The physiology and hygiene of the house in which we live

Front matter

COLUMBIA LIBRARIES OFFSITE

HEALTH SCIENCES STANDARD

RECAP

Preface

The body, in this book, has been likened, in its various parts, to a house, and it may be truthfully claimed that no other of man's dwellings has as many "modern conveniences " as his body. There is nothing that his ingenuity has yet devised for the safety and comfort of his home that he may not find foreshadowed, and usually bettered, in the body. Where, for instance, can you find an automatic steam or hot-water heater that will perform its work as well as the thermogenetic system of the body ? Where can the block or building be found that is as well sewered and ventilated ? Furthermore, he finds in this house of ours elevators, telegraphs, and telephones innumerable, also pictures, photographs, library and music-rooms, and a dining-room from twenty to thirty feet long. But the best of all are the hosts of trained and uncomplaining servants that go with the premises ; porters, cooks, waiters, messengers, photographers, carpenters and joiners, are all found on the estate, and ready to work without other wages than food and lodgings for their life-time, and they never leave the property on any pretext whatever.

Moreover, this house of ours is portable, and can be moved whenever we please ; and, what is more remarkable, this house of clay, as the theologians call it, can be

■k Preface.

rented for a term of years under the most reasonable conditions. All the Landlord asks in return is that the premises should be kept in good repair. Surely the terms are not hard, not difficult to comply with ; but, light and easy as they are, the penalties attached to non-fulfillment are heavy. Health is prompt and cheerful compliance with the terms upon which we hold our bodies. Disease is our witting or unwitting breaking of them. Hence the absurdity of the question, " Why is not health catching instead of disease?" Disease never occurs until the laws of health have been broken somewhere — either by " this man, or his father," by violation of personal or public hygiene. This little book is designed to aid, as far as possible, its readers to keep these laws, and in so far as it accomplishes this, its purpose has been fulfilled.

M. P. Hatfield.

Chapter I. Mosaics And Tapestries

The body a mosaic — Hair follicles, number — Epithelial scales — Germinal matter — Karyokinesis — Protoplasm, and alcohol — Blisters — Hairs in court — Cowlicks and goose-skin — Care of the hair — Wigs and hair-dyes — Dandruff— Furred tongues and finger-nails — Corns, scars, cartilage — Areolar tissue, fascia — Wrinkles — Rameses Page 9

Chapter II. Beams, Rafters, Cushions, And Servants

Two hundred and forty timbers, long, flat, short, irregular — Rickety houses and children — Skull, cupola, "brain shell" — Cowley's comparison, cubic contents and greatness — Phrenology and sinuses, fourteen face bones and uses, seven neck bones and mechanism — Atlas and axis — Crooked backs and round shoulders, how made and how remedied — Five sections to arms, horses', pigs', and monkeys'; Ribs and thorax; Body really a double tube, Chinaman on corsets, and Dr. Brown on fashion — Backbone, thirty-three levers, Pott's disease, bumpers in back-bone and why shorter at night than in the morning, Rabbi's immortal bone — Chemistry of the bones — Fossil soap, adipocere and Frenchman's soap — Earthy part of bones, peculiar markings — Growth requires twenty to thirty-five years — Varieties of joints, and why — Walking, what — The uses of muscles, etymology, number, Darning of more important groups — Voluntary and involuntary — How differ— Necessity for involuntary — Striped muscular tissue — Checkers in a purse — Delicacy of action — The hand as a machine — All work moving something — Skill, exactness of muscular action — Cramp, what — Muscular sense — Blind physicians, tailors, postmaster-general — Wonder of walking, muscular growth, heat, and exhaustion — Starved muscles — Calisthenics

0 COKTBNTS.

versus house-work — Folly of laziness — Blessing and necessity of work — Paralysis — Death of muscles — Rigor mortis — Necessity and uses of fat — Where found— Starvation— Shakespeare on fat— Fat globules— Cellular tissue a buttery, marrow a preserve closet Page 25

Chapter III. Dining-room, Cooks, And Scullions

Food, what, necessary elements (15), and where used, bricks and mortar of house, proximate principles, groups, body chemically an egg — Three groups of foods required — Frenchman's scheme to make a body, why failure— Cooked versus raw food — Teaching of teeth concerning food ; Tooth dyspepsia, grinders required, why two sets, parts of a tooth, enamel prisms, toothache, decay and candy — False teeth not new — Chinese tooth carpenters — Eupepsia, what — Digestive ferments — Antiquity of pepsin — Chyme, chyle, lacteals, and lymphatics, lymphatic glands — Scrofula — Gluttony more frequent than drunkenness — John Wesley's rules — Adulteration of food — Cost of food — Carbonaceous foods and heat 60

Chapter IV. The Wheel At The Cistern

Eastern irrigation — Aptness of the comparison — Size of the heart — Daily work — The heart pump, parts and valves — Heart disease and sudden death — Size and place of heart, apex beat, the round of circulation — " Chair courante," color and chemistry of blood, red rouleaux, white corpuscles, hasmatoblasts, amoeba, pus corpuscles, inflammation, Nature's surgery, fi brine, importance of, " Bleeders," corpuscles Swiss body-guard, numbers, coats of arteries, veins, intervascular spaces — Fainting, blushing, vasomotor system, heating the body — Coagulation of the blood, fibrine, exercise — Jenness Miller costume — Tobacco heart — Apoplexy 94

Chapter V. Sewerage And Ventilation

Skin more than an elastic bag — Its miles of tubing remove one half sewerage of the bod}r — Relation of skin to kidneys — Pope's gilded boy — Water cures, rubber bandage, relation of perspiration to heat — Fatality of burns, and why — Lymphatics of skin — Lymph spaces — Tonsils and relation to liver — Liver, what — "Blue devils" — Ur.ea ashes, uric acid cinders — Diabetes

Contents. 7

— Anatomy of the kidney — Dropsy, catching cold, cold feet and death — Creatin and creatiuin, typhoid fever, filth diseases— Ptoaminea and leucoamines — Effects on system, life an eddy — The body's Gehenua — The wisdom of Moses — Earth closets — Dangers of constipation — Saint Simeon Stylites — " Fear God," etc. — Keep the body clean — Importance of ventilation — Black Hole at Calcutta — Asphyxiated prayer-meetings — Ranch and Adirondack cures — Quantity of air required for adult, sleeping-rooms, body, how ventilated— Principle that of latest science — Cilia of air-passages — How not to die of consumption — Tidal air, its impurities, respirators — Chloride of palladium alarm — Sewer-gas and diphtheria — Surgical pavilions Page 128

Chapter VI. " The Daughters Of Music, And They That Look Out At

THE WINDOWS."

The tongue's box, not necessary for speech, Paul and 0. W. Holmes, Unguals, labials, and palatals — Need of soft palate — Epiglottis, larynx, vocal cords, speaking machines, audiphone, clergyman's sore throat, errors in public speaking, John Wesley's prohibitions — Turbinated bones — Nasal catarrh, cigarette-smoking — Catiline's "Keep your mouth shut" — Eustachian tube, bones of the middle ear, membranes, windows, semicircular canals, cochlea bags, semicircular filaments, otoliths, aural staircase, rods of Corti, eight thousand tuning-forks — Rood's resonators, sound-waves, limits of hearing — Music and rods of Corti — The new song and the music of the spheres — " Eye hath not seen " — Camera whose negatives are preserved — Retina, first plate — Lens, dark box, screens, diaphragm, lids, and lachrymal apparatus — Why cry — Lachrymal duct, handkerchiefs and tear jugs — Red eyes — Leah — Cross eyes and remedy — Muscles of lens — Headache from eyetire, far sight with age, spectacles, albinos, beauty and use of iris, light in brain, not eye — Seeing stars, vitreous and aqueous humors — One-eightieth inch retina, rods and cones — Length of impression, wheel of light — Light for reading and whence, black spots, blur, dread of light, twilight reading, twitching lids, eyes versus ears 1 G3

Chapter VII. Telegraphs And Phones

Body in threes — Nerve first telegraph cable — Substance of Schwann, sheath, axis cylinder — Plexus — Ganglion a relay station — Sympathetic nervous system — "Involuntary nerves" — Neurasthenia-Spinal cord, A. M. and P. S. roots— Pile of ganglia — Brain knots — Brains of insect-, corpus

8 Contents.

callosum and dusty blanc-mange, ventricles, nerve cells and tubes- Student's comparison of membranes of brain, " spider's web " — " The tree of life" — Crumpled cloths — Medulla and relation to P. S. ganglia — Two hundred and sixty feet per second quick as thought, 3,155,160,000 ideas — Phosphates and thought— Neuralgia — Exhausted batteries — Sleep, victory of sympathetic over cerebro-spinal — Amount required — Insomnia and business— Dreams — Somnambulism— Mental habits, memorj' — Soul's picture house vs. Pompeiian frescoes — As a man thinketh so he is — Mrs. Browning on reading — Newspapers, slang and gossip, and habit — White Cross Knights Page 185

Chapter VIII. Moth, Rust, And Microbes

Mortgage with each lease — Foreclosure largely optional with tenant — Terms irrevocable, and the best possible under the circumstances — Earache and brain fever, diphtheria and filth — The place of the doctor — Faith cures — Dr. Buckley — Hercules and the wagoner — The mystery of death and suffering — Hilton on pain — Saxe Holm — Chinese and cholera — Providence never does for us what we can do for ourselves — Gold, silver, grain, timber— School-house to study the works of God — Ourselves not least — Neglect of body for books foolishness, since only one lease permitted — Paul's letter to the Corinthians — The body a Shylock when wronged — Rack-rent — Law inflexible but just — Ignorance no bar — As yet in part — Through a glass, darkly — What science has to say of moth and rust — Aptness of terms — Oxidation — Erernacausis — Life a perpetual miracle — Why — Moses's bush a type of the body — On microbes and bacteria — Definition, varieties — Torula and fermentation — Sore mouth — Anthrax — Scarlet fever — Tuberculosis — Malaria — Beale on bacteria — Fascination of the subject — Infinitely great and little— Wordsworth 210

Part Ii.— Appendix

Practical hints in regard to the care and development of the body, according to the methods of Dr. Anderson and Wm. Blaikie 257

Index 211

Physiology and Hygiene.

Chapter I. Mosaics Axd Tapestries

There are at Rome four marvelous mosaics. Viewed from the pavement beneath they appear like exquisite lifesize paintings representing the four evangelists, but with a nearer approach they become gigantic in their proportions, and it is found that their Avealth of color and beauty of form are due to bits of colored glass and stone, so skillfully arranged that at a distance they produce all the effect of an oil-painting.

So it is with the human body when studied beneath a microscope. All the beauties of color and form of this earthly habitation are there found to be due to a marvelous mosaic of cells whose workmanship is more exquisite than that of any Roman or Florentine workman. Even an ordinary hand-glass will reveal the ragged edges and rough joinings of these pictures in stone, but the finest microscope fails to show any imperfection in the finish of the mosaic of cells found in the body. Take for instance the cross section of a single human hair and the sac in which it is held. In what king's palace can a more beautiful piece of mosaic be found than this ? German patience, like divine wisdom, has recently taken the time to number the hairs of our heads, and iimls that a red head has 90,000 of these mosaics, a black 108,000, and two brown ones 109,000 and 140,000

Physiologt a.m> Hygiknb.

respectively, and each one perfectly shown in the cut.

Cross section of human hair follicle, showing outer fibrous coat, basement membrane, outer root sheath, polyhedral cells, inner root sheath, and hair itself.

finished with a dainty care im- No wonder Paul declares that a woman's hair is her glory.

What would he have said could he have looked through tlie modern microscope, which reveals thousands of wonders never dreamed of without its aid ? And yet we take weary journeys to far-off Rome and Naples to see Pompeian mosaics without a tithe of the beauty of those we carry about with us daily.

Nor are the tissues, or tapestries of the body less wonderful than those of the Gobelin factory, which cannot produce such a sack as the human integument, or skin. Such another bag was never elsewhere woven, for its fabrics are so delicate that they need to be kept covered with fine powder lest they should be injured. Histologists call this powder dried epithelial scales, and with these the whole surface of the body is dusted in layers of various thickness, always deepest where there is the greatest pressure. Hence, on the soles of the feet and the palms of the hands the outer layers of the skin become thick and horny ; but epithelial scales are found every-where else as well, completely covering the surface of the true skin, which lies beneath, and is thus protected by these fine white scales, softer than snow and serving a not dissimilar use. Take the blade of a penknife and gently scrape the back of the hand, and in a few seconds these scales may be found as a fine white dust on the knife blade. So light and impalpable is this epithelial powder that a breath carries it away, and fortunately so, for otherwise we should grow as thick-skinned as a rhinoceros. Layer after layer of these

Mosaics and Tapestkies. 11

dried scales are continually falling from the surface of the body in larger numbers than the dead leaves of an autumn forest, so that epithelial scales can be found every-where that dust gathers, "from the tops of the highest mountains to the innermost recesses of the pyramids." And whence comes this never-ending supply of fine, branny scales ? They are pushed up from below by an incessant growth of new integument, or skin, which shoulders away the parent cells which produced it, and thrusts them out to die of exposure, like a pious Hindoo on the banks of the Ganges. Integument consists therefore of two kinds of matter: loose white scales on the surface of the body and the rounder, moister ones beneath ; the former are dying or dead, and the latter are alive, and possess germinal matter.

Germinal matter, so named by Dr. Lionel Beale, is perhaps the most marvelous thing in all the human body. It is, in a certain sense, its builder ; for there is a time when the body begins its existence as a transparent mass in which are imbedded granular points. These differ from the matter in which they are imbedded by the latter refusing to take a stain from a carmine solution, which readily tints germinal matter with its characteristic color. This germinal matter is almost as transparent as that by which it is surrounded, and, so far as can at present be ascertained, is perfectly structureless. It consists of minute points not larger than one fifty-thousandth of an inch in diameter, scattered or in groups, and always surrounded by larger or smaller quantities of so-called formed material (matrix). This formed material is supposed to be the product of germinal matter, and, unlike germinal matter, has no more vitality than any other organic compound. Like other organic matter, formed material is subjected to the usual laws of chemistry, and is oxidized and changed like similar material outside of the body;, but germinal matter resists such agents, and as long as it lives possesses the property of being able to project one part of itself in advance of the remainder. In this way germinal matter may travel directly through any of the tis-

Physiology and Hygiene.

sues of the body, apparently using formed material for nutriment as it divides and subdivides. The chief work of germinal matter seems to be its division and subdivision; upon this the growth of the tissues depends, while cell walls and intermediate substance (formed material) become variously modified and form the various parts of the body, such as bone, cartilage, muscle, and integument. And thus it is the body grows, germinal matter breaking up into smaller portions, or nuclei, as they are called, each taking a spheroidal portion of formed material with it, and dividing and subdividing as growth requires, often after the most intricate fashion, weaving itself into graceful stars, loops, rosettes, wreaths, etc. (such as here figured), infinitesimally small, of course, for they can be seen only through a microscope.

Upon these freaks of motion, for such they seem, depend the existence of the body; for these twistings and turnings of germinal matter precede its selfdivision, and upon its subdivison depends the multiplication of cells and all that it implies in the matter of growth and decay.

Germinal matter is the same thing as the protoplasm over which the scientists and theologians have often so unwisely fought. Protoplasm is not God, as some of the scientific men would have us believe, but, on the other hand, it as really exists as air, and is as capable of being shown in its wondrous work. Denying the existence of protoplasm, or whatever you may prefer to call it, does not abolish it. It may be used unfairly as a weapon against revealed religion, but too many such efforts have failed in the past, to give the Christian any uneasiness in re-

Karyokinesis, or movements of cellular protoplasm.

gard to the final outcome. Let him wait patiently, and he finds that his enemy's weapons become his best defense, as to-day one of the weightiest arguments against alcohol is framed from its effects upon this germinal or protoplasmic matter. ^

Strong alcohol dropped on heart muscles first paralyzes, then kills, this germinal matter. But, it may be said, only dilute alcohol is used for drinking, and this, when taken into the circulation, quickens the heart's action. Yes, temporarily, as it also makes us for a time think ourselves wiser and stronger than any one else. "O," says Dr. Holmes, "if the alcoholic virtues would only wash! " But, alas! they will not, for the poem, the book, the lecture delivered under alcoholic stimulus is never taken elsewhere at its valuation. The dynamometer is pitiless in its verdict, and that says absolutely that these servants of ours cannot lift, pull, or do any kind of work as well after as before the glass of whisky that makes one feel — that is exactly it: apparently, not really — stronger; for physiological experimentation proves that alcohol, in whatever form, diminishes the sensibility and lessens the contractility of germinal matter wherever it is found. Dip your fingers into alcohol, and after a little you will find them numb from the effect of the alcohol upon the germinal matter of the skin, for it is this germinal matter that perpetually renews the loose scales which make up the outer or scarf skin, which protects the sensitive nerves and tissues beneath. The necessity of such protection is shown whenever the scarf skin is removed, either by rubbing or blistering, and the sensitive true skin exposed to the air. This same is seen in a chapped skin, which is one from which the outer layer of epithelial scales has been removed by cold or irritating fluids, leaving the lower and softer layers to crack and bleed. This will be readily understood by a reference to the annexed cut, which represents the different layers of the skin on the tips of the fingers. The ends of the nerves and the blood-vessels of the skin are not well shown in the picture, which is simply designed i<> show ihe epidermis, <>r layer

Physiology and 1Iy<jiene.

of dried scales, basement membrane, and a soft layer of granular and germinal matter beneath, constituting the corium,

Section of the Skix. a. The epidermis, h. Two of the quadrangular papillary clumps composed of minute conical papillae, such as are seen in the palm of the hand or the sole of the foot. c. Deep layer of the derma, the corium. d. Tactile corpuscle.

or true skin. Through the skin pass several miles of sweat glands, hereafter to be described; and in it are also imbedded the hairs, nails, and sebaceous glands.

Hair is designed to form an elastic protection and adornment for the head. Minute hairs are, with few exceptions, also found every- where upon the surface of the body; but they are, if we are to believe the evolutionists, the useless heritage left us by our great grandfathers, the apes. A fine head of hair is a gift to be proud of, whether black, red, or gray; for the best art of man has never yet succeeded in making a satisfactory substitute, and it never will until it succeeds in making as exquisite a hair factory as that found in a hair follicle. A single hair is an insignificant thing, according to our way of thinking, but in the biblical sense of the statement our hairs are all numbered; for more care is shown in the arrangement of a single hair follicle than in an elaborate mosaic (page 10). First, we find a fibrous sac (h) lined with glassy membrane (</), inside of which are set the outer and inner root sheaths (d. e.f), most beautifully constructed of cells containing dark poinds of germinal or growing matter, and internal to this the cuticle of the hair (<:;), its cortex, or bark (&), and its marrow, or pith (a) ; for hairs possess marrow no less than bones. More properly, it resembles the pith of a feather, for it does not answer in any wise except in name to the marrow of the bones, which is largely fat. The fat of the hair is found in two little sacs, which serve a similar purpose to those found on a larger scale on the backs of water-fowl, located at the base of each hair (sebaceous glands). Man is in reality feathered, although Plato defined him as a "featherless biped;" but with better eyes he would have found that his definition was not scientifically correct, for a hair is essentially the same thing as a feather. They both have a central shaft, a pith, and a vane of barbs; but in the hair these encircle the shaft instead of being arranged laterally as on a quill. These barbs are proportionally smaller in the hair, but still they may be felt, even when they cannot be seen, as is readily proven by pulling a horse hair the wrong way between the fingers. The barbs or scales of a human hair overlie each other like shingles on a roof, and are unlike those of other animals. Microscopists are able, therefore, to tell with certainty from what animal a hair lias been taken.*

A hair is prolonged at one end into a sharp, tapering point, and at the other it is expanded into a root, or bulb, as it is well named. Each hair bulb is set into a flask-shaped pocket

* In the late Piper case tried in Boston the guilt of the prisoner was established by a single human hair adhering to the inside of the prisoner's coat; and Gosse relates the following more remarkable case: "The knife of a prisoner on trial for murder was found to be stained with blood, which contained a single hair. The prisoner claimed that the knife had been used for killing pigs ; but the microscope proved that the hair was not a pig's bristle, but a squirrel's hair; and as the little girl who had been murdered had worn at that time a squirrel boa, the chain of evidence was complete."

or depression in the skin, very much as children thrust twigs into soft clay, and the bottom of each pocket is lined with points of germinal matter, which reproduce the hair continually. Sometiiftes nature plays strange pranks in planting these bulbs, and instead of planting them in regular rows sets them round in circles, and then their unfortunate owner discovers, to his great annoyance, that he is the owner of a "cowlick," which requires all his patience and pomatum to keep in subjection. Fright and cold may also produce, on a small scale, temporary cowlicks; for attached to the base of each of these hair pockets are two miniature, involuntary muscles, by whose contraction some of the lower animals, as the horse and pig, erect their hair. In man these muscles are only influenced by cold or fright, which produces that condition of the skin known as " goose-skin," due to the Longitudinal section contraction of these tiny muscles. rXCJTJX A hair, in its structure, is ss delicate as the papilla, and tbe muscle finest feather; and while it is exceedingly (museums erector piii). elagtiCj and perfectly adapted for the purpose for which it was designed, it cannot be frizzled and burnt and broken without destroying its beauty and its life. A hair curls for the same reason that a shaving does; namely, they are both flattened cylinders. The more nearly cylindrical a hair, the stiff er and straighter it becomes, as is seen in the Indian, while we find the opposite extreme in the negro, whose hair cylinders are so much flattened that they become kinky as wool despite the owner's efforts to the contrary.

The coloring matter of the hair is located in the pith, or central part, and its gloss is due largely to nature's pomatum pots, two of which are attached to the root of each hair, so that other dressing for the hair than a brisk brushing with a stiff brush is hardly ever required.

All other applications, unless it be a little water or vaseline, are untidy or injurious, except in cases of diseases of the

Mosaics and Tapestjues. 17

scalp, when a physician's advice should be taken instead of an "almanac's tonic." Patent hair dyes are especially to be shunned; for with very few exceptions they owe their value to lead salts, and these, sooner or later, produce poisoning and paralysis. No one in his senses was ever long deceived by dyed hair, although the attempt is as old as the time of the Pharaohs; but the Egyptians were wiser than we, for they shaved the obnoxious hair off from their heads and wore, instead, wigs dyed to order. Artificial hirsute abominations date back to Margaret of Navarre. " Margaret of Navarre," says history, " having through sickness lost her blonde locks, cut off similar ones from her plebeian subjects and wore them instead of her own." History repeats itself, and every town has its local Margarets, who borrow their coiffures or bleach their own locks by means of peroxide of hydrogen, and thereby permanently injure their hair. Gray hairs are a crown of glory, says an excellent authority. Moreover, as yet, no device has been found that will safely restore them to their original color. Early gray hairs and bald heads are part of the price that is paid for modern civilization; and the only way to defer the inevitable is to keep the head cool, occasionally washed free from dandruff with a little borax and water, and the hair thoroughly brushed with a stiff brush several times daily.

Dandruff is simply another name for the dead, epithelial scales found every-where on the surface of the body; but being confined to the head by the hair, they are apt to accumulate until they become a source of annoyance to the possessor. Unless it arises from a diseased seal}), dandruff may be readily removed by washing the head with a solution of borax or salts of tartar, either of which readily dissolves these scales, but requires that the scalp should be washed immediately after with pure warm water. Similar treatment will remove the coating on the tongue, observed in many disordered conditions of the system. It would be a Hibernicism to peak of this coating on the tongue as a dandruff of the mouth, but in reality both are due t<» a similar cause; namely.

18 Physiology and IIvgiene.

excessive death of epithelial cells, which in consequence accumulate instead of being, as usual, swept away as fast as they die. In case of the tongue, the reason of this undue accumulation is congestion of the membrane lining the mouth, causing an increased growth of the cells on the surface of the tongue, which remain pasty and white or may become dried and colored by the disordered secretions of the mouth. The secretions of the mouth are as a rule diminished at such times, and hence are insufficient to remove the fur, which in protracted fevers continues to increase, unless removed, adding greatly to the discomfort of the sick. There is, however, no better reason for allowing this to remain in the mouth than dirt elsewhere upon the surface of the body. It can easily be removed by scraping with the sharp edge of a penknife ; and the mouth of a f ever patient should no more be allowed to become unclean than his face.

The relation of a furred tongue to finger-nails may not be apparent unless it be remembered that the nails, like the fur upon the tongue, are epithelial scales packed closely together. With proper treatment under a microscope they can be shown to be identical, with, however, this very great difference: the fur upon the tongue is dead and decaying matter, fit only to be thrown out of the body, while the nails, though hardly less vital, are admirably designed to protect and assist the ends of the fingers and the toes. A cutting of nail, even though it be not worshiped like that taken from the grand Lama of Thibet, is well worth our study. Examine a nail under a high power microscope and you will discover that it is made up of a multitude of little scales, so closely packed together, like figs in a box, that they are firm and solid and give the horny appearance to the nail. Beneath these we find softer, translucent cells (one fifteenthousandth of an inch) which are continually growing and producing new nail at the root and the quick; that at the root pushing the nail forward and free from the end of the finger. The cells at the quick of the nail are so much larger than when they crowded together above that, to accommodate them all, the bed of the nail is grooved or thrown into ridges into which the nail dove-tails, and thus, like a ship on the ways, is directed in the way in which it should go. As long as the bed of the nail is uninjured it will reproduce fresh nail, making an entire new one in four to six months; but if these ridges are destroyed a straight nail can never grow on that finger again, although nails have been known to appear on a second joint when the first has been removed.