ALBERT R. MANN LIBRARY New York State Colleges of Agriculture and Home Economics AT Cornell University Gift from the CLIVE M. McCAY LIBRARY OF Nutrition and Gerontology Cornell University Library QP 34.D76 A text-book on anatomy, physiology, and 3 1924 003 131 301 Cornell University Library The original of tiiis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31 9240031 31 301 YEAR PUBLR PLACE 88691 Mid IgrfiitKm* **'*• EDITION liKroMr »iid Bn>tli«r» DATE PROF. 5/21/65 SUB. TYPE TO BE KEPT IN FUND D D D THIS PUBLICATION, JUST ACOUIRED", MAY INTEREST YOU. THIS PUBLICATION. WHICH YOU RECOMMENDED. HAS BEEN RECEIVED. IF NEEDED. PRESENT THIS SLIP AT LOAN DESK. THIS CONFIRMS YOUR ORDER FOR THIS PUBLICATION. TEXT-BOOK ON AMTOIY, PHYSIOLOGY, and HYGIENE. FOR THE USE OF SCHOOLS AND FAMILIES. By JOHN C<*1)RAPER, M.D., PEOFESeOB OF KATCBAL HIBTOBY AND PHYSIOLOGY IN THE OOLLEQE OP THE OITT OF NEW YOBE^ OF ANALYTICAL OHEMIBTEY IN THE UNIVEB8ITY OF NEW YOBK, AND OF OHBM- ISTBY IN THE UN1VEE51TY MEDICAL OOLLEGE.- SSIitj^ ®ne f^unUteU anti Sebents SUustrations. NEW YORK: HARPER & BBOTHEES, PUBLISHEES, FRANKLIN SqUABE. 186 6. 352506 Entered, according to Act of Congress, in the year one thousand eight hundred and sixty-six by Harpek & Bkothebs, In the Clerk's Office of the District Court of the Southern District of New York. PREFACE. Having been engaged for many years in lecturing upon the various branches of Natural History, and having experienced the difficulty that exists in attempting to teach Anatomy and Physiology without a text-book adapted to the wants of col- legiate classes, I have ventured to publish my course of lec- tures on these subjects in the form herein presented, that the students of the College of the City of New York may have every opportunity of perfecting themselves in these branches as thoroughly as the limited time devoted to them will permit. Although the chief object has been to prepare a text-book for academic students, the work is also designed for the use of schools and families ; and students of medicine will find that it contains a few hints of value to them, especially in Lecture XXVH., which has been added for their benefit. The division of Hygiene will be found to present many facts of interest to the general reader ; and, in view of the measured but apparently inevitable approach of cholera to our shores, we have in the last lecture given a short summary of the means by which we may hope to avoid its attack. Anatomy and Physiology have been subjects of study for many centuries, and there is but little that an author can say regarding them that is novel or original, I would therefore call attention to the results of the experiments on urea, and to the conclusions dravm from them, and acknowledge my indebt- edness to the works of Carpenter, Cruveilhier, Marshall, Dun- glison, Bowman, Draper, and many other men of science, whose labors and writings are quoted, aud whose opinions have been adopted. IV PBEFAOB. Finally, to the Board of Education of the City of New York I would express my sincere thanks -for the liberal manner in which they have enlarged the ordinary collegiate course by in- grafting on it the study of modern sciences, and enabling the young men who graduate from the College bf the City of New York to obtain a knowledge of the construction and workings of the human system, which is by all considered to be a necessary part of a liberal education. COLLBeE or THE ClTY OF New Yokk, Nov, 30, 1865. CONTENTS. FIRST DIVISION. ANATOMY AND STATICAL PHYSIOLOGY. LECTURE L INTBODUCTION. Theories regarding the Nature of Life. — The Food introduced into the System is combustible. — The Substances voided from the Body are all burnt or oxidized. — The Methods to be employed .in the Examination of the Structure and Function of Organisms endowed with Life. — GeUs enter into the Composition of all Tissues and Creatures . . . Page 1 LECTURE IL CELLS. Parts composing a Cell. — Vegetable and Animal CeUs. — All living Things originate in and are composed of CeUs. — Reproduction of Cells. — For- mation of Tissues from Cells. — -Secreting and protecting Cells. — Cells enter into the Composition of Liquids. ^JViitrition of CeUs. — Definitions of Anatomy, Physiology, and Hygiene 3 LECTURE III. AU-ATOMY or THE HITMAN BODY. The Tissues and Fluids composing the Body. — Divisions of the Body. — Cavities of the Head, their Contents. — Cavities of the Tnmk and their Contents. — Subdivisions of the Fxtremities. — The Skeleton, its Uses. — Composition of Bone, and variations in the Proportions of its Ingredi- ents.-^ Diseases of Bdne.^ Importance of Bones in certain Manufac- tures. — Microscopic Appearance of Bone. — Membranes of Bone. — Di- vision and Classification of Bones 7 LECTURE IV. BONES COMPOSING THE SKELETON. Number of Bones in the Body. — Bones of the Trimh. — Pelvic Bones . 15 LECTURE V. THE SKELETON — Continued. Bones of the Upper Extremity. — Bones of the Lower Extremity. — Varie- ties of Joints. — Tissues which enter into the Composition of Joints. — Joints and Bones form Levers. — Diseases and Wounds of Joints . 21 VT. OOWTEIfTS. . LECTURE VI. THE MUSCULAR SYSTEM. The Muscular Tissue. — Microscopic Characters of voluntary and involun- tary Muscle Cells. — Tendons and their Position. — Divisions of Muscles. — Muscles of the Head and Neck. — Of the Upper Matremities. — Of the Trunk. — Of th& Lower Extremities Page 25 LECTURE VIL ORGANS OF NUTEinON. Divisions of the Nut/ritive Process. — Divisions of the Digestive Appa- ratus. — Distinctive Characters of Mucous and Serous Membranes. — The Composition and Classification of the Teeth. — Description of the Buccal Cavity. — The Pharynx. — The (Esophagus. — The Stomach. — The four Serous MeMranes. — The Mucous Coat of the Stom,ach. — The FoUicles of the Stomach. — The Ends of the Stomach 34 LECTURE VIII. OEGANS OF NUTKiTiON — Continued. Divisions of the smaM Intestine. — Coats of the Intestine. — Movements of the Infpstine. — Valvidce Conniventes.-— Villi, their Composition,. — Divi- sions of the large Intestine. — Appendix Vermiformis 41 LECTURE IX. OEGANS OF NUTRITION — Continued. Duccal Glands. — Description of the Salivas. — Properties of mixed Saliva. — Natwre of Ferments. — Abdominal Glands. — Duty of the Diver. — JVa- ture and Properties of Bile. — The Pancreas. — Nature and Properties of its Secretion. — Origin and Properties of Gastric Juice. — Uses of Pep- sin. — Origin and Properties of Intestinal Juices 45 LECTURE X. FOOD. Annual Ammint of Food consumed. — The Ingesta. — The Introduction and Use of Water in the Systefn. — latent Seat of Vapor of Water. — Variation in the Food of different Nations 49 LECTURE XL DIVISIONS OF FOOD. Milk, its Composition and Variations. — The nitrogenised Grroup. — 2%e non-nitrogenized Group. — Hyd/ro-carhons. — Carbo-hydrates. — Fermenta- tion of Starch and Sugar. — Influence of Temperature on Fermentation. — Composition of Flour. — Bread-making. — Wine-making. — Use of Phosphate of Lime. — Of Chloride of Sodiwn 51 LECTURE Xn. DIGESTION. Mastication. — Action of Saliva. — Action of Gastric Juice. — Formation and Properties of Chyme and Chyle. — Action of Pancreatic Juice on CONTENTS. VU Hydro-carbons and Gario-hydrates. — Old and new Theories of Diges- tion. — Digestibility of various Articles of Food. — Effect of Quantity on the Rate of Digestion. — Indigestion as a Disease and a Symptom. — Ef-^ feet of Nature of Diet on Length of Intestine. — Digestive Apparatus in certain Animals Page 56 LECTUEE XIII. CAPILLAET ATTEACTION AND ENDOSMOSIS. Composition ofMeces. — Origin and Diurnal Amount of Fmces. — Intes- tinal Gases. — GapUlary Attraction. — Examples and Explanation of GapiUary Attraction. — Dialysis. — The Endosmometer. — Endosmosis.—^ Exosmosis. — Action of Crum in the Endosmometer 62 LECTURE XIV. ABSOEPTION. Mechanism of Absorption in Plants. — Functions of the various Pa/rts, — The ascending Sap. — Hie Force it exerts. — Descending Sap. — Descrip- tion of a Villus. — Dacteals. — Reeeptaculum Ghyli. — -Thoracic Duct. — Stomach Absorption. — YiUus or Intestinal Absorption. — Action of Mes- enteric Glands. — Effect of Disease of Mesenteric Glands .... 66 LECTURE XV. ^ BLOOD. Properties of Sap. — Of Blood. — Variations in the Appearance of Blood. — Gomposition of Blood. — Influence of Sex and Glimate on its Gomposi- tion. — Function of Water. — Of Albumen. — Of Extractive. — Of Fats. — Of Salts. — Of Fibrin. — TJie Clot. — Action of Mesenteric and Lymphat- ic Glands. — Med Blood Discs. — White Discs. — Hmmatin. — Globulin. — Plasma. — S&rum 70, LECTURE XVL THE BLOOD-VESSELS. The Divisions of Blood-vessels. — Their Composition and Character. — Or- der of Development of the Blood System. — The Heart described. — The Pericardium and Ekdocardium. — Muscular Tissue of the Heart. — Its Cavities, their relative Position. — Bate of Pulsation. — Valves. — Thsir Function.- — Valvular Sounds. — Diseases of the Valves 76 LECTURE XVII. THE BLOOD-TESSBLS — Continued. Pulmonary and Systemic Blood-vessels. — Course of the Pulmonary Ves- sels. — 77ie Aorta. — Its Divisions. — Its Termination. — The Cardiac Ar- tery. — Arteria Innominata. — Common Carotid. — Subclavian. — Arteries of the Upper Extremity. — 7%e Intercostal Arteries. — The Phrenic. — Cos- liacAxis. — Superior Mesenteric. — Other Abdominal Arteries . . 82 LECTURE XVIIL THE BLOOD-VESSELS — Continued. Common Iliac Arteries. — Internal Iliacs. — External Iliacs. — Arteries of the Lower Extremities. — Veins of the Head. — Of the Upper Extremity. VIU CONTENTS. — The great Veins of the Chest. — Veins of the Lower Extremities. — Por- talVein.— The Course of the Blood Page 89 LECTURE XIX. CIECCLATION OF THE BLOOD. Harvey's and Draper'' s Theories. — Affinity of Liquids for Tubes. — Princi- ple of Venturi. — Causes of the Circulation in Systemic and Pulmonary Vessels differ.— Perfection of Draper's Theory. — Course of various Ar- ticles to different Parts of the Body 92 LECTURE XX. SBCEBTION AND EXCEETION. Formation of Secretions. — Structure of Glands. — Action of Spheroidal Cells. — Filtration. — The Mammary Gland. — Its Changes and Diseases. — Colostrum. — Organs of Mecretion. — -The Shin. — Composition and Function of the Skin. — Its Appendages. — Its Glands. — Their Func- tions 99 LECTURE XXL INSENSIBLE PBBSPIBATION. Methods for determining its Quantity. — Diurnal and nocturnal Loss com- pared. — The Effect of Exercise.— The Substances produced by the Disin- tegration of Muscle when in Action escape by the Skin, and not by the Midneys. — JRelation of sensible and insensible Loss to each other. — Ef- fect of Ingestion of Food on insensible Loss. — Diurnal Variation in the Weight of the Body 104 LECTURE XXII. EESPIEATION. Divisions of the Respiratory Apparalus.-^The Larynx. — The Trachea. — The Bronchi. — Tlie Air-cdls. — The, Lungs. — T%e Divisions and Mem- branes of the Lungs. — Raie of Respiration. — Action of the Lungs. — Stages of Inspiration. — Diffusion of Gases. — Influence of Membranes on Difusion 118 LECTURE XXIII. EESPIEATION — Continued. Second and third Stages depend on Diffusion of Gases. — Stages of Expira- tion. — Difference between inspired and expired Air. — Easperiments on Respiration. — Object of Respiration. — Diseases affecting the Respiratory System 125 LECTURE XXIV. ANIMAL HEAT. D^nition of Animal Heat. — Paine' s Experiments on the Temperature of Plants. — Cold and hot blooded Animals. — Relation of tlie Nervous Sys- tem to the Production of Heat. — AUotropio Condition of Carbon and other Elementary Substances. — Blushing explained. — Variations in the Temperature of the Body. — Temperatures that can be endv/red by the Body 131 CONTENTS, IX LECTURE XXV. , THE UEINAEY SYSTEM. Position 'and Descriptive Anatomy of the Organs forming the Urinary System. — Microscopic Anatomy of the Kidney. — Portal 'Cir mal ? Illustrate the parts of a cell by those of an egg ? How are cells reproduced ? TISSUES ARE COMPOSED OF CELLS. Fig. 4. Pig. 5. Eeproduction of Cells by Granulation. to give the cell a dumb-bell form, which becomes by degrees more and more complete, until it is finally divided through the nucleus and two perfect cells produced. In reproduction by granulation the movement commences in the nucleus. It breaks up into exceedingly minute grains, which form nucleoli, that gradually enlarge until they fiU the nucleus, which soon disap- pears, and the cell seems to be filled with nuclei. The wall then bursts, and the nuclei, being set free, become new, perfect cells. In order to form tissues, cells are sometimes arranged as in Fig. 5, presenting an appearance simi- lar to that of a wall built of cut stone. Such are called mural tis- sues. Sometimes cells are elon- gated and placed end to end, as in the fibres of the yeast plant and conferva. In other instances the cells become greatly elonga- Fig. 6. Mural Tissue. Varieties ot Conferva showing the shape of the Cells and Nuclei. Describe reproduction by section and granulation. How do cells form tissues ? b DIVISIONS OF PHYSIOLOGY. ted, as in in voluntary muscle and fibrous tissues. K tlie cells retain their spherical figure the ^' ' organs formed produce secretions, wnile in the skin and all structures intended merely for protection, they dry up and become scale-like. Not only are tissues composed of cells, but all animal fluids, as for example blood, contain one or more special forms of cells by which we can often detect their presence. The description of these, as well as of the cells of special ^ „ ^^ ^. tissues, as muscle and nerve, must Yellow fibrous Tissue. , ' _ .- i ,t !• be reserved untu we reach the dis- cussion of such fluids and organs. In order that a simple organism like a cell shall exist and grow, it must be supplied with proper nutriment. The tissues of men and animals, being formed of cells, must therefore be famished with the materials required for their growth and development. To satisfy the stem flecessity that Nature has thus impressed on all animals, that they should seek their food, she has merci- fully provided them with bodies constructed in such a manner as to be capable of motion, and possess the power of convert- ing various articles of food into a nutritious fluid, on which tis- sues may feed. The study of the body is divided into two distinct branches, Anatomy and Physiolegy. The first deals with its structure ; the second treats of the functions of the organs of which it is composed. To these we may add a third, Hygiene, which ex- amines into the conditions most favorable for the maintenance of perfect health. Physiology is, by Professor J. W. Draper, divided into Static and Dynamic Physiology. The first relates to man as an indi- vidual, and discusses the functions of the different organs of the body. The second treats of man in his social state, and deals with nations or masses of men, examining into their rise, progress, and influence on each other. The advantages attend- ing this division are so self-evident that we shall adopt it without discussion. What is the difference between a secreting^and a protecting, cell? Into what branches is the study of the body divided? What is Anatomy? What is Physiology? What is Hy- giene ? What are the divisions of Physiology ? TISSUES AND OEGAJSTS OP THE BODY. 7 In describing the various organs of tlie body, we shall first explain the anatomical structure of each, and then pass to the consideration of its function, so that the structure and function may be connected with each other in the miad of the student, and more readily recollected. LECTUEE III! ANATOMY OP THE HUMAN BODY. The Tissues and Fluids composing the Body. — Divisions of the Body. — Cavities of the Head, their Contents. — Cavities of the Trunk and their. Contents. — Subdivisions of the Metremities. — The Skeleton, its Uses. — Composition of Bone, and variations in the Proportions of its Ingredi- ents. — Diseases of Bone. — Importance of Bones in certain Manufac- tures. — Microscopic Appearance of Bone. — Membranes of Bone. — Di- vision and Classification of Bones. The body is composed of solid tissues or organs, and fluids. They are, 1st. Bone, which supports the other tissues and organs, and gives a fixed figure and form. 2d. Ligament and cartilage connect the bones and form a skeleton, possessed of joints and capable of motion. 3d. Muscle, endowed with the property of contractility, gives motion to the body. 4th. Organs of nutrition, divided into digestive, absorptive, and circulatory. 5th. Organs of secretion and excretion, as the lungs and kid- neys. 6th. Nervous tissue regulates the action of the muscles and all the organs of the body. 7th. Special senses — vision, hearing, smell, taste, and touch — by which the system is brought in comftiunication with exter- nal objects. . 8th, Areolar or connective tissue. 9th. The skin and its appendages. 10th. The organs of reproduction. The fluids of the system are, Ist. Blood, which may be arterial or venous. The first is bright red, owing to its containing oxygen ; while venous blood is dark blue, and contains carbonic acid. What are the tissues of the body? What are the uses of hone? of ligament and carti- lage ? of muscle ? What are the organs of nutrition ? Give examples of the organs of ex- cretion. What is the function of nervous tissue ? Name the special senses. What are the fluids of the body ? What is the difference between arterial and venous blood ? 8 FLUIDS OF THE BODY. 2d. Chyme and chyh. The first is a tawny yellow color, and formed during digestion in the stomach. The second is milky, and is found m the small intestines and lacteals; 3d. Lym/ph, a colorless fluid, contained in minute vessels call- ed lymphatics. It represents the excess of nutriment conveyed to various parts of the body. 4th. Bile, a yellow or greenish fluid secreted by the liver. It sometimes becom^es condensed, and forms hard masses called gall-stone% which cause excruciating pain as they pass into the mtestine. - > ;„./■-■'• 5th. Digestive juices, consisting of saliva, gastric, pancreatic, and intestinal juices. 6th. MocreUons and secretions, such as urine, sweat, milk. For the sake of convenience, the body is described under six divisions — ^head, trunk, and four extremities. The head contains the following cavities : 1st. The cranial, which accommodates the brain ; 2d. The buccal, in which the tongue and teeth are placed ; 3d and 4th. The orbital, contain- ing the eyes ; and, 5th. The nasal, inclosing the organ of smell. The trunk is divided into three cavities : 1st. The thoracic, which has yielding bony walls, and contains the heart, lungs, great blood-vessels, and air-tubes ; 2d. The abdominal, sur- rounded by soft, yielding muscular walls, and separated from the thoracic by a muscle called the diaphragm. The abdominal cavity contains the liver, which lies immedi- ately un4er th^ diaphragm, and chiefly on the right side; the stom,ach^ under'xl&e liver and on the left side ; the spleen, on the left of the stomach ; the kidneys, in the back of the cavity ; the intestines, in front and on the sides ; the pancreas, beneath and behind the stomach. The pelvic cavity, inclosed by unyielding bony walls, con- tains the bladder in the male, and the bladder and uterus ia the female. The extremities are divided into the upper and lower. The ' subdivisions of the upper extremities are the shoulder, arm, forearm, and hand. Those of the lower extremity are the hip, thigh, leg, and foot. With these preliminary remarks regarding the general char- What is the difference between chyme and chyle, and where are they found? What is lymph, and in what vessels is it found? What is bile? How are gall-stones formed? What are the digestive juices? What are the divisions of the body? What cavities are found in the head ? What do they contain ? Name the cavities in the trunk. What are the contents of the thoracic — of the abdominal— of the pelvic cavity? What are the subdi- visions of the upper extremity ? of the lower extremity ? FUNCTION OP THE SKELETON. 9 acters of the tissues and fluids of tlie body, we now pass to the study of THE SKELETON. All animals are provided with a more or less perfect skele- ton, the object of which is to furnish a support for the various soft tissues and organs, or to protect them from injury and vio- lence. In the lower orders it is often placed on the outside of the body, and is the only protection the creature has against the attacks of its numerous enemies. An excellent illustration of this arrangement is afforded by the oyster, which is furnish- ed with a hard shell or exterior skeleton, the chief use of which is to protect the soft tissues from injury. Passing a little higher in the scale, we find that the lobster and such creatures are endowed with a far greater freedom of motion than the oyster ; consequently, though their skeletons are on the outside of the body, they are built on a different plan ; the various parts are lighter, and arranged so as to fur- nish a system of jointed levers and supports, by which the creature can at its will transport itself from one place to anoth- er, and avoid its enemies, or obtain the food necessary for its proper nourishment. Though a certain degree of facility of motion can be reached by means of an exterior skeleton, yet it is almost incompatible with such perfect freedom as is required in the higher animals ; consequently we find that in fishes, reptUes, birds, and beasts,' the skeleton is in the interior of the body. It is every where covered by soft tissues, and is arranged so as to furnish levers for the organs of locomotion, 'or form cavities in which the more delicate organs, as the brain, heart, lungs, and digestive apparatus, may be properly protected from injuiy. In man and animals, the separate pieces of which the skele- ton is composed are called hones. These differ in their form so as to fulfill the purposes for which they are intended, but in chemical composition they show but slight variation. Analysis of Sam. S^^^!!!!"::::::::::;::;::::::::;:: '^IS ^nimai or organic 33.30 Phosphate oflime 51.04 Carbonate oflime 11.30 Eluoride of calcium 2.00 Phosphate of magnesia 1.16 Soda salts 1-20 Mineral or inorganic... 66.70 100.00 100.00 What is the object of the skeleton? Is it always placed in the interior of the body? What are its uses in the higher animals? What are bpnes? What is the chemical compo- sition of bone? 10 CHEMICAL COIVIPOSITION OP BOKE. Examining tlie above analysis by Berzelius, We find that we may regard bone as being composed of animal and mineral substances in the proportion of one third of the former to about two thirds of the latter. This, although true in regard to bones of adults, is not the case in children and old people. In the former the proportion of animal material is far greater than one third, and consequently in infancy and early child- hood the bones of the lower extremities are apt to bend if they are used too soon, since they are not sufficiently consolidated to support the weight of the body. The age at which they may with safety be used depends to a great extent on the diet and digestive powers of the child. If the food is not nutri- tious, or the constitution of the infant is poor, the proportion of animal material in the bones will be too great, and they will be flexible and bend, producing the deformity called rickets or bandy-legs, in which not only the bones of the legs, but also the ribs and pelvic bones, may be deformed to such an extent as to interfere seriously with the proper performance of the functions of the body. In the osseous tissues of old people, on the contrary, the pro- portion of mineral matter is in excess ; consequently their bones are very brittle, and break readily, often being fractured by such slight violence as making a false step while walking. Not only does age affect the composition of bone, but some bones always contain a greater proportion of mineral substance than others. For example, that in which the organ of hear- ing is situated possesses such a large proportion of inorganic substance as to have received the name of thepe^'ous, or stone- like bone. With" these exceptions, we may regard bone as having a uniform composition, represented by the analysis of Berzelius. The presence of animal substances in bones may be readily demonstrated by burning them in a vessel from which the air is excluded. * Treated in this manner, they turn black ; the car- bon of the animal substance remaining, while the hydrogen and oxygen are driven off. To the black residue obtained the name of animal or bone charcoal is given ; it is of great value in certain manufactures, owing to the property it possesses of bleaching various organic colors. It is extensively used in re- fining sugar; the crude dark brown sugar being dissolved in What are the proportions of animal and mineral substances in the bones of adults ? What are the proportions in children ? What is meant by rickets ? What is the composition of bone in old persons? What bone contains the greatest amount of mineral substance? What is animal charcoal ? How is it prepared ? What are its uses ? BONE tTNDEE THE MICEOSCOPE. 11 water to form a sirup, wWcli is passed through, a column of coarsely - powelered bone charcoal, twelve or fifteen feet in length, and escapes below as a colorless fluid, which is evapo- rated and crystallized in masses, and returned to the market in the form of crushed and white sugar. If the bones are burnt in a current of air, they finally be- come perfectly white; the mineral material, consisting chiefly of phosphate of lime, alone remaining. The bone-earth pro- duced in this manner is in the form of powder used to make cupels for refining gold and silver; it is also employed as a fertilizer. Avery pretty method: for separating the mineral from the animal materials is to place a bone in dilute hydrochloric acid, composed of one part of acid to ten or fifteen of water. In the course of a few days the acid dissolves all the 'hiineral sub- stance, leaving the animal material, which preserves the origin- al figure of the boiie, but is so flexible that it may be readily tied in a knot. The composi- tion and growth of bones may be satisfactorily studied by the examination of their sections un- der the microscope. With a suitable power the appearance in Fig. 8 is obtained. The large openings are called the haver- sian canals, through which the Fig. 8. Fig. 9. ^^"^"^^^fe" Section of Bone magnified 250 Diameters, showing LacuntB and Oanaliculi. Section of Bone magnified 50 Diameters, showing Haversian Canals. larger blood-vessels pass to nourish the bone. In Fig. 9 the fine lines are called canaliculi. They trav- erse the tissue in every direc- tion, and convey the fluid por- tions of the blood to the lacu-* nse or bone cells which are scat- tered throughout the fabric, and How is the refining of sugar conducted? Eor what purpose is bone-ash employed? Which ingredient of bone is soluble in acid? What is the appearance of bone under the microscope ? What are the havereian canals ? What are the lacunsa ? Cartilage oasifyiiig, magnified 10 Diameter. 12 CLASSIFICATION OF BOWES. Fig- If- are represented in Fig. 9 by the black masses. The development of bone first begins by the formation of a mass of cartilage which takes on the figure of the bone. In this a variable num- ber of spots of true bone grad- ually appear which are centres of ossification. Around these the mineral matter is deposited until it extends throughout the mass, and it becomes perfectly consolidated, and possesses the* rigidity necessary to, adapt it to the purpose for which it is intended. All bones are covered exteriorly by a membrane, in which the blood-vessels subdivide and form minute arteries, which en- ter the haversian canals to nourish the osseous tissue. To it the name of periosteum is given ; and so necessary is this mem- brane to the well-being of the osseous tissue, that any injury to it results sooner or later in the death of the bone. For convenience of description, bones are divided into three classes, long,:flat, and irregular. The first are found in the ex- tremities. They consist of a- shaft composed of hard, dense tis- sue, usually hollow, and filled with marrow or fat. The cavity is cylindrical in shape, and lined with a membrane similar to the periosteum. It is called the endosteum ; its duties are the same as those of the external membrane. The ends of the long bones are smooth, and enlarged to famish surfaces suitable for the formation of firm joints. The canal of the shaft does not extend to the ends of the bone, but disappears in a spe- cies of cellular structure, which is better adapted to the con- ditions which are to be fulfilled by the extremities. The flat and irregular bones usually inclose cavities, and are found in the skull, pelvis, and other regions. They are com- posed of two layers of hard, dense tissue, the interrnediate space being occupied by spongy tissue, thus combining strength with lightness, as is also the case with the ends of long bones. Bone, like the other tissues of the body, is subject to a num- ber of diseases, such as cancer and inflammation, but the spe- *cial trouble is the liability to fracture. When a bone is bro- ken, if the fractured extremities are kept properly injuxtaposi- How does the development of bone commence ? What is the periosteum ? What are the three classes of bones ? Describe a long bone. What is the endosteum ? How far does the canal of a long bone extend ? What is the difference in structure between the shaft and extremities of a long bone ? How are flat bones constructed? Kg. 11. / ^ rnonnL '^ THE SKELETON. 15 tion, tLey unite in a few days by the formation of cartilage, in which the mineral matter is gradually deposited, until, after the lapse of a few weeks, the juncture becomes more solid and dense than any other part. In the Hunterian Museum there are many singular examples of diseased skulls, sSme being, an inch thick, and others pos- sessing osseous growths from various parts. In one which be- longed to a prize-fighter, there are osseous projections from the rim of the orbits about three inches in length, which were pro- duced by injuries received in various encounters. LECTURE IV. BONES COMPOSING THE SKELETON. Numher of Bones in the Body. — Bones of the Trunk. — Pelvic Bones. The number of bones in the body varies at different ages, but in the adult there are 238. They may be conveniently studied under the following divisions : Skull- Trunk.. (Cranial 8 (Face 14 fNeck, thoraji', and abdomen 50 tPelvis 4 Upper extremities Aj^^t \ 64 Lower extremities 4 t§^ > 60 Internal ear 6 Teeth 32 238 The bones of the skull are divided into those of the cranium, which inclose the cavity in which the brain is placed, and those of the face. The latter are very irregular, while the former are true flat bones. The cranial bones are the frontal, occipital, sphenoid, ethmoid, two temporal, and two parietal. The frontal forms the forehead and the roof of the orbital^ cavities, in which the eyes are placed. ^ The occipital {Fig. 12) forms the back of the head and< part of the base of the skull. The large opening is the fora-^; men magnum, through which the spinal cord passes. The sphenoid {Fig. 13) bears some resemblance to a bat, be-' How is the fracture of bones repaired ? How m»ny bones are there in the body ? How many in each division ? Name the cranial bones. Describe the frontal, occipital, sphenoid, bones. 16 BONES OP THE ORANI0M. Fig. 12. Fig. 13. Sase of the SkuU, showing the Occipital Bone and Foramen Magnum. The Sphenoid. Fig.U ing very irregular in form. It articulates witli nearly all the bones of the skull, and forms the keystone to the arches of the cranium. The ethmoid {Fig. 14) lies between the cranium and the face. It is composed of a number of very thin plates of bone, rolled into a mass of scroll-work, and covered by mucous membrane, in which the filaments of the olfactory nerve terminate to form the organ of smeU. The Ethmoid Bone. Fig. 15. Fig. 16. Lateral view of Skull. Temporal Bone. The temporal hones aid in forming the base and sides of the skull. They are described as being composed of three parts: the mastoid, thick and cellular ; the squamous, very thin and brittle ; and the petrous, dense, hard, pyramidal in shape, and hollowed out in the interior into irregular cavities, which con- tain the small auditory bones. The sense of hearing is lodged in this part, the waves of sound reaching the interior cavities through an opening on the outside, called the meatus audito- Describe the ethmoid and temporal bones. BONES OF THE FACE. 11 Fig. IT. rw V r- rius extermis, while the auditory nerve gains access to the same cavities through an opening near the apex of the petrous part called the meatus interhus. The projecting arm of bone is called' the zygoma, and the smooth gle- noid cavity at its origin articulates with the lower jaw. The parietal bones are quadrilateral in shape, and form the sides and roof of the skull. The inner surface is grooved by arteries {.Mg. 17), the rupture of which is one of the serious consequences of fracture of the skull. • The bones of the face are three max- illary, two nasal, two palate, two malar, two lachrymal, two turbinated, and one vomer. iA Parietal Bone, inner Surface. Fig. 18. Pig. 19. Superior Maxillary, outer Surface. Superior Maxillary, inner Surface. Inferior Mazillaiy. There are two bones in the upper, and one in the lower jaw. The upper maxillaries form the floor of the orbital cavities, and present a number of projections, the most important of which are the alveolar process, in which the teeth are fixed ; the pal- atal, which forms part of the hard palate ;. and the nasal, which forms the side of the nasal cavity. The body of the superior maxillary presents a large cavity called the antrum or cave, the object of which is'to give resonance to the voice. The lower maxillary bone consists of a horizontal and ascending portion ; the ends are smooth, to ar- ticulate with the temporal bone, while the teeth are fixed into the alveolar process of the horizontal portion. The nasal iones form the upper hard part of the Fig. 20. , The NaaSl Bonea.. nose. What is the zygoma? What is the name of the articular cavity? . What are the three divisions of the temporal bone? What is the shape and position of the parietal bones? What are the bones of the face ? Describe the upper maxillary bones. What is the an- trum ? Describe the lovfer maxillary bone. Where are the nasal bones f B 18 DIVISIOlfS OF THE VEETEBRiE. The folate hones are shaped like the letter L, They assist in forming the hard palate. . The niala/rs form the outer part of the orbital cavities, and the npper hard part of the cheeks. The laeh/rymals are small and very thin. They form a por- tion of the inner side of the orbits, and are in contact with the nasal processes of the npper maxillary. The twrhinated hones are in the nasal cavity, and attached to the ethmoid, in order to increase the surface on which the oKac-^ tory nerve is spread. Fjg.21. Fig. 23. The Falate Bones. The Malar Bone. The Vomer. The vomer is shaped like a plow-share, and divides the na-< sal cavity into two equal lateral portions. ^ The bones of the trunk are the os hyoides, twenty-four verte- brae, twenty-four ribs, the sternum, two ossa innominata, the sa- crum, and the coccyx. The OS hyoides is situated in the throat, at the base of the tongue. ~' The vertehrcB are divided into three classes, seven cervical, twelve dorsal, and five lumbar. The cervical are the smallest, Fig. 24. Cervical Yertebra, Borsal Yertebra. Lumbar Vertebra. and are in the neck ; the lumbar are the largest, and form the Describe the palate bones. Where are the malar bones ? Describe the lachrymal bones ; the turbinated bones ; the vomer. Name the bones of the trunk. Where is the os hyoides ? What are the divisions of the vertebras, and how many in each ? In what part of the verte- bral column are the largest bones found ? THE VEETEBEAL COLTrMK. 19 Fig. 25. small of tlie back ; the dorsal aid in forming tlie back of the chest, and they all possess facets on the sides, by which they articulate with the ribs. Each vertebra consists of a body, and incloses an opening through which the spinal cord passes. The ring of bone of each vertebra that forms this opening terminates posteriorly in a sharp projection called the spi- nous process. The vertebrae are arranged one over another, and joined by ligaments and an in- tervening disc of elastic cartilage, so as to form a column, marked in the back by the row of rough projecting spinous processes. Between the verte- brae there are openings through which the spinal nerves pass. Considered as a unit, the vertebral column forms a series of curves : one in the neck, the convexity of which looks forward ; one in the chest, the convexity looking backward; one in the abdomen, with the convexity forward; and one in the pelvis, formed by the sacrum and coc- cyx, with the convexity backward. These curves, and numerous vertebrae with their connecting cartilages, give to the column great elasticity, which protects the brain from in- jury by the sudden jars it would otherwise be subjected to in jumping and such violent move- ments. The lower part of the column is support-, ed by the bones of the pelvis and legs, and in its turn gives support to the organs of the trunk, up- per extremities, and head. The ribs are about half an inch in wi4th, and curved upon themselves so as to form an arc of a circle. One of the extremities is round and smooth, to articulate with one or two vertebrae ; the other is rough, and gives attachment to a car- tilage, by means of which the ribs are connected to the sternum. The under edge of each rib is marked by a groove, in which the arteries of the chest lie, and are protected fi'om violence so per- fectly that they are not readily reached in any ordinary wound The Verteliral Column. Describe a vertebra. How are the vertebrse connected? Describe the curves of the vertebral column. How is the lower part of the vertebral column supported? Describe the ribs. How do their extremities differ ? How are the arteries of the chest protected ? 20 THE PELVIC BONES. Fig. 26. The Os Innominatum. by a knife. The seven upper ribs on eacli side are called true, and the five lower false ribs. The stermmi or breast-bone is flat, and connected with the ribs by costal cartilages; it articulates above with the clavi- cles. The ossa innommata,' so called from their want of resemblance to any other known natural object, are composed in infancy of three parts, which become consolidated into one bone in adults. They are called the^Hum, ischium, and pubes. The first is the flaring por- tion, which forms the hip bone ; the second is the lowest part, and terminates below in a rough mass called the tuberosity, which bears the weight of the body when in the sitting position ; the third is the anterior portion. The pubic bones unite in front to form an arch called the pubic arch, which is much more obtuse in the female than in the male. The three divisions of the innominatum meet in a smooth circular depression called the acetabulum, which accom- modates the head of the femur to form the hip joint. The sacrum is triangular in shape, and artic- ulates laterally with the ossa innominata — above with the last lumbar vertebra, and be- low with the coccyx. It forms the posterior' wall of the pelvic cavity, and is perforated on its anterior and posterior surfaces with a num- ber oi foramina or openings, through which the terminal divisions of the spinal cord pass. The Sacrum. rpg^ coccyx IS & Small triangular bone attach- ed to the tip of the sacrum ; it is the termination of the verte- bral column. ' The ossa innominata, sacrum, and coccyx form the pelvis, the 36 of which varies with the sex. In the male it is cuf)- shaped, while in the female the iliac bones flare out so as to give it more the form of a saucer, and the cavity is wider in all its dimensions, and not so deep as in the male. How many true and false ribs ? Describe the sternum. Describe the ossa innominata. What are the divisions of the os innominatum ? What is the tuberosity ? What is the acetabulum ? Describe the sacrum. Describe the coccyx. What is the pelvis ? Fig. 2T. BONES OF THE UPPER EXTEEMITY. 21 Fig. 28. The Clavicle. LECTUEE V. THE SKELETON — Gonimued. Bones of the Uppeir Metremity. — Bones of the Lower Extremity. ties ^Joints. — Ihsties which &iter0tio the Composition of Joints. — Joints and Bones form Levers. — Diseases and Wounds of Joints. The bones of tlie upper extremities are the scapula, clavicle, humerus, radius, ulna, eigM carpal, five metacarpal, and four- teen phalanges. The^ SGwputa, or shoulder-blade, is held in position by muscles which are attached to the vertebrae and ribs so that it is movable. ^' It is triangular in shape, the upper and outfer angle furnish- ing an articular surface called the ^*' ^''■ • glenoid cavity, which receives the head of the arm bone to form the shoulder-joint. , The clavicle is shaped like the letter /. It is commonly known as the collar bone : its duty is to keep the shoulder-joint out- ward and backward. It is the first bone in the body that is perfectly ossified. The humerus, or bone of the arm, is a long bone, as are all the rest of the bones of the upper ex- tremity except the carpal. The upper part is call- ed the head; it articulates with the glenoid cav- ity of the scapula. On the outer side of the head there is a rough mass called the tuberosity, to' which some of the muscles that move the arm are attached. The lower end of the bone is grooved, forming a hinge-like joint with the bones of the fore-arm. The radius and ulna are the bones of i\vi fore- arm. The ulna forms the elbow-joint, while the The Humerus. What are the bones of the upper extremity ? Describe the scapula ; the clavicle ; the humerus. With what cavity does the humerus articulate ? What are the bones of the fore- arm ? Which joint does the ulna chiefly form ? The Scapula. 22 BONES OF THE LOWER EXTEEMITT. radius forms the wrist. They are placed side by side, and ar- ranged so that the radius can move to a certain extent around the ulna, and give to the hand thie movement of rotation it possesses. {JEtg. 11.) The bones of the wrist, or carpal hones, are eight in ntmaber, and placed in two rows, the first containing the scaphoid, sem- ilunar, cuneiform, and pisiform ; the second the trapezium, tra- pezoides, magnum, and unciform. The metacarpallones are nve in number, one for each finger ; they articulate with the second row of carpal bones, and form the palm of the hand. There are iomteen phalanges, three for each finger and two for the thumb. The lower extremity is composed of the femur, patella, tibia, fibula, seven tarsal five metatarsal bones, and fourteen jfca- ' langes. They all belong to the order of long bones. Thefemui', or thigh bone, has the head set on the shaft by means of a neck, which forms an angle that varies with the age of the individual. In old age the angle is nearly ninety degrees, and consequently the neck of the femur supports the weight of the body in the most disadvantageous manner, and is very liable to undergo fracture. The upper part of the bone is furnished with a strong, rough tuberosity for the attachment of muscles. The lower end is expanded so as to form two condyles, separated by a deep groove ; it articulates with the tibia to form the knee-joint. The tibia and fihda form the leg. They are closely bound together, and are^not movable like the bones of the fore-arm. Which does the radius form? How many bones are there in the carpus? Name them. How many metacarpal bones are there ? How many phalanges are there ? Name the bones of the lower extremity. Describe the femur. How does the angle of the shaft and neck vary with age ? What are the bones of the leg? What are their relations to the knee and ankle joints ? The Femur. COMPOSITIOK OF JOINTS. 23 Fig. 32. They terminate below in processes called malleoli, whicli give great firmness to tlie ankle-joint. . The patella lies in front of and protects the knee-joint. It is inclosed in the tendon of tke muscles of the thigh, and ena- bles tkem to act to greater advantage. _ The tarsal hones are arranged in two rows. The first con- sists of the astragalus, which ar- ticulates with the bones of the leg to form the ankle, and the os calcis, which forms the heel. The second row is composed of the cuboid, scaphoid, and three cunei- form bones. The metatarsus consists of five bones, one for each toe. They form the sole of the foot. There are fourteen phdkmges, three for each toe, except the large toe, which has two. The bones of the internal ear will be described in connection with the sense of hearing. The teeth belong properly to the function of digestion, and will be studied in connection with it. The Foot THE JOINTS. Bones are united together so as to form either immovable or movable joints. The best example of the first class is furnish- ed by the skull. In it the various bones are dovetailed into each other along their edges, to form perfectly unyielding joints called suiim-es, which may be broken, and the bones obtained separately, by filling the cranial cavity with well-dried peas, and adding water, when the peas swell and force the bones apart. The joints of the second class vary greatly in the de- free of mobility they possess, from the slidmg motion of the ones of the carpus on each other, to the hinge-like motion of the knee or elbow, or the almost universal mobility of the ball and socket joints of the hip and shoulder. The tissues which enter into the formation of a movable joint are, 1st. The smooth articular ends of the bones ; 2d. A Describe the patella. Name the tai-sal bones. How many metatarsal bones and pha- langes are there ? Describe the two varieties of joints, and give examples of each. What are sutures ? What tissues enter into the formation of a joint ? 24 CLASSIFICATION OF JOINTS. Fig. 33. covering of very dense polisted cartilage, wMch gives a sligM degree of elasticity, and aids in reducing the friction ; 3d. Liga- ments, wMch bind tlie bones togetlier ; 4th. The synovial mem- brane or sac, which contains the fluid, and lies between the cartilages of the joint, its object being to reduce the friction ; 5th. Muscles, which mbve the bones ; and, 6th. Nerves,' which govern and regulate the actions of the muscles. The osseous tissue has already been described. Cartilage consists of cells and fibrous tissue. Liga- ment is .composed of white fibrous tissue, in wMch the cells have be- come elongated into mere lines ; it is admirably adapted to the pur- pose for which it is employed. The synovial sac is also composed of fibrous tissue, and lined witM se- rous membrane. These are the es- sential tissues of the joint; the muscles and nerves are auxiliary. We may therefore pass at once to the study of the joints, and then take up the examination of the muscular and nervous tissues. All the long bones, and some of the bones of the other class- es, are used in the construction of movable joints, serving either as levers to move the body, or to carry on some process neces- sary to the well-being of the system, as, for example, mastica- tion. There are three classes of levers, all of which are repre- White Fibrous Tissue, magnified 300 Diameters. Fig. 84 Fig. 35. Fig. 36. Lever of 1st Glass. Lever of 2d Glass. Lever of 3d Glass. sented in the body. In the first class, the falcrum is between the power and the resistance ; in the second, the resistance is What is cartilage ? Describe cartilage and ligament. Describe the synovial sac and fluid. What are the varieties of levers f COMPOSITION OF MUSCLE. 25 ia the centre; and in the third the power is in the middle. In the systems of levers in the body, the fulcrum is the joint and the power the muscle. In throwiag the head backward we have an example of a lever of the first class ; in raising the body on tip-toe we have an example of the second; and in flexing the fore-arm on the arm we hdve an example of the third. Joints, like the other parts of the body, are liable to inflam mation. When the ligaments are involved, it is called rheuma- tism ; this sometimes passes into a chronic state, and is exceed- ingly painful. When the sjmovial membrane and cartilages are involved, it is called white swelling, which is very apt to terminate in a union of the bones, and entire loss of the use of the joint. Sometimes small hard cartilages are formed in the knee-joint, which slip between the ends of the bones in walk- ing, and produce the most excruciating pain. Wounds of the ' large joints, though they may appear to be insignificant, are very dangerous, and often cause death if the joint is opened to the aecess of air. LECTUEE VI. THE MUSCULAR SYSTEM. The 'Muscular Tissue. — Microscopic Characters of voluntary and involun- tary Muscle Cells. — Tendons and their Position. — Divisions of Muscles. — Muscles of the Head and Neck. — Of the Upper Matremities. — Of the Trunk. — Of the Lower Extremities. The muscular tissue forms the bulk of the body ; it is very freely supplied with blood-vessels, and is of a deep red color in the majority of animals, forming the lean meat or flesh — an ex- cellent example being the beef prepared for sale in the mar- . kets. There are, however, exceptions to the general law, as in the breasts of fowls, where it is white; this is supposed to be in part due to the fact that the pectoral muscles in such crea- tures are not used to any great extent, and they therefore un- dergo a fatty degeneration, and lose Iheir color. The chemical elements entering into the composition of this tissue' are car- bon, hydrogen, oxygen, nitrogen, and sulphur; it is consequently a nitrogenized body; it also possesses the power of contractility, which IS in part due to the manner in which it is constructed. What diseases affect joints ? Wliat are false cartilages ? What wounds of joints are most dangerous ? What is the color of muscle ? Why are the pectoral muscles of fowls white ? What chemical elements enter into the formation of muscle ? 26 VOLrNTAEY AND INVOLUNTAET MUSCLE CELLS. Kg- 37. Fig. 38. rig. 39. Blood-vessels of Muscular Tissue. Rectangular Cells of Voluntary Musde. Striped Muscular Fibre. Muscles may be classified under two heads : tlie voluntary, controlled by the will, as "the muscles of the extremities ; and the involuntary, which act independently of the will, and even without its knowledge, as the muscular coat of the stomach and intestines. The microscopic characters of the two -varie- ties are very different, voluntary muscle fibre being composed of rectangular-shaped cells, placed end to end like the cells of conferva, and having a rectangular nucleus. The fibres are Fig. 40. Involuntary Muscle Cells. Fig. 41. Unstriped Muscle. fornied into bundles, the arrange- ment of the cells being such that the nuclei are side hj side, and form lines. Owing to this pe- culiarity, it is often called striped muscle. Involuntary fibre, on the con- trary, is composed of »elongated cells, and there is no specif sys- tem in their arrangement ; conse- quently, the nuclei do not form lines, and it passes under the designation of unstriped muscle. The force generated by the What is the difference between voluntary and involuntary muscles, and the cells compos- ing them ? MTTSCLES OF HEAD AND NECK. 29 contraction, of muscular fibre is applied to the bones tlirougli the intervention of an inelastic band of white fibrous tissue called tendon. One extremity of each fibre of a muscle usual- ly arises directly from a bone, and the other terminates in the tendon, which passes over one or more joints, and is attached to another bone. The tendon is sometimes on the side of the miscle, giving an appearance similar to that afforded by an or- dinary quill pen. These are called penniform. Sometimes fibres branch off from both sides of the tendon ; such are Jripeii- niform. In some muscles the fibres radiate from a central point, as in the iris of the eye ; these are called radiate. It is impossible, within the circumscribed limits of a text- book, to describe all the muscles of the body ; but it is desira- ble that every educated person should know something regard- ing the names, position, and shape of the external muscles, which are situated immediately under the skin, and give to the body its beautiful contour and gracefully curved outline. Pa,inters and sculptors endeavor to represent them in various works of art, and every one takes an honest pride in develop- ing and exhibiting a graceful muscular limb. The voluntary muscles may be described under six divisions, ' those of the head and neck, of the trunk, and the four extrem ities. The ends of the muscles are spoken of as the origin and insertion ; the first is the portion in which the muscular fibres are attached directly to the bone ; the insertion is the tendin- ous end ; it is usually attached to the most movable bone. The muscles of the head and neck are the occipito-frontalis, which lies immediately under the hairy scalp, extending from the eyebrows to the back of the head. Some persons possess the power pf moving this muscle to a very considerable degree. Two muscles, the temporal and masseter, arise from the tem- poral fossa on the side of the skuU, %iid are inserted into the ascending portion of the lower jaw; they give motion to the jaw, and a,re employed in the act of mastication. The cheeks are formed of a muscle called the buccinator. The muscle that forms the lips is the orbicularis oris ; it is employed in the act of kissing, and consists of a number of circuit bands that pass around the mouth. A similar circular muscle surrounds each of the eyes ; it is called the orbicularis palpebrarum. The great muscle that forms the nape of the neck is the trapezius ; How is the force generated by muscles applied? What is a penniform muscle — bipenni- form — radiate? Where;,are the largest muscles found? What are the divisions of mus- cles ? What is the origin of a muscle ? What is its insertion ? What are the muscles of the head and neck ? Describe their actions. 30 MUSCLES OF EXTEEMITIES AND TRUNK. it throws the head back ; it is opposed by the sterno-cleido- mastoid muscle, which bends the head forward on the chest. When both sets of muscles act together, the head is kept firm- ly fixed, as in carrying burdens. There are many other mus- cles in the head and neck,' but' these are the most prominent, and can be traced in the majority of paintings or pieces of sculpture. ^ m The muscles of the upper extremities are the deltoid, tri- angular shaped, and covering the shoulder ; it raises the arm from the side of the body to a horizontal position. The trape- zius aids in carrying it up to the vertical line. The biceps, or large muscle on the front of the arm, flexes the fore-arm on the arm, and makes the preparation for striking a blow. The tri- ceps extends the fore-arm on the arm ; it is on the back of the humerus, and is used in delivering a blow. The muscles of the fore-arm are all small, and do not give any special marks or contours, except in persons in whom the muscular system is exceedingly well developed ; we must therefore leave the de- scription of them to more extended works on anatomy. — The muscles of the trunk are the pectoralis major and mi- nor. They form the breasts, and, taking their origin from the sternum and inner edges of the upper ribs, are inserted into the humerus; they are employed in folding the arms across the chest. Opposed in action to the^pectorals is the latissimus dorsi,' which, arising from the lower two thirds of the vertebral column, is inserted into the himienis, and throws the arms backward ; they are greatly developed by the exercise of row- ing. The muscle which extends from the lower part of the sternum to the pelvis is called the rectus abdominalis. As is the case with nearly all the muscles of which we have treated^ it is one of a pair ; with its fellow it forms the anterior waU of the abdomen ; it is divjded transversely into three portions, the divisions being well marked only in very muscular indi- viduals. The muscles which complete the walls of the abdom- inal cavity are the obliquus externus, obliquus intemus, and transversalis. The fibres of these muscles are arranged, as their names indicate, s^ as to cross each other, and produce in their action an equable pressure on the organs contained in the ab- dominal cavity. In addition to these, there are a great num- ber of small muscles in the back and between the ribs ; the lat- ter are called intercostals ; they aid in carrying on respiration. What are the muscles of the upper extremity f Describe their actions. Kame the mus- cles of the trunk. Describe their actions.- Fig. 43. MUSCLES OF THE LOWER EXTEEMITT. 33 The muscles of the lower extremities are, 1st. Those which form the Isuttocks ; they are called the glutei muscles. They are arranged in three layers, viz., external, middle, and internal. Though these muscles exist in the lower animals, they are de- veloped to a far greater extent in man, giving to him the pow- er of retaining the erect position. Opposed to the glutei are the iliac and psoas muscles, which arise from the abdominal surface of the vertebral column, and, passing over the pubic bone, are inserted into the femur. The great muscles of the thigh are the rectus femoris, which passes from the iliac bone to the patella; the vastus externus and vastus internus, which take their origin from the outer and inner surfaces of the fe- mur, and are inserted into the patella ; they extend the leg on the thigh. ^The muscle which runs obliquely across the thigh, from the iliac bone to the inner edgfe of the tibia, is call- ed the sartorius, or tailors' muscle, since it is employed in bend- ing the lower extremities into the position asstmied by persons of that ift-ade while at their work. The muscles that are in- serted into the patella are in reality attached to the tibia, for a strong ligament, about two inches in length, passes from the lower edge of the patella, and is attached to a rough surface on the anterior edge of the tibia. The largest muscle on the back of the thigh is the biceps ; it flexes the leg on the thigh, and, since it takes its origin in part from the ischium, also aids in extending the tMgh/)n the trunk. The muscles of the leg are the gastrocnemiusfoii the back of the leg, giving it its full- ness ; it extends the foot on thefleg, and raises the body in walking. The tibialis anticus, iand other smaller muscles on the front of the leg, flex the foot on the leg, and oppose the gastrocnemius. The involuntary muscles will be described together with the organs and functions with which they are connected. What are the muscles of the lower extremity ? Describe their actions. c 34 THE. DIGESTIVE TKAOT. LECTURE VII. OEGAHS OE NUTRITION. Fig. 44. The DigeBtive Tract. Divisions of the Nutritive Process.-^ * Divisions of the Digestive Ajpparor tus. — Distinctive Characters of Mu- cous and Serous Membranes. — TTie Composition and Classification of the Teeth.-;-Descriptio9i of the Duc- cal Cavity. — The Pharynx. — The (Esophagus. — The Stomach. — The four Serous MemJbranes. — The Mu- cous Coat of the Stomach. — The Fol- licles of the Stomach. — The Phds of the Stomach. NuTEiTioN is divided into three distinct processes, viz., digestion, alDsorption, and circulation. We shall commence w^ith the study of digestion, and the description of the anatomy of the apparatus by which it is accomplished. 1, the tongue ; 2, pharynx ; 3, oesophagus ; 4, soft palate ; 5, sec- # tion of laiynx ; 6, hard palate ; 7, epiglottis ; 8, thyroid cartilage ; 9, spinal cord ; 10, bodies of ver- tebrae ; 11,12, spinous processes ; 13, cardiac end of the stomach; 14, splenic extremity ; 15, pyloric end; 16, greater curvature; 17, lesser curvature ; 18, the pyloric valve ; 19, first portion of duode- nmn; 20, second portion; 21, third portion ; 22, gall bladder ; 23, cystic duct ; 24, hepatic duct ; 25, ductus communis choledo- chus; 26, its entrance into duo- denum ; 27, pancreatic duct ; 28, 29,jejunum; 30, ileum; 31, open- What are the divisions of the nutritive procees ? MUCOUS AND SEEOtrs MEMBKANB8. 35 Fig, 45. ing of ileum into large intestine;. 32, ileo-colic valve; 33, ileo- csecal valve ; 34, caecum ; 35, appendix vermiformis ; 36, as- cending colon ; 37,'transverse colon ; 38, descending colon ; 39, sigmoid flexure ; 40, rectum ; . 41, anus. For. convenience of description, the digestive apparatus may- be considered under six divisions : 1st. The mouth or buccal cavity ; 2d. Pharynx ; 3d. CEsophagus or gullet ; 4th. Stomach ; 5th. Intestines ; 6th, Glands. The buccal cavity is closed in front by the lips, which are composed of muscle (orbicularis oris), and cover- ed by mucous membrane. This mem- brane has a composition similar to that of the skin ; it secretes a glairy fluid called mucus, and lines the di- gestive apparatus throughout its whole length, and may be described as being continuous with the skin. In some of the lower orders, as the polypes and hydra, it is not only continuous with the skin, but it also can at any time, by merely inverting the creature, be made to take on the action of the skin, while the skin be- comes at the same time the digestive surface. Mucous membrane is generally in the form of a tube, and communicates freely with the external air. When it is inflamed, the diseased condition terminates in the production of pus or matter. Serous membrane, on the contrary, is always in the form of a closed sac, and does not communicate with the external air. When inflamed, the dis- ease usually results in the formation of adhesions which .unite the surfaces of the sac together. Pus is very rarely formed, and when it is, it is a very unfavorable symptom, usually re- sulting in the death of the patient. Immediately' within the lips are the gums, composed of the alveolar processes of the maxillary bones, covered by thick mu- What are the divisions of the digestive apparatus ? Describe the buccal cavity. What are the properties of mucous membrane ? What is the difference in form between mucous and serous membranes? What are the results of inflammation in both membranes? De- scribe the gums. The Hydra. 36 ANATOMY OP A TOOTH. Fig. 46. cous membrane. In the gums the teeth are iittedj their func- tion Tbeing to masticate the food. The parts composing a tooth are the crown, a, which projects above the gtuns, c; the roots or fangs, b^ which are fitted in the maxillary bones. ■ The crown is covered by a dense, hard material, called enamelye/ while the bnlk of the tooth consists of substantia ftstoidea, or bone ivoryj^^. The cavity in the interior of the tooth is represented at