Second book on analytic anatomy, physiology and hygiene, human and comparative With numerous illustrations

Front matter

1 LIBRARY OF CONGRESS.!

I'l^'-^P* I^fotw |o #

I UNITED STATES OP AMERICA. ^

Preface

This work is intended for classes in academies and grammar-schools. The leading aim has been to so limit its size as to finish it in a term of from ten to fourteen weeks. To accomplish this end, the '^ Xew Analytic Anatomy, Physiology and Hygiene, Human and Comparative, by Calvin Cutter, A. ]\I., M. D.,'^ has been followed in arrangement, in illustration and in general scope. Primarily, the work is designed for the class-room, but the brief suggestions relative to Minor Surgery and the Care of the Sick adapt it for general use in families.

The questions given at the close of each chapter may be used at the pleasure of the instructor. The first form educes a thorough analysis of each paragraph. The second is unijic, so that a blended investigation of such paragraphs as agree in structure, function or hygiene may form analytic lessons or reviews. The third form is topical, with diagrams and illustrations, to secure a synthetic review of each chapter and a summary of the work.

Care has been taken to adapt the work to Outline Anatomical Charts, Human and Comparative, which are as necessary an accompaniment as outline maps in modern Geography.

8 PEEFACE.

I am under special obligations to Isaac Walker, A.M., Principal of the High School, Ware, Mass., not only for the Analytic, the Unific and the Synthetic questions of the work, but for the critical examination of each Paragraph, Section, Chapter and Division of the "New Analytic Anatomy, Physiology and Hygiene, Human and Comparative," in his class-room.

Calvin Cutter.

Warren, Mass., July, 1871.

ANALYSIS OF CONTENTS.

DIVISION I.

SECT. CHAPTER L— GENERAL REMARKS. p^^j-g

1. The Three Kingdoms of Nature Compared 11-13

Appendix

CHAPTER XIIL

Caee op the Sick 279-284

Treatment of Wounds, of Burns, of Asphyxia 284-288

Poisons and their Antidotes 288-291

For Treatment of Wounds, page 284. For Recovery of Drowned Persons, page 287. For Treatment of Bums, page 286. For Treatment of Frost-Bite, page 287.

Anatomy, Physiology and Hygiene.

DIVISION I.

OUTLINE PKINCIPLES.

Chapter I. General Remarks

I 1. The Three Kingdoms of Nature Compared. — Essential Distinctions between the Mineral, Vegetable and Animal- Kingdoms. Nature of the Life-force. Vitalized and Non- Vitalized Bodies compared. Plants and Animals compared. Definition of Organs — Of Apparatus — Of Anatomy — Of Physiology — Of Hygiene — Of Histology — Of Chemistry.

1. "Stones grow; Plants grow and live; Animals grow, live and feel," was the Linnsean distinction between the three great kingdoms of Nature. Though imperfect, it is still suggestive of the boundaries of each division. The Mineral kingdom includes all things naturally destitute of life ; the Vegetable kingdom, all organizations having a certain type of life, but no power to feel or to will ; the Animal kingdom, those possessing a higher type of life and the powers of sensation and voluntary motion.

2. Inorganic or Mineral bodies are made up of atoms combined and arranged according to certain mechanical and chemical laws. ■ Organic or Vegetable and Animal bodies are combinations of like atoms, according to the same laws, controlled by Vitality or the Life-force. Plants have a vegetable vitality — animals an animal vitality. Of the real character of this life-force we know nothing. We are at liberty to examine her products, but the mighty principle upon which they are wrought she holds fast as a secret unrevealable to us with our present limitations.

3. Among the Distinctions between Oeganized or Vitalized, and Unorganized or Non- Vitalized bodies, are the following : 1st, An Organized body consists of an assemblage of parts called organs, having a mutual relation to, and dependence upon, each other ; these taken together constitute an individual, a being; therefore the parts when separated are incomplete, as in a divided plant. Not so with the Unorganized body : each fragment of a rock possesses all the essential characteristics of the original mass. 2d, Organized bodies, being subject to constant waste from vitalized activities, demand nourishment ; Unorganized bodies, being permanent in their nature, require no food. 3d, Organized bodies grow by means of particles of matter conveyed to their interior and there assimilated ; Unorganized bodies increase in size by simple layers upon the exterior : the former have a limit in size ; the latter have no natural limit. 4th, Organized bodies have their period of duration : decay and death await every living animal and vegetable; but, from the nature of the Inorganic world, we speak of the mountains as everlasting. 5th, Organized bodies have their particles arranged in lines generally more or less curved, with varying angles, as in animals and plants ; Unorganized^odAQ^ have their lines straight, with angles mathematically exact, as in the crystal of common salt. 6th, Organized bodies reproduce themselves, each species after its own kind ; Unorganized bodies have no such power of reproduction.

4. The Distinctions between Animals and Plants are important. Animals take in oxygen and give out carbonic acid gas ; Plants take in carbonic acid gas and give out oxygen. Animals subsist upon the products of the animal and vegetable kingdoms ; Plants, upon those of the mineral kingdom. Animals possess the power of sensation and voluntary motion ; Plants, neither. These distinctions are obvious and definite

GENERAL REMARKS. 13

in the higlier grades, but in the descending scale we recognize a gradual approach of plants and animals to each other, and likewise to the mineral kingdom ; so that in the lower forms of life all perceptible traces of organization disappear, and, like converging radii, the three kingdoms of Nature blend in one common centre.

5. An organized body consists of parts called Or'gans. A collection of organs so arranged that their combined actions shall produce a given result is called an Appara'tus. The definite, peculiar use of an organ or apparatus is called its Function : Example. — The digestive apparatus consists of the organs — teeth, stomach, liver, etc. — whose combined functions result in the digestion of food.

The description of the form and position of these organs is called Anat'omy;* the description of their functions, Physiol'ogy ; t the examination of the conditions most favorable to their health, Hy'giene. J

6. The organs are composed of a variety of structures, called Tissues, which are themselves composed of Cells. The, description of the form, color, constituents and origin of these tissues and cells, or their minute anatomy, is called Histol'ogy;§ the science which treats of their ultimate elements is called Chem'istry. ||

* Gr., ana, through, and tome, a cutting, f Gr., phusis, nature, and logos, a discourse. f Gr., hugieinon, health. § Gr., histos, a web, and logos, a discourse.

II Ar., kimia, hidden art.

Chapter II. General Histology

I 3. Cells. — Unity of Plan exhibited in Plants and Animals. Simple Cells. Adaptation to Different Offices. Modes of Multiplication.

7. Wherever we find the work of the Infinite, there we find Unity of Flan. Whatever the extent of the applications of this plan, whatever its modifications, there is still more or less apparent the distinct central idea. Amid the seemingly great diversity of substances in plants and animals, there appears a beautiful and remarkable exhibit of this Unity.

8. Protoplasm* is the formal basis of all living bodies. Animal Pro'to-plasm,, or Blas-tema, f as it is often called, is an albuminous fluid, generally regarded as identical with the liquor sanguinis, or fluid portion of the blood, in which the red corpuscles are suspended. Floating in this protoplasm are numerous minute spheroidal cells, and an infinitude of smaller bodies having the appearance of dots, called granules. From this organizable fluid every part of living beings is formed ; here is Unity of Substance.

9. The simple Nucleated cell is the earliest orga'Q.ic form of every living thing, and increase of size is but an increase of the number of cells. There are sundry very low animals, each of which is structurally a nucleated cell, a colorless blood-corpuscle, leading an independent life ; a step higher come those which are little more than aggregations of similar cells ; and at length, as the vital functions become more and more differentiated, appear those with cells variously modified, forming increasingly well-defined and complicated organs, till they seem to reach perfection in man.

* Gr., protos, finst, and plasma, formed. f Gr., hlastos, a germ.

10. In the plant-world we find the same plan pursued ; under the microscope, the vegetable and the animal cell appear essentially the same, but they are by no means identical. In examining the nucle'oli of animal cells, little circular bodies dart across the field of view. These seem to possess the power of voluntary movement ; and, had we the requisite refinement of sight, we should doubtless be able to classify even these minute bodies as accurately as we now do the fully-developed animal. In the vegetable cell these are never seen. It appears, then, that the lowest and the highest organism — the fungus and man — have, in their earliest development, a unity of form of which the type is the simple

cell.

Fig. 1.

1 2

Fig. 1. An Ideal Ckll. — 1, Cell, with its wall, protoplasm, nucleus and its nucleolus. 2, The same divided into two. 3, The same divided into four cells. 4, The same divided into many cells. The dark portion, the protoplasm; the white spot, the nucleus; the inner small circle, the nucleolus. Magnified.

11. A Simple Cell consists of a delicate sac containing protoplasm, in which is another very minute sac, called the nu'cleus, which contains yet another sac — the nucleolus or little nucleus. Very minute particles or granules are also seen. A good example of a simple animal cell on a large scale is an egg : the lining of the shell is the cell-wall or sac ; the white is the contained protoplasm ; the yolk is the nucleus; and its germ-spot is the nucleolus. (Figs. 1, 2.)

12. Cells in the course of their development are subject to numberless modifications — the animal cell, to subserve various purposes in the animal economy ; the vegetable cell, in the vegetable economy. As if under the immediate control of intelligence, they select each its own appropriate substance, rejecting all else. One set of cells has for its ofiice the production of motion ; another set is for the purpose of secre-

ANATOMY, PHYSIOLOGY AND HYGIENE.

tion ; anotlier, for assimilation ; another, for absorption ; still another, for reproduction ; and so on, through all the dissimilar offices of the animal economy,

13. Cells multiply in three ways : 1st, A cell may elongate, contracting in the middle like an hour-glass or dumb-bell, by the infolding of the cell-wall, till a complete division is made and two cells are formed, each with its own share of the original nucleus ; the new cells divide in a similar manner, and like divisions are repeated indefinitely ; 2d, Another form of multiplication is by the division of the nucleus vjithin the cell; each part appropriates a portion of the fluid, and at length vesicles are formed, the old cell-wall breaks, and the vesicles develop into perfect cells ; and 3d, Cells are sometimes developed de novo from the protoplasm, which contains nuclei and granules. (Figs. 1, 2, 3.)

Fig. 2. Process of Multiplication of Cells. — 1, Simple cartilage cell from the embryo. 2, Increase of cartilage cells by diyision of the primary cell. 3, 4, Groups of cartilage cells, from an adult articular cartilage. Magnified.

Fig. 3 exhibits Groups of Cartilage Cells imbedded in a homogeneous matrice, 1, Toward the exterior. 2. Toward the interior surface. Highly magnified.

14. Cells have their period of growth, of perfection and of decay. While the vital force directs and controls the chemical and mechanical agencies, they tend to preserve and build up the system ; but when the vital powers yield, they tend to its decay, and, ''as if they were the grave-diggers of Nature, fulfill the old motto — ' Earth to earth and dust to dust.' "

GENERAL HISTOLOGY.

I 3. Primary Tissues. —Fi&rows Tissue — Areolar— Cartilaginous- Adipose— Muscular—Sclerous— Tubular— Nervous.

15. By the various aggregations and transformations of cells the different tissues of the body are formed, and their individual characters depend upon the peculiar selecting power of these cells.

16. The Primary Tissues are reducible to the following : the Fi'brous, the Are'olar and the Cartilag'inous, which, collectively, form the Conned'ive tissues ; and the Ad'ipose, the Musc'ular, the Sck'rous, the Tulhular and the Ner'vous tissues.

Fig. 4. Fibrous Tissue. — 1, Portion of tendon, exhibiting its composition of prismatic bundles of fibrous tissue, the filaments all parallel to one another. 2, A few bundles drawn from the others, exhibiting their union by delicate crossing filaments of connective tissue. 3, One of the varieties of fibrous tissue. 4, A single bundle, more highly magnified, with a portion (5) of the filaments fretted out.

Fig. 5. Portion of Connective Tissue, from the axilla, exhibiting its composition of bundles and filaments of fibrous tissue crossing in every direction. The rounded bodies represent a single row and a portion of sm.all groups of fat cells. Magnified.

17. The Fibrous form of connective tissue is composed of minute filaments arranged in parallel and somewhat wavy bundles, marked with faint cross-waves. It is strong, unyielding and glistening. The fibrous tissue has two distinct forms — the White Fibrous and the Yellow Fibrous.

18. The White Fibrous tissue is formed of white, glistening, inelastic bands, having longitudinal creasings, but not admitting of separation into filaments of determinate size. This tissue, by long boiling, is entirely resolved into Gel'atine,

The white fibrous tissue is found under three forms : Mem'- brane,"^ Lig'amentf and Ten' don. "l

19. The Yellow Fibrous tissue is composed of yellow elastic bands separable into their component filaments. It is called the Elas'tie tissue, elasticity being its chief characteristic. It does not gelatinize by boiling. It is found in the middle coat of the arteries, in the vocal cords, between the vertebrae, and in many other places where elasticity is needed. (Figs. 4, 5.)

Observation. — In rhenmatism the connective white fibrous tissue is the part chiefly affected; hence, the large joints and the loins, where this tissue is most abundant, sufler most. Where there is predisposition to rheumatism, the tendency to it may be lessened and attacks relieved by increasing the amount of clothing over the part affected.

20. The Areolar form of connective tissue consists of bands of the fibrous, both of the white and yellow, which interweave in every direction, leaving open spaces between, called cells; hence this tissue is sometimes called Cel'lular. These spaces communicate through the body, and contain a fluid resembling the serum of the blood. Although the connective areolar tissue enters into the composition of all organs, it never loses its individuality. In the nerves and muscles it shares neither the sensibility of the one nor the contractility of the other. (Figs. 5, 6.)

Observation. — The swelling of the feet so often seen in feeble persons shows the peculiarity of this tissue, which allows the fluid to pass from part to part and accumulate in the lowest portion of the body, while a recumbent position restores the original shape. Great excess of the fluid produces general dropsy. The free communication between all parts of this tissue is still more remarkable in regard to air. Sometimes, when an accidental opening has been made fi'om the air-cells of the lungs into the adjacent tissue, the air in respiration penetrates every part of the surrounding tissue, and even of the entire body, till inflation endangers life from suffocation. Butchers often avail themselves of this fact, inflating their meat to give it a fat appearance.

21. Cartilaginous tissue consists of a solid mat'rice, ap-

* Lat., membrana, a web. f Lat., ligo, to tie or bind.

% Gr., teino^ to stretch.

GEI^^EEAL HISTOLOGY.

parently homogeneous in structure, resembling ground glass. In this are imbedded nucleated cells, sometimes arranged simply, but usually in groups. It has no perceptible nerves nor blood-vessels. Cartilage is elastic and flexible, but inextensible — qualities admirably essential to its use in the formation of the joints and in giving to other organs form and strength without too much rigidity. This tissue constitutes the articular cartilages, the cartilage of the ribs, of the larynx (except the epiglottis), of the trachea and its divisions, and of the nose. The bones usually originate in cartilage, which disappears as bony matter is deposited ; such cartilage is called temporary, while that which continues till later years is called permanent. (Fig. 3.)

Fig. 6. Adipose Tissue, with groups of fat vescicles contained in the meshes of ( onnective tissue.

Fig. 7. Muscular Tissue.— 1, Two portions of a muscular fasciculus. 2, Cut extremities of the fibres, showing their prismatic form. 3, Delicate sheath, composed of obliquelycrossing filaments of fibrous tissue. 4, The fibres of the commencing tendons. Partly a diagram.

22. Adipose tissue has the peculiarity of not being essential to the constitution of any organ. It is composed of delicate aggregated cells of nearly spheroidal form, containing a

ANATOMY, PHYSIOLOGY AND HYGIENE.

substance called fat. It is found in the interspaces of areolar tissue beneath the skin, and also around the heart and kidneys, while none is ever found within the skull, the lungs and the eyelids, where its presence would interfere with their several ftinctions. Fat accumulates more readily than other matter, and is the earliest removed in disease. It is a storehouse of nutriment always ready for use and a non-conductor of heat; it also gives roundness and beauty to the form.

Fig. 8 (Wagner). A Piece of the Web of a Frog's Foot, showing the fine capillary network connecting the termination of the arteries with the commencement of the veins.

Fig. 9 (Allen Thomson). Minute Piece of tde Margin of the Frog's Web, showing the ultimate capillaries, connecting the end of a small artery with the beginning of a minute vein. The oval blood-corpuscles, with nuclei, are seen in these vessels, and the arrows entering and passing out of the artery and vein indicate the course of the bloodcurrent. Magnified about thirty diameters.

23. Muscular tissue is composed of fibres, which are themselves composed of minute fibres, called flhrillce or filaments. This tissue has for its peculiar characteristic contradility, and is the instrument upon which the sensible motions of the body depend. It is a good conductor of electricity, and very sensitive to that agent. It has within itself constant electrical currents, called, collectively, the muscular current. (Fig. 7.)

24. Sclerous tissue is found in the bones and teeth. Its composition and arrangement vary at difierent periods of life.

25. Tubular tissue consists of a network of minute tubes,

GENERAL HISTOLOGY.

called cap'illary'^ vessels. These vessels connect the terminal extremities of the arteries with the commencement of the veins, but are otherwise closed, and never communicate except by imbibition with the structures through which they pass. Their walls are composed of exceedingly thin, transparent, structureless membrane containing scattered nuclei. They vary in size, being largest in the bones and smallest in the brain and in the lungs. This tissue is found in all parts of the body, excepting the substance of the teeth, the cartilage of the joints, the transparent part of the eye, the epitlie'lial tissue, the hair and the nails, (Figs. 8, 9.)

26. The Neevous tissue is distinguished from all other tissues by its sermhility. Like the muscular tissue, it has constant electrical currents. It forms the essential substance of the brain, spinal cord and nerves. This tissue contains three distinct microscopical elements — Nerve- Cells or Ganglionie Corpuscles; and White or Tubular fibres.

27. The Ganglionic Corpuscles are cell-bodies containing pulpy matter, with one or more nuclei surrounding colored granules. These cells vary in shape, being roundish, pear-shaped or branched in a caudate or stellate manner, these offsets being continuous with the cell-wall and its contents, and often entering another cell and connecting the two. These nerve-cells are found in the brain, spinal cord

Fig. 10 (Kolliker and Hannover). 1, Nucleated cells from a sympathetic ganglion. 2, Branched or stellate cells from the gray substance of the spinal cord. 3, Branched cells from the medulla oblongata. 4, Simple and branched cells from the convolutions of the brain. 5, A large cell from the gray substance of the brain. Magnified one hundred diameters.

Gray or Gelatinous fibres;

* Lat., capillus, a hair.

and ganglia, and at the extremities of the nerves of sight and hearing. (Fig. 10.)

28. The Gray or Gelatinous fibres are soft and granular, with no distinct medullary sheath. They contain many dark nuclei, and are most abundant in the sympathetic ganglia and its branches.

29. The White or Tubular fibres are microscopic tubes. The walls are structureless membrane enclosing a layer of medullated matter resembling fluid fat, which acts as a sheath ; within this is a firmer part or core, called the band-axis or axis cylinder : this is albuminous.

The gray substance is most abundant in the outer part of the brain, and the white in the inner ; but the two intermix more or less in every part of the nervous system.

^ 4. Membranes. — Basement Membrane. Epithelium. Serous Membrane. Synovial Membrane.

30. Basement Membrane is an exceedingly thin, delicate, structureless layer of protoplasm or blastema, resembling, under the microscope, a film of transparent gelatine. Upon it, in various parts of the body, are imbedded minute epithelial cells. The membrane formed by these cells is called epithe' lium.'^ The relation of this structureless membrane to the epithelium gives it the name of Basement

Membrane.

Fig. II.

Fig. 11. Diagram Exiii..ii..'.u lUi, iulative Position of the Common Anatomical Elements of Serous and Mucous Membranes, the Glands, the Lungs and the Skin. —1, Epithelinm, secreting cells or epidermis, composed of nucleated cells. 2, Basement layer. 3, Fibrous layer, in which the arteries and veins (4) terminate in a capillary network. Magnified.

31. From difierence in form and other peculiarities, the

* Gr., epi, upon, and thele, a nipple.

Epithelium is divided into several varieties — as the Squamous Epithelium, consisting of several layers of thin scales, which are flattened cells having a nucleus and a few scattered granules, as in the mucous membrane of the mouth ; the Pavement Epithelium, consisting of from one to four layers of nucleated cells, six-sided and regularly arranged like the blocks of a pavement (whence the name), as in the serous membranes ; the Columnar Epithelium, consisting of a single layer of six-sided columnar cells, with a conical pro-

FiG. 12, Squamous Epithelium, consisting of nucleated cells transformed into broad scales, from the mucous membrane of the mouth. Highly magnified.

Fig. 13. Pavement Epithelium, from a serous membrane, highly magnified, and seen to consist of flat, six-sided nucleated cells.

longation terminating in a progeny of developing cells, as in the mucous membrane of the stomach and intestines; the Ciliated Epithelium, having cells possessing at their free extremity fine filamentary processes of the cell-wall resembling the eye-lashes (whence the name). During life these cilia are endowed with a power of moving rapidly backward and forward in a wave-like manner, reminding one of the movement of a field of grain swept by a gentle breeze. Currents are thus produced in liquids, conveying them from one part to another. This kind of epithelium is found on the mucous membrane of the upper part of the nose and pharynx, the Eustachian tube and all the respiratory organs. (Figs. 12, 13, 14, 15.)

32. Beneath the basement membrane and in contact with it is a very dense and vascular layer of areolar and elastic tissue. This triple arrangement of epithelium, basement membrane and fibro-areolar tissue constitutes the serous, the synovial and the mucous membranes, the skin, the ducts of all glands, and the inner coat of the blood-vessels and the lymphatics. (Fig. 11.)

33. The Serous Membrane is that portion which lines the walls of certain closed cavities or sacs. It is smooth, shining and moistened by a fluid called se'rum, which the membrane secretes ; as the pleu'ra, peritone'um, pericar'dium, arach'noid, etc. (Fig. 16.)

Fig. 14. Diagram of a Vertical Section of the Mucous Membrane of the Small Intestines. Highly magnified. — 1, Fibrous layer, in which the blood-vessels are distributed. 2, Basement membrane. 3, Young nucleated cells. 4, Layer of columnar cells. 5, 6, Cells in the act of being shed or thrown off. 7, Free ends of the columnar cells, exhibiting their six-sided form. 8, A single columnar cell, exhibiting its actual form at all parts.

Fig. 15. Diagram of a Vertical Section of the Bronchial Mucous Membrane. — 1, Columnar ciliated epithelial cells. 2, Cilia. 3, Nuclei. 4, Young cells. 5, Basement membrane. 6, Fibrous layer.

34. The Synovial Membrane resembles the serous very closely as regards structure and the closed sacs. It also secretes a fluid called syno'via, which is more viscid than that of the serous membrane. It has fringe-like processes hanging loosely in the joints having large epithelial cells, which probably secrete the synovial fluid. This membrane covers the cartilages, and lines the ligaments which enter into the composition of the joints.

Observation. — When the synovial membrane is ruptured, the synovia escapes into the surrounding areolar tissue, and what is popularly known as the "weeping sinew" is formed. Similar tumors in the joints of lower animals are called " windgalls."

GENERAL HISTOLOGY.

35. There are two Mucous IMembranes — the Gastro-Pulmonary and the Urinary. These do not form closed sacs, like the serous and synovial membranes, but both open to the surface. The mucous membranes secrete a viscid fluid, called mucus, and in their glandular recesses are formed various secretions, as saliva, bile, tears, etc. These membranes vary in different parts both in thickness and appearance. In the nasal and air passages the membrane is smooth, ridgy in the stomach, papillous in the tongue and villous in the intestines.

Fig. 16. Diagram EXuiBnixG the Relation of a Serous Membrane (the pUura) to THE Organ it Invests and the Cavity it Lines. — 1, Lung. 2, Eoot of the lung, which is the only attached portion of the organ. 3, Side of the thorax. 4. Diaphragm. 5, Parietal pleura, 6, Pulmonary or reflected pleura. 7, Cavity of the pleura.

Fig. 17. Mucous Membrane from the Jejunum. — 1, Tilli resemhliug valvulse conuiventes (folds of lining mucous memhraue) in miniature. 2, Tubular glands: their orifices. 3, Opening on the free surface of the mucous membrane. 4, Fibrous tissue. Magnified.

36. The Gastro-Pulmoxary Mucous membrane commences at the mouth, enters the nostrils, passes between the eyelids, dips into the deep parts of the ear, lines the trachea and the air-tubes of the lungs, and the alimentary canal from one extremity to the other.

37. The Urixary Mucous membrane lines the ducts connecting the kidneys and the bladder, of which it forms the interior coat ; also the passages to the skin, which integument is continuous with the mucous membranes.

Chapter III. General Chemistry

^ 5. Solids and Fluids. — Proximate Constituents — Inorganic — Organic — Nitrogenous — Non-Nitrogenous. Ultimate Chemical Elements.

38. The human body is composed of solids and fluids, reducible, by chemical analysis, to the same constituents and elements. In different periods of life the proportion of fluids and solids varies ; the former being more abundant in youth than in old age. This is one reason why the limbs in childhood are soft and smooth, but in later years hard and wrinkled.

39. If the tissues of the body are subjected to chemical analysis, they yield about ninety substances, called Proximate Constituents, these being the first chemical compounds into which the tissues resolve themselves. In living beings vitality is, as it were, "the architect who plans the building and sees that the requisite materials are procured by the chemical processes and Avorked up according to his will." Hereupon arises many new substances which cannot be artificially imitated ; these are called Organic proximate constituents. Those substances found in the inorganic kingdom also, and capable of artificial imitation, are called Inorganic proximate constituents.

40. Of the Inorganic Proximate Constituents, water is the most abundant : it exists in all the tissues ; next to this, in relative quantities, are Phosphates of Lime, of Hague' sia, of Soda and of Potas'sa ; Carbonates of Lime, of Soda and of Potassa; Chloride of Sodium (common Salt) and of Potassium ; and Fluoride of Cal'cium. Some compounds contain Iron, Sil'ica, Manganese', and perhaps some accidental substances, as Lead, Copper and Alu'minum. Ammo'niay in

GENERAL CHEMISTRY. 27

combination, is found in the urine. Ox' y gen, Ni'trogen and Carbonic Acid gas exist in a free state.

41. The Organic Proximate Constituents are of two classes. One class contains the chemical element ^zo^e' * or nitrogen ; hence its compounds are called azotized or nitrogenous; the other has no azote, and its compounds are named non-azotized or non-nitrogenous.

42. The Nitrogenous cL'ss contains Alhu'men'\ and its allied substances, called Albuminoids. Some of the most important are — Alhu'minose, Fibrin, Mus'culin, Glob'ulin, Hcdm'atin, Ca'sein, Cartila' gin, Sal'ivin, Pep'sin, Pancrea'tin, Mu'cin, Neu'rin, Ker'atin, Elas'tin, Mela'nin and Biliverd'in; also some acids, as the Cer'ebric, Chol'ic and Uric.

43. Albumen and the albuminoids, together with fatty matter (non-nitrogenous), are the great nutritive substances of the animal economy. Albumen is well known in the white of an egg, whence its name. It is found in the substance of the brain and nerves ; in the fluid part of the blood ; in the moisture that pervades the muscles and other tissues ; in the lymph and chyle; and in the mucous, serous and synovial secretions. It coagulates by the action of heat and alcohol, and is dissolved by weak acids and alkalies.