An academic physiology and hygiene ...

Front matter

Chap*-™„_ Copyright No.

Shelf. lB_S 5"

UNITED STATES OF AMERICA.

Preface

In the preparation of this volume an endeavor has been made to keep steadily in view the fact that the study of the structure and functions of the body and of its various organs should conduce to an intelligent conception of the normal conditions and processes through which health and life are maintained. Anatomy and Physiology, while not being unnecessarily neglected, have been treated as a means rather than as an end.

In early eras of thought, bodily disorder and disease were regarded as the gifts of the gods, and as marking their judgments ; and the task of preventing plagues, fevers, and the mysterious diseases of brain and mind, was esteemed as hopeless and impracticable. But in course of time the lessons taught by bitter experience and the progress of modern civilization began to exercise a distinct influence upon public health. The knowledge possessed by the few was sought by the many ; and the domains of the theologian and the scientist began to be invaded in the search for light on all subjects pertaining to moral, mental, and physical well-being. The sources and causes of disease began to be tolerably well understood, and it became known that man possesses the power of preventing many of the ailments which shorten life and decimate the population of communities and nations.

VI PREFACE.

Hygiene founds its lessons to the individual upon the same basis as those which it inculcates on the masses. There are so many conditions over which an individual has control, that it is impossible to determine which is absolutely of the greatest importance. It may be safely said that one must first possess the intelligent conception of the normal conditions of structures and processes to which we have referred, and then must become acquainted with the nature, quantity, and proper preparation of foods, and the conditions essential to their healthy digestion ; the composition of the beverages which he imbibes, their values, and their effects on the organism ; the composition of air, the causes affecting its purity, and the means of securing its change and renewal when vitiated ; the relations of proper bathing, cleanliness, and clothing to health must be understood ; the part played by exercise, rest, and recreation in maintaining physical and mental vigor must be known ; the dangers attending the accumulation of refuse matters in the vicinity of human habitations must be appreciated, and the means of effectively disposing of them should be known ; and finally, the individual should acquire knowledge that will enable him to render intelligent assistance, and often save life, in emergencies. The development of public interest in all matters relating to sanitary science renders needless an apology for adding special chapters on the foregoing topics.

While the treatment of each topic is elementary, and divested of technicality as far as practicable, the essential facts are stated with the fulness needed to set forth clearly their educational value. The authors have brought to bear special knowledge of the subjects on which they have written, together with practical experience in teach-

PREFACE. Vll

ing them. In addition, the standard works of Dalton, Carpenter, Huxley, the manuals of health-science of Wilson, the American Health Manuals, etc., and the writings of many other eminent scientists, have been consulted, and most valuable assistance derived from their teachings.

In conclusion, the authors trust that this volume will possess attractions, and attain a popularity and usefulness, equal to those of the other works of the series which it is intended to complete and crown.

O. M. B.

February, i8q-?.

Contents

I. — Introductory. — Knowledge of the Body. — Divisions of the Subject. — Anatomy, Physiology, and Hygiene and their Relations. — Composition of the Body. — Cell Structure. — The Tissues. — The Fluids. — Organs and Systems. — Public Hygiene and Personal Hygiene I

THE OSSEOUS SYSTEM, OR SKELETON.

II. — Composition and Structure of Bone. — Composition of Bone. — Structure of Bone. — The Cartilages. — Classes of Bones. — Growth and Development. — Repair when Fractured . . . . . . . . . . .11

Chapter I. Introductory

1. Knowledge of the Body. — The investigations and experiments made by some of the most profound thinkers of all countries and ages have been employed in the discovery of the structure and functions of the human body. This continued study and research has not been inspired by mere idle curiosity and for its gratification. The preservation of health, and the desire for long life, as a sequence, have stimulated inquiry into all that continued to remain unknown of the structure of the body, of the offices and actions of its various organs, of the relations of each organ and set of organs to all others, and of the conditions necessary to the healthy and harmonious activity of the whole organism.

2. Having a knowledge of only the general outlines of the structure of the body and of its various functions, all can understand important hygienic laws, the proper observance of which tends to insure health, long life, and happiness. It is of but little use to know how our bodies are constructed and what functions are performed by their organs, unless we utilize such knowledge in the prevention of disease and the preservation of life. When we know just what results will follow the violation of each law of existence, we become measurably the arbiters of our own health ; and our enlightened judgment stands as a guard over our lives, possibly preventing the first step toward disease.

3. Divisions of the Subject of Study. — The sciences which treat of the structure, functions, and preservation of health of the body, are Anatomy, Physiology, and Hygiene.

4. Anatomy (Gr. ana, up ; and temnein, to cut) is the science which describes the structure, situation, and relation of the different parts of the body. A knowledge of this comes only from a minute examination of all the parts that constitute the structure, and has been obtained through microscopic examinations and by dissections of lifeless bodies.

5. Through continued investigation and experiment the amount of knowledge has been enormously increased, and that which was already possessed has been rendered much more accurate. Surgical skill has kept pace with this progress in many directions previously unthought of. Operations that were formerly regarded as quite certainly fatal to life, are now relieved, to a great extent, of their dangers and terrors. The steady, onward progress of scientific knowledge enables the surgeon to relieve diseased conditions by means of operations that would, in former times, have been ascribed to the agency of the " black art."

6. Physiology (Gr. phusis, nature, and logos, discourse) is the science which describes the functions of organs and sets of organs, or the mode in which they operate. Physiological knowledge comes, in part, from experiment

INTRODUCTORY. 3

and the study of structures, and largely from experience and observation. Experiments made upon the lower animals have added greatly to our knowledge of physiological processes.

7. According as it treats of one or other of the two great groups of organic beings, it is either animal physiology, or vegetable pliysiology. Human physiology is, of course, restricted to the human body.

8. Hygiene (Gr. hygeia, health) is the science, practical hygiene the art, of preserving health. While it is the province of medical science to treat disease when it actually appears, it is that of hygiene to enable us so to place ourselves in relation to our surroundings, and so to regulate our lives, that disease may be warded off. Medicine deals with cure, hygiene with prevention ; and prevention is better than cure.

9. The science of health preservation is wide in its scope, embracing as it does inquiries into nearly all other sciences. It calls upon chemistry to contribute information concerning the composition of foods, the nature of the impurities of air, and the contaminations of water-supply. It appeals to physics to explain the diffusion of gases, — how noxious gases from sewers gain access to our dwellings, and calls upon it for contrivances to abate the evil ; again it calls upon this science to explain methods of securing proper ventilation of our abodes. It demands of botany and zoology descriptions of the minute parasites that sometimes infest foods and render them unwholesome. Of geology it inquires the nature of the strata from which supplies of water are obtained ; and from physiology it learns the conditions which should prevail in healthy action of the body.

10. Composition of the Body. — There are sixty-four substances which are known as simple substances, or elements ; and they are so regarded because they cannot be decomposed and resolved into simpler constituents. All animal, vegetable, and mineral bodies are formed by a union of various numbers of these elementary substances in different proportions and ways.

11. Chemistry has demonstrated that the human body contains fourteen elementary substances, viz., oxygen, hydrogen, nitrogen, carbon, phosphorus, calcium, fluorine, sulphur, chlorine, sodium, iron, potassium, magnesium, and silicon. In the bodily structures these elements do not exist in simple form, but are so combined as to form chemical compounds called proximate principles.

12. The proximate principles, or compound substances constituting the body, are of three classes, viz., those derived from the mineral or inorganic world, as water, chloride of lime, phosphate of lime, phosphate of soda, chloride of sodium (common salt), and other salts ; the carbonaceous compounds, as starches, sugars, and oils ; and the nitrogenous compounds, as albumen, fibrine, etc. These exist in a healthy human body weighing 154 pounds in about the following proportions : Water, a compound of oxygen and hydrogen, 1 1 1 lbs. ; gelatine, composed of carbon, hydrogen, oxygen, and sulphur, 15 lbs. ;fat, 12 lbs. ; phosphate of lime, forming the principal part of the earthy matter of the bones, 5 lbs. 13 oz. ; carbonate of lime, also entering into the composition of bone, 1 lb. ; albumen, found in the blood, brain, and almost all the other organs, 4 lbs. 3 oz. ; fifo'ine, forming the clot of the blood, and found in the muscles, about 4J lbs. ; calcium found in the bones, 3 oz. ; phosphate of soda, found in the brain and all

INTRODUCTORY. 5

other nervous tissue, 400 grs. ; phosphate of potash, also found in the brain and nerves, 100 grs. ; phosphate of magnesia, found in the bones, 75 grs. ; chloride of sodium, 376 grs. ; sulpJiate of soda, found in the blood, more than 1 oz. ; carbonate of soda, in the blood and bones, about 1 oz. ; sulphate of potash, about 1 oz. ; peroxide of iron, in the blood and elsewhere, more than 9 oz. ; and silica, a very small quantity.

13. These substances and their proportions are not given here as necessary for memorization, but in order that the diversified nature of the composition of the body may be impressed. They are constantly undergoing change, being transformed into waste or effete products, which are discharged from the body. This change is necessary to life ; and in order to compensate for the waste occasioned by this constant destruction, new material must be regularly supplied. All the elements necessary for the maintenance of the composition of the body are derived from proper food, and are held in solution in the blood which distributes them to the various structures.

14. Food is taken into the body in obedience to a want made known by the sensation of hunger when it relates to solid or semi-solid matters, and by thirst when the want relates to water.

15. Cell Structure. — The microscope shows that animal as well as vegetable structures are composed of cells (Lat. cella, a store-room). A cell is a minute, membranous sac enclosing a more or less fluid mass of matter. In this substance, in most cells, are found one or more spots or nodules of condensed matter called nuclei (Lat. nucleus t a nut or kernel). These nuclei first exist in a transparent, structureless mass called protoplasm.

In the course of development, this matter breaks up into microscopic globules, each enclosing a nucleus ; and thus the cells are formed and multiply.

16. The Tissues of the Body. — The word tissue means, literally, a woven structure. Variously modified in form and nature, the interwoven, grouped, or united cells form different tissues or solid portions of the body.

17. The tissues have been classified and named as follows : Epithelial tissue includes the skin and delicate lining membranes of the cavities of the body, the hair, and the nails of the fingers and toes ; muscular tissue, the contractile tissue of which all the muscles are examples; adipose tissue, composed of fat cells and enclosed fat ; cartilaginous tissue, commonly called " gristle," forms the surfaces of joints and the elastic frames of soft parts, such as the outer ear, the nose, etc., and constitutes the tendons of muscles ; nervous tissue constitutes the substance of the brain and nerves ; connective tissue is the delicate, membranous sheet which invests muscles and all the organs of the body, holding them in place, and separating parts from adjacent ones. Its chief use is that of support. Osseous tissue comprises the bones and the teeth.

18. The Fluids of the Body. — The blood is the most abundant fluid of the body, being estimatedat about one-eighth of its weight. Beside the blood there are the fluids enclosed in the eyeballs, the tears, the saliva, the bile, the intestinal juices, the synovial fluid of the joints, etc., all of which will be more particularly noticed later.

19. Organs and Systems. — Any definite part of the body that has a special office or function to perform is called an organ (Lat. organum). Thus the heart is the principal organ for the propulsion of the blood ; the lungs the prin-

INTRODUCTORY. J

ciple organs of the breath ; and still more familiar, the eyes are the organs of sight, and the ears of hearing.

20. A number of intimately related organs engaged in the performance of the same general function constitute a system. Each set of organs is so arranged as to perform special offices of its own while acting in harmony with all others. Thus we have the osseotis system, consisting of the bones, which gives support, protection to others, and supplies levers for the muscles ; the muscular system, composed of the muscles, supplies the means of motion to the body as a whole, and to each of its various organs ; the digestive system, comprising several organs, converts food into material for the nutrition of the whole body ; the circulatory system, composed of the heart, arteries, veins, etc., is employed in circulating the blood, thereby carrying nutrition to the various parts of the body ; the respiratory system comprising the lungs, air-passages, and certain muscles, etc., is employed in supplying oxygen and purifying the blood ; the nervous system, consisting of the brain and nerves, presides over all motion and sensation ; the organs of excretion, such as the kidneys, sweat-glands of the skin, etc., remove the effete material that can no longer be used in the body. In addition to these systems of organs, we have the separate organs of the special senses, the eye, ear, nose, tongue, and skin, by means of which we enjoy relations with objects in the world about us.

21. Public Hygiene ; Personal Hygiene. — Hygiene takes cognizance of every cause and condition which contributes to the maintenance of health and the prevention of disease. Owing to the absolute necessities where mankind is congregated in large numbers, as in towns and cities, every civilized nation or community enacts laws which deal with questions of health and the prevention of the spread of

disease. Sanitary regulations prescribe the conditions of abodes and their surroundings, as the carelessness or ignorance of an individual is liable at any moment to endanger the safety of his fellows. The removal of noxious refuse matter, the preservation of the purity of air and water supply, the wholesomeness of articles of food offered for sale, etc., receive more or less attention through legislative enactment. The isolation of persons sick with dangerous contagious disease, and the disinfection of clothing, utensils, and apartments to destroy the germs of disease, receive the supervision of public authority. By such means are prevented many of the ailments which shorten life and decimate the population.

22. But the intelligent culture of health by the individual far exceeds in power and effectiveness the mandates of nations, states, and cities in regard to health. It is through the acquisition of health-knowledge and the observance of persojial hygiene by individuals that good health and prolonged life are to be attained. Disease and suffering are largely the results of ignorance. The lessons taught by the science of health to the individual are essentially those which form the basis of the compulsory health enactments of civil government. Every individual should become acquainted with the nature of foods, and the quantity necessary under varying circumstances ; the proper preparation of food, and the conditions required for its complete digestion. He should understand the properties and effects of the beverages which he imbibes. The composition of air, the sources of its impurities, its effects when impure, the means for the expulsion of effete air and its replacement by that which is pure, should be

POINTS SUGGESTING QUESTIONS. 9

known. The relations of exercise, rest, sleep, cleanliness, and clothing to health should be understood. The hygiene of sight, hearing, etc., should be familar knowledge. Finally, every individual should acquire knowledge which will enable him to render aid in emergencies and in the absence of the physician or surgeon.

" Nature does require Her time of preservation, which, perforce, I, her frail son, amongst my brethren mortal Must give my attention to."

Shakspeare.

Points Suggesting Questions.

{Note. — It is desirable that questions should be given in such an order as to form a systematic and progressive development of the subject, and so varied as to cause the same facts to be viewed in different aspects and relations and to require a different form of language in the answer. Hence it is that good teachers do not allow themselves to be fettered with the set questions of a text-book, however good they may be in themselves. Instead of formal questions, therefore, a series of suggestive points or heads for questions is appended to each prominent division of the text.)

1. Object of experiment and investigation; what stimulates inquiry.

2. Utilizing knowledge of structure and function; arbiters of our own health.

3. The subjects of study. 4. Anatomy defined; the microscope and dissection. 5. Increased knowledge and accuracy; surgical skill, operations. 6. Physiology defined: experiments on animals. 7. Animal and vegetable physiology. 8. Hygiene defined; medicine and hygiene contrasted. 9. Scope of health science; tributary sciences. 10. Simple substances or elements. 11. Composition of the body; proximate principles. 12. Classes of proximate principles in body, 13. Constant change and renewal; elements in food; distribution by blood. 14. Hunger and thirst. 15. Cell structure; a cell; nuclei; protoplasm; multiplying of cells. 16. Tissue. 17. Classes of bodily tissue, peculiarities. 18. Fluids, quantity, location. 19. An

IO ACADEMIC PHYSIOLOGY.

organ; a system. 20. The various systems and their functions. 21. Cognizance by hygiene of causes, etc.; necessities where mankind is congregated; sanitary regulations; ignorance of the individual, danger. 22. Indvidual culture of health important; disease and ignorance; knowledge required by the individual, special.

THE OSSEOUS SYSTEM, OR SKELETON.

Chapter II. Composition And Structure Of Bone, Etc

1. Composition of Bone. — Bone is composed of organic and inorganic matter, or in other words of animal and earthy matter. The animal matter is largely gelatine ; the earthy is principally phosphate of lime, with some carbonate of lime and small portions of other earthy material.

2. The proportion of animal and earthy matter varies with the age of the person. In infancy the animal matter predominates, the bones being soft and constituted chiefly of cartilage in which earthy matter is afterward deposited. Later in childhood the animal and the earthy matter are about equal, each forming one-half the weight of the bone. In adult life, or in middle age, about four-fifths of the bone is earthy ; in extreme old age the bones are still more largely composed of mineral matter.

3. The bones of the very young, composed largely of gelatine, will frequently bend instead of break when subjected to violence, and hence are liable to be distorted by confinement in improper positions or by pressure upon them. In adult life the bones are strongest and firmest, though retaining a degree of elasticity. In old age the

ii bones become very brittle and liable to fracture, and when broken heal slowly and often with difficulty. Thus are shown the uses of the composing materials — the earthy material giving firmness, and the animal matter tenacity and elasticity to the perfectly developed bone.

4. In healthy bone the proportions of organic and inorganic matter are such as to give elasticity combined with sufficient firmness. In the disease called Rachitis or "Rickets," there is a deficiency of the earthy matter, and the bones being therefore too pliable and soft, deformities ensue, such as bow-legs, badly formed arms, ribs, etc.

5. Structure of Bone. — Excepting the joint surfaces, which are covered with cartilage, the bones are covered with a thin, tough, white membrane, known as the periosteum (Gr. peri, around ; and osteon, bone), or bone-covering. This membrane adheres very closely to the bone, and in it ramify the blood vessels which supply nutrition to the bone. 1 From these blood vessels smaller branches penetrate into the substance of the bone through small apertures called Haversian canals (from Havers, the anatomist, who discovered them).

6. As the periosteum is the source from which the bone receives its supply of nourishment or building material, a portion of bone or even an entire bone may be removed, and, if the periosteum is saved intact and in place, new bone will be developed and replace the bone removed. As an example, we cite the case of a woman whose lower jaw-bone having become diseased, it was found necessary to remove it. The operation, performed by the late Dr. James R. Wood, of New York, was successful ; the peri-

1 When a bone is severely bruised, inflammation sometimes takes place in the bone-covering and a painful felon results.

osteum being saved and kept in place, a new jaw-bone was produced in due course of time.

7. The long bones are composed externally of a dense layer of bone tissue, ivory-like in texture, enclosing a hollow space or canal. Their extremities are widened to form the joint surfaces, and are covered with cartilage. The hollow shaft is filled with a pinkish, fat-like substance called marrozv. Blood vessels ramify through it and furnish nourishment to the inner surface of the shaft. Designed to serve as columns or as levers, the long bones are admirably adapted to this purpose. Their hollow form gives lightness, and, at the same time, greater strength than the same amount of bone would have in a solid form of equal length.

8. The short bones are composed of a hard, ivory-like layer externally, and are softer or spongy in texture within. They are comparatively light in weight, and are found in parts where only a limited motion is required.

9. The fiat bones comprising those of the skull and other cavities, are composed of two layers of hard bone tissue which enclose spongy bone substance. They are adapted to surround and protect various internal organs of the body.

10. Cartilage. — The cartilages belong to the bony system, and are what might be called fibrous tissue in a state of change to bone substance ; but all cartilage is not destined to be changed into bone tissue. Cartilage is tough, elastic, flexible, and either yellowish-white or pearl-white in color. It forms the surfaces of bones in movable joints, furnishing a smooth, glistening surface, and unites bones at points where the frame-work must yield to expansion, as in the chest. It also forms the flexible skeletons of certain parts, as those of the external ear, nose, eyelids, etc.

11. Growth and Repair of Bone. — There is a vast difference between living bone and dead bone. We usually obtain our ideas of the bones comprising the human frame from the dried, bloodless specimens we see in museums and lecture rooms. Living bone, being well supplied with blood by the blood vessels of the periosteum and the marrow, is of a pale pink color on the surface, and deep red within.

12. At the ends of the smaller canals of the bone lie the little cells, and these absorb nourishing and repairing material from the blood. The bones are built up, and eliminated particles are replaced by others, in the same way that the nourishment and repair of the softer tissues are accomplished. The cells of the bones have the special function of selecting from the blood that which is necessary to form bone tissue.

13. The constant change of particles in the tissues can be easily demonstrated by the change of color that may be produced in bone by mixing madder with the food of animals. The bones soon become red. This color disappears when the coloring matter is withheld for a time, but reappears when the food is again colored.

14. Repair of Broken Bone. — A broken bone is healed by the active work of the cells that remain uninjured.

When the ends or edges of the fragments are properly placed together or "set," healing proceeds by a natural process, the bone being repaired in the same manner in which it grows. The cells send out first a watery fluid between and about the fractured ends. In the course of a few days this fluid becomes thicker, more jelly-like, and is gradually hardened by mineral matter which the cells deposit. In a few weeks the deposited matter becomes firm enough to hold the bones in place. The new material deposited does not, however, become as hard and firm as the old bone for several months, and hence it is requisite to exercise care in the use of the injured bone during that period.

15. The process of healing varies in length of time with the age and general condition of the individual, being more rapid in the young than in the old. In advanced age fractures are sometimes exceedingly slow in reuniting, and in some cases union cannot be effected at all : in this way is indicated the general decline of the vital reparative processes in the aged.

Chapter III. The Skeleton

1. The Skeleton and its Functions. — The word skeleton (from Gr. skello, to dry) signifies literally the dry or hard parts of the body. When used ordinarily, it applies merely to the bones ; but in a broader sense it includes not only the bones, but the cartilages and membranes which complete the framework of the body. By some anatomists the teeth are also considered as belonging to the skeleton.

2. The skeleton serves as a basis of support for the soft parts, affords surfaces of attachment for muscles, protection for many delicate organs, and gives general outline to the body. The bones composing it vary in size and shape according to their location and office, and are bound together by fibrous bands, called ligaments. In the adult there are about two hundred separate bones, not including i6

ACADEMIC PHYSIOLOGY.

the teeth and the small bones of each ear. In the child they are more numerous ; and in the process of development of the skeleton, certain bones become united.

3. For convenience in classification the bones are divided into those of the heady trunk, the upper and the lower extremities. The head has twenty-two bones, the trunk fifty-two, the upper extremities sixty-four, and the lower extremities sixty-two. i

Fig. 2. — The Skull {Front View). i, frontal bone; 2, parietal bones; 3, temporal bones; 4, portions of the sphenoid bones, forming the backs of the orbits of the eyes; 5, nasal bones ; 6, superior maxillary bones; 7, inferior maxillary bone ; 8, malar or cheek bones.

4. The Head. — The bones of the head are subdivided into those of the cranium or skull, and those of the face ; of the former there are eight, and of the latter fourteen.

5. The bones of the skull are separate in infancy and childhood ; but in the adult they become firmly united by irregular, immovable joints called sutures (Lat. sutura, from suere> to sew or stitch), and thus form a strong, rounded case for the lodgement and protection of the brain and the organs of the special senses. These bones have been named according to their shape or location, as follows : the occipital bone, at the back and base of the skull, contains an aperture for the passage of the upper part of the spinal cord, and sends off two projections which join with the first bone of the spine to provide for the nodding movement of the head ; the two parietal bones form the sides and top of the skull ; the frontal bone forms the front of the skull and parts of the cavities of the nose and the orbits of the eyes ; the two temporal bones form part of the sides and base of the skull, and contain the cavities of the organ of hearing ; the sphenoid bone, resembling a bat with outstretched wings, forms the central portion of the base of the skull ; the ethmoid bone, located in the front part of the base of the skull, forms part of the cavities of the nose and the inner boundaries of the orbits of the eyes. In addition to these are the four small bones of the middle cavity of the ear.