Blood-vessels 236

X. Disorders of Circulation. — HiEMORRHAGX . , 150

GENERAL ANALYSIS. xi

Part IV.— Organs of Co-ordination

The motions of the body, the continual waste and supply, and the processes of digestion and circulation, form a very complicated series of phenomena. Certain parts of the body require more blood at certain times than at others. Processes taking place at the same time in different parts of the body might conflict and interfere with each other. We find, therefore, a system of organs whose function it is to harmonize or co-ordinate all these processes, to produce a sympathy between them, and make them all work together for the common interest. This is the nervous system.

CHAPTER PAGE

I. Nerve-Substance 164

II. The Sympathetic System 174

III. The Spinal Cord 183

IV. The Brain 194

V. Special Nerves. — Hygiene 208

Part V. — Organs of Protection

All the organs previously described form a very delicate structure, which is continually exposed to external injurious influences. It is exposed to heat and cold, to blows and scratches, and all manner of violence, and so we find it enwrapped in a strong covering, which protects it from these influences, partly by its own strength and toughness, and partly by certain organs which are imbedded in it, and form a part of it. This organ is the skin, with the various glands and other structures found therein.

I. The Skin 217

II. Functions and Care of the Skin . . . .223

Part VI.— Organs of Perception

The body being now complete, so far as its movements, nutrition, co-ordination of parts, and protection are concerned, we see that, as its food must come from outside, there must be organs to bring it into relation with the external world, to aid it in its search for food, and to protect it during the search. These organs are the organs of the senses, which bring us into relation with what is outside of us, and in this way are the sources of our ideas. The elementary one of these senses is touch, the others being only modifications of it.

xii GENERAL ANALYSIS.

CHAPTER PAGE

I. Touch, Taste, Smell . 237

II. Hearing 246

III. Sight 254

Part VII. — Organ of Communication . . . .272

The body beings now practically complete, we find still another organ, whose function it is to enable us to communicate our ideas to others. This organ is the larynx, the organ of speech, that wonderful faculty which has had so much to do with creating the tremendous gap that exists between man and the lower animals.

Part VIIL— Stimulants and Narcotics . . .277

The body being thus fitted by its structure to maintain its integrity amid natural surroundings, is often subjected to artificial conditions, which tend to cause disease and shorten life. In illustration of this may be dted the wide-spread use of stimulants and narcotics.

Index 337

Chapter I. Definitions

I. Definitions. — The science which tells us about the different parts of the body, what they are, where they are, and how they look, is called anatomy.

The science which tells us about the purpose of these parts, what they do and how they do it, is called physiology.

The science which tells us what will interfere with the working of these parts, what will injure and what will help them, and how to avoid what is hurtful, is called hygiene,

A part of the body, which is so small that when it has been separated from other parts it can not be further subdivided without the destruction of its organization, is called an anatomical element^ as a cell or a fiber.

Two or more anatomical elements, united or interwoven so as to form one substance, make what is called tissue ; e. g., fatty tissue, connective tissue, etc.

A part of the body, which is made up of anatomical elements and tissues, together forming otve

2 INTRODUCTION.

whole, which can be separated from the rest of the body as an entire mass, and which performs a particular function, is called an organ; as, the liver, the heart, a bone, or a muscle.

A number of organs, similar in structure, but differing in size and shape, and spread throughout the body, are called a syste^n ; as, the nervous system, the arterial system, etc.

Several organs, which differ in structure but are so connected as to work together for a particular end, are called an apparatus ; thus, the stomach, liver, etc., constitute together the digestive apparatus.

The work that is done by a healthy organ in the body is called its function ; e. g., the secretion of bile is a function of the liver.

MINUTE STRUCTURE OF THE BODY.

2. Minute Structure of the Body.— The body, when its parts are examined with the microscope, is found to be made up mainly of cells, fibers, anAfiuids. The cell is considered to be the original element out of which every other element in the body is formed ; fibers, fluids, etc., being derived from or generated by previously existing cells.

The different consistency of different organs is due to the varying proportions of these elements. If the fibers are in the largest proportion, the tissue or organ will be hard, tough, and elastic ; if the cells form the greatest part, it will be soft, inelastic, arid yielding.

3. The Fiber. — Tht; fiber proper (Fig. 1) is a slender thread, composed of a hard whitish or yellowish substance, sometimes elastic and some- fig. i.— Fibrous tissue, times not, but very tough

and strong. Fibers are found in almost all parts of the body, binding the parts of organs together, and

4 INTRODUCTION.

constituting almost the entire mass of some parts, as the tendons or sinews, for instance. The word " fiber ** is also used of certain portions of muscular and nervous tissue, in a different sense from the one given above. These differences will be explained hereafter.

4. The Cell. — The cell is the most important structure in the living body, whether animal or vegetable. Life resides in the cell ; and every plant or animal may really be looked upon as a mass composed of billions of cells, each of which is alive, and each of which has its own part to play in the nourishment of itself and the rest of the body.

A single cell * (Figs. 2 and 3) is a portion of al-

Fio. 2, — Epithelium from the mouth.

Fio, 3. — Liver-cells.

buminous matter, which has by some been called protoplasm,! sometimes surrounded by a thin mem-

* Scrape gently the surface of the tongue, and put the fluid thus obtained under the microscope. Plenty of cells will then be seen, similar in appearance to those shown in Fig. 2.

f Pr6' toplasm, from two Greek words, signifying the first (or primitiye) formed matter, because, so far as we know at present, it is the

F

MINUTE STRUCTURE OF THE BODY.

brane and sometimes not, and usually having in its interior what looks like a smaller cell. This small body is called the nii'cleus of the larger one. Inside of the nucleus is often found another exceedingly minute body, or sometimes a mere shining point, called the nucle'olus (see Fig. 52).

5. Protoplasm. — The protoplasm, or matter which forms the mass of a cell, is of a semi-fluid consistency, somewhat like jelly, and can not be distinguished by chemical tests from albumen. Hence it is said to be albuminous in its nature, resembling to some extent the white of a raw egg, which is almost pure albumen. All cells are so exceedingly small, being rarely more than -j-tfijnr of an inch in diameter, that we really know very little of their minute structure, on account of. the difficulty of investigating them with such imperfect instruments as we have.

6. Granular Matter. — The points just mentioned are the most characteristic of the cell. Besides the cells, fibers, and fluids, there is a great deal of matter in different parts of the body, which has been formed or deposited by the cells at different periods of their growth. This matter, under the microscope, sometimes appears granular, or as if made up of very minute specks, and sometimes almost transparent. Some of it is found to be fat in a finely-divided state, but some of it is albuminous, and some of it contains mineral matter in considerable amount.

7. Difference between Living and Dead Cells. — K living and a dead cell look precisely alike, exceptsEmplest fonn of living mailer, and makes up (he only part of all animal and vegetable bodies which shows signs of life.

6 INTRODUCTION.

ing that the dead one is motionless, A living cell, minute as it is, frequently possesses the power of independent motion, or at least is able to change its form (Fig, 4). It also can take up nourishment into its mass, and can propagate itself. The movements of the cell can be beautifully seen in the white cells of the blood, which will be described hereafter.

8. Growth of Cells.— A cell propagates itself in several ways ; one of the most common is by dividing into two parts. This operation has been often watched under the microscope by skilled observers. The change is seen to begin in the nucleus, and, as that divides by a line through its center, the protoplasm of the cell arranges itself in halves around each part of the nucleus, its surface dipping in toward the center, until finally the approaching surfaces meet and the

Fib. s,— Cell dividing and (c

cell is divided into two new cells, each with its nucleus, and in every way complete (Fig. 5). This division goes on with great rapidity. The secretion from the throat and nose in nasal catarrh is composed mainly of cells, which are thrown off by millions during an inflammation.

MINUTE STRUCTURE OF THE BODY j

9. Other Properties of Cells. — Cells also possess other powers which enable them to perform their important offices in the body. They are able to select certain substances out of a general mixture, and reject others. This is done by the liver-cells, for example, which secrete the bile, and by the cells of those glands which secrete the saliva. The cells of the brain act, in some unexplained way, as the instruments of thought. The cells in the kidneys separate matters from the blood which are very poisonous, and have to be expelled from the system.

The powei of division and of numerical increase of cells is not unlimited. If a portion of the body is wounded, it is healed again by the active efforts of the uninjured cells in the borders of the wound. The action of these cells ceases, however (if the part is healthy), to reproduce substance, when the part made vacant by the injury has been filled up. Why does this action of the cells, once started, not continue until the body dies ? Why does the replacement of tissue cease as soon as the former surface is reached ? This question can not at present be answered.*

Thus we see that the cell, minute as it is and simple as it is, performs its office in the body with

* When the cells in the borders of a wound or sore are not in a healthy condition, they sometimes increase in number very rapidly, but the new cells, instead of being like the older ones, are larger, chiefly owing to the greater amount of fluid in their interior. This makes them soft and spongy, and seems to interfere with their functions. They do not nourish themselves properly, and they increase and grow beyond the limit where they should stop, and where, if they were healthy, they would stop. This unhealthy growth is what is known 9& proud fleshy and it has to be repressed by proper surgical treatment.

8 INTRODUCTION.

care and evidence of forethought and intention. It does what is necessary and no more. It does not act blindly. It does all it does with a purpose. Where and what is the intelligence that directs the active living cell to repair so far and no farther, to eat this and reject that, to multiply up to a certain point and then stop, and, most wonderful of all, to take upon itself the duties of other cells when they are sick and unable to act,^ and stop performing these extra duties, when the other cells recover ?

* When the kidneys, for instance, are diseased, so that the excretion of urine is interfered with, it is found that some of the poisonous matters which usually pass out through them are ejected from the body through the lungs and skin. In such cases, physicians try to assist this process by inducing active perspiration, so as to relieve the kidneys from work as much as possible, and allow them to rest until they get welL

Part II. Organs Of Motiont

CHAPTER I.

BONES. — GENERAL STRUCTURE.

10. Uses of the Bones. — If the body were com. posed merely of cells, such as have been described, with fibers and fluids, it would be a shapeless, jelly-like mass, incapable of locomotion, and of self-protection. There is a necessity, in such a large mass, of points of support and resistance, and the organs or tissues which furnish such points must be tough, hard, and elastic. Such organs are the bones, which form the framework of the body and determine its shape and size. Their most important offices are two in number, viz., to act as levers and points of support and action for the muscular parts, and to protect the soft and delicate organs from external injury.

11. Living and Dead Bone. — A bone, as we usually see it outside the body, is as different from a living bone as the skin of a corpse is from the living skin. We usually see it deprived of blood, while in the living body it is full of it, and is of a pinkish-white color externally, and deep red within.

12. Composition of Bone. — To accomplish the lO ORGANS OF MOTION.

two purposes above mentioned, bones must be hard and tough, in order to maintain their stiffness when the muscles pull upon them, and also to be able to resist external blows. They must also be in some degree elastic, or they would be too brittle for use, and would snap in two under great pressure. Accordingly, we find all bones composed of two kinds of material, so thoroughly mingled and united that, when either kind is removed, the bone still retains its peculiar shape and size, although of course it does not weigh as much as before* About two thirds of the weight of every bone in the adult consists of earthy substances, mostly lime phosphate and lime carbonate, and the remaining third of animal matter, part of which can be separated from the rest of the bone by long boiling, and is known as gelatine.

If a bone be burned in a hot fire, all of the animal matter will be destroyed, and the earthy matters left. These will still retain the shape of the bone, but will be white in color, and will easily break and crumble in the fingers. If a bone, on the other hand, be soaked for a time in dilute hydrochloric acid, all the earthy matter will be dissolved out, and the animal portion left. This, as in the other case, will retain the shape of the bone, but will be flexible and tough, and may even be tied in a knot.

By the combination of these two kinds of matter, then, the bone is made hard, tough, and elastic, and admirably adapted to its uses in the body.

13. The Composition of Bone varies with Age. — In infants and children, the amount of animal matter in the bones is proportionately greater than in

BONES.— GENERAL STRUCTURE. \\

the adult, and so the bones of very young people will often bend when injured, instead of breaking. Surgeons call this the " green-stick " fracture, because the bone is bent like a green twig, only a small portion of it on the outside of the bend being broken or torn apart. As a person grows older, the amount of earthy matter increases, until in old people the bones become very brittle, and break with very shght blows.

14. Varieties of Bone and their Structure. — Bones are divided, according to their shape, into long bones, short bones, flat bones, and a fourth kind, called irregular, which combine qualities belonging to the other classes. The long bones are found only in the limbs, and are the most important to the surgeon, as it is in them that most fractures and other injuries occur. They are divided into a shaft and extremities. The shaft of every long bone consists of hard, compact, closely-grained tissue, somewhat like ivory. This is the only part used in the manufacture of ornaments, buttons, knife-handles, etc. The extremities of these bones form the joints, and, in order to give greater security and a greater purchase to the muscles as well as a greater surface for their attachment, the ends are much larger than the shaft. The tissue of which they are composed is also not so hard and close in texture, as, if it were so, the bone would be too heavy. There is no finer example of economv of material and the combina tion of strength with lightness than the structure of the long bones (Fig. 6). The ends are made of fine threads of bone interlaced and crossing and eupporting each other, so as to make a sort of spongy tissue, full of httle cavities, and yet very strong and

ORGANS OF MOTION.

tough. And even the shaft of the bone is not solid, but, as every one knows, is hollow in the middle. This hollow space and the little cavities of the ends of the bone are filled with what is called ^marrow, a substance composed chiefly of blood-vessels and fat, which has important duties to perform in the growth and nourishment of the bone. The other varieties of bone are composed entirely of the spongy (or cancellous) tissue, with a thin layer of hard, compact tissue on the surface.

15. The Periosteum and the Minute Structure of Bone. — AH the bones are covered with a very tough, strong, fibrous membrane, called \he perios'teum, excepting at the parts which enter into the formation of the joints, where they are covered with cartilage. This membrane adheres so closely to the bone as to require considerable force for bony fibers ai the upper its Separation. It seems to form

- ing somewhat eiaEger- . j ^l c

ated so as to make H pcHosteum and the marrow 01

more plain. the bones are necessary to their

growth and nourishment. The

blood-vessels and nerves spread and divide in these

tissues before entering the actual substance of the

bone. The bone itself is full of minute channels and

Fio. 6.— The right femur, or thigh-bone, sawn in two lenglhwiBe. Notice the arrangement r

SONES.— GENERAL STRUCTURE.

tubes varying in size from ^j^ to the yj-J-mr of an inch in diameter, through which the blood cir. culates, and the smallest of these tubes are connected at one end with exceedingly minute cavities in the bone, in each of which lies a httle cell, which does the work of nourishing, repairing, and enlarging the bone (Fig. 7). Thus we see that, even in so hard and firm a tissue as bone, what has been said about cells holds true.

They are the real life of the bone ; the J i^eparate from the blood the necessary material and deposit it around themselves, somewhat as a crab renews his shell every year after getting rid of the old one. 16. Uses of the Periosteum. — It has long been known that, when the periosteum is severely bruised and separated from the bone by violence, the portion of bone deprived of the periosteum dies and has to be removed from the body. It is also found * that a portion of bone, or even an entire bone, may be removed from the body, and if it be carefully done, so as to leave the periosteum in its place, the bone will grow again. A remarkable example of

The small black spots sit

which the bone-celis live. The fi

are canals through which the plas

tioa 12a) of the blood passes. The lai^

holes are for blood-vessels.

this was a case operated upon by the late Dr. James R. Wood, of New York. In a young woman, whose lower jawbone had become dead and caused her great suffering, this distinguished surgeon removed the whole jaw, leaving the periosteum and even the teeth, held in their places by an apparatus made for the purpose. The entire bone grew again, and the teeth became fixed in it as it grew. The person died several years afterward, and her skull, showing the result of this wonderful operation, is in the museum at Bellevue Hospital.*