A new manual of electro-therapeutics, and a brief treatise on anatomy and physiology

Preface

In consideration of the fact, accepted by liberal and progressive practitioners, that “ all medical systems ” and “ curative agents ” belong to the true physician, irrespective of “ pathy,” should be combined without violation of any true “ code of medical ethics ,” as a grand polytherapeutic, the author is induced to offer the present volume on Electro-Therapeutics, not antagonistic to, but as a correlation of the other systems of Therapeutics.

The many innovations upon the pedantry of certain factions, during the past ten years, rendering theories once scouted at and denounced with caustic opprobrium and prejudice, as unsound , the present accepted practice of best authorized medical regents, with undoubted attributes of sound scientific acumen, is a second plea for this exhaustive hand-book upon the principles and practice of Eleetro-Therapeutics.

Morover, the growing necessity and constant demand for a rationale of Electrical cure, safe and sure, beyond the hap-hazard of unscientific and unphysiological experiments for a system based upon wellproven methods, available alike for private and general practice, has urged the author to tabulate in simple terms, and adapted to simple apparatuses, the following principles for such practice. The author does not deny the efficacy nor the skillful workmanship van

PREFACE.

of various batteries, but has sought to offer a concise and complete system as adapted to one electrical machine and methodical applications, which will be effectual when administered intelligently and in close adherence to certain given principles, operating in harmony with physiological laws.

Where, as the author has, unlimited confidence in the efficacy resulting from scientific application of electricity, a confidence educed from personal experience and date gleaned from daily use of this subtle element; she does not hesitate to denounce most emphatically its exercise by unscientific hands, as an agent capable of originating great mischief, and distressing physical derangements.

A careful and thorough diagnosis is requisite to facilitate successful results. The author only vouches for applications resulting “thus and so,” when all the conditions are observed, and the proper disease is addressed by the operator, and the proper discrimination of what kind of electricity should be used to affect various tissues, organs, nerves, ligaments, blood, etc., for such differences do exist, and are herein maintained upon a firm basis of experience and well attested facts.

The. author only hopes that this grand science of sciences will henceforth arouse new interests, and medical colleges will give the subject proper consideration hereafter, so that the student shall be conversant with the subtle uses, and avoid the unscientific abuse, of Electro-Therapeutics.

Philadelphia, Pa., March, 1875.

Preface

7-8

Chapter I

Human Anatomy and Physiology, 18 ; Elements of Human Organism, 19 ; Respiratory Apparatus, 21 ; Circulation of the Blood, 23 ; Valves of Pleart, 25 ; Systematic Circulation, 27 ; Salivary Glands, 29 ; Alimentary Canal, 31 ; Lacteal and Thoracic Ducts, 32.

Chapter II

The Brain and Nervous System, 34 ; Life Principle, 35 ; Grey’s Nerve Force, 36, 37, 38 ; Human Battery, 39 ; Brain Matter, 40 ; Medulla oblongata, 43 ; Cranial Nerves, 45 ; Spinal Nerves, 47 ; the Sympathetic System, 49 ; Review, 51.

Chapter III

Organs of Generation, 53; the Ovaries, 55; the Genito-Urinary Organs, 57.

Chapter IV

Anatomical and Pysiological Illustrations, 58 ; Cerebrum, 59 ; Pneumo-gastric Nerve, 60 ; Spinal Cord, 61 ; Sympathetic Nerve, 63 ; Sympathetic Nerves, 65 ; Lung and Heart, 66 ; Distribution of the Nerves, 67; Front View of Thorax, 68 ; Reflections of the Peritoneum, 70 ; Sectional View of Nose, 71 ; Alimentary Canal, 72 ; Anterior View of Uterus, 73 ; Section of Female Pelvis, 74; Pelvic Viscera of Male, 75 ; Articulation of Pelvis, 76 ; Lymphatics and Lacteals, 78.

X

Chapter V

General Review, 78; Table of Bones, 79; Table of Veins, 80; Veins which form Inferior Vena Cava, 81 ; Table of Principal Arteries of the Body, 82 ; Arteries Temporal and Maxillary, 83 ; Arteries of Thorax, 85 ; Arteries, 86 ; Crural Artery, 87 ; Table of Cranial Nerves, 88 ; Sixth, Seventh and Eighth Nerves, 89 ; Table of Spinal and Sympathetic Nerves of Face and Neck, 90 ; Table of Spinal Nerves of Upper Limb, 91 ; Table of Spinal Nerves in the Abdomen, 92 ; Table of Sympathetic Nerves of the Abdomen, 93 ; Pneumo-gastric Nerve in Abdomen, 94 ; Table of Muscles — the Head is moved, 94 ; the Neck is moved, 95 ; the Trunk is moved, 95 ; the Scapula is moved, 95 ; the Humerus is moved, 96 ; the Forearm is moved, 96 ; the Corpus is moved, 96 ; the Thumb is moved, 97 ; the Fingers are moved, 97 ; the Thigh is moved, 97 ; the Thigh is rotated, 97 ; the Leg is moved, 98 ; Average Weight of each Organ, 98 ; Size of Organs, 99 ; Exudation and Absorption of the Lymphatics, 99, 100, 101.

Chapter VI

Medical Electricity, 103 ; Primary and Secondary, 104 ; Currents, 106 ; Selection of Currents, 107 ; Administration by Plates, 109; Modes of Addressing Treatment, ill ; Vapor Bath, 113 ; Author’s Appliances, 115 ; Brass Plates Brasier, 116 ; for Chemical Fumigations, 117; Portable Vapor Bath and Boiler, 118. Illustrations : Case of Battery, Electrical Appliances, Dr. Kidder’s Batteries, Improved Cell Battery, Equal Alternating Current Apparatus, Primary Cell Battery, Galvano- Caustic Battery.

CONTENTS.

XI

Part II. The Rationale Of Cure

Electrical Diagnosis 134

Paralysis from Centric Lesion, etc. 135

Local Organic Diagnosis 136

Spinal Diagnosis... 136

Cranial Diagnosis, Difference in Electrical Currents 137

Different Currents, A B, BD 138

B E, C D, C E, D E 139

Direction and Choice of Current 140

Basis for Treatments 141

Particular Maladies — Manipulations 142

General Debility — Depletion of Nerve Power — Lassitude .. 142

Scrofulosi.s — Suspended Animation 143

Shock — Collapse 144

Chills of all kinds 145

Congestive Chills 145

Fever 146

Fever, continued 147

Severe Inflammation in General 148

Sleeplessness 148

Nervousness 149

Intermittent Fever 149

Remittent Fever 150

Continued Fevers — Typhoid 150

Ulceration — Stupor — Haemorrhage — Diarrhoea 15 1

Yellow Fever — Eruptive Fevers — Measles 152

Scarlet Fever. 153

Catarrhal Fevers — Influenza — Common Cold 154

Rheumatic Fever — Acute Rheumatism 155

Affections of the Heart, Liver and Stomach 156

Chronic Rheumatism 156

Lumbago — Myalgia — Muscular Rheumatism — Sciatica —

Cerebro-spinal Meningitis — Spotted Fever. 156

CONTENTS.

xii

Vertigo.. 1 57

Headache, nervous, gastric, etc 158

Sick-headache 159

Insanity — Imbecility — Melancholy 160

Malposition of Organs 161

Mania 162

Intemperance 162

Narcotic Poisoning 163

Chronic Narcotism 164

Poisoned Wounds. .. 164

Bites of Rabid Animals 165

Chronic Symptoms Neuralgia and Toothache 166

Hysteria 167

Chorea 168

Convulsions, epileptic, infantile, puerperal, hydrophobic, tetanic 169

Epilepsy 170

Infantile Eclampsia 171

Puerperal Eclampsia : 171

Tetanus 172

Prevention of Miscarriage 172

Pregnant Vomiting — Labor Pains assisted 173

Apoplexy 174

Paralysis 174 — 176

Paralysis of Lower Extremities 177

Local Congestions, Inflammations and allied Diseases.

Inflammation of the Brain 179

Affections of the Eyes :

Disordered Vision. 179

Conjunctivitis — Ophthalmia 180

Lachrymal Obstruction 181

Otitis — Earache — Deafness 182

Nasal Catarrh, acute, chronic 182

CONTENTS. XU1

Nasal Polypus - 183

Stomatitis 183

Tonsilitis — Pharyngitis — Diphtheria 184

Enlarged Tonsils 184

Chronic Enlargement of Tonsils 185

Parotitis — Mumps 185

Tracheitis — Bronchitis — Asthma 187

Phthisis — Pneumonia 188

Pleurisy 189

Carditis — Cardiac Paroxysms — Chronic Heart Diseases 190

Dyspepsia 191

Paretic Diaphragm 192

Inflammation of Abdominal Organs :

Peritonitis, etc. 192

Constipation — Colic — Tenesmus — Cramps — Painter’s Colic,

etc 193

Diarrhoea — Dysentery, Colitis, Enteritis, Peritonitis 194

Cholera and Cholera Morbus 195

Albuminuria — Diabetes 196

Incontinence of Urine 200 — 201

Cystitis — Metritis — Ovartitis 202

Ulceration of the Genito-Urinary Passages __ 203

Uterine Displacements 204 — 206

Uterine and Vesical Prolapsus 206

Uterine Displacements 207

Ovarian Treatments 208

Dysmenorrhoea, or Painful Menstruation 209

Metrorrhagia, or Uterine Haemorrhage 209

Uterine Inertia in Labor 210

Impotence 210

Gonorrhoea 211

Syphilis — Primary Ulcers — Bubo _ 211

Constitutional Syphilis — Hydrocele — Varicocele 212

XIV

CONTENTS.

Varix of the Legs — Varicose Veins — 213

Aneurism .. - 2x3

Various Aneurisms, Indurations, Tumors (Benign and Malignant 214

M ammary T umors — Cancers 215

Uterine Tumors — Cauliflower-Growths-— Polypi. 216

Ovarian Tumors, cystic, fibrous.- 216

Tumors on the Extremities — Encephaloid Cancers 217

Haemorrhages 218

Syphilitic Taint — Open Cancer — Colloid Cancer 2ig

Erysipelas 220

Furunculus — Boil.. 22 r

Panaritium, or Run-a-round — Ingrowing Nails — Burns —

Frost-bite — Abscesses — Sprains 222

Anthrax — Carbuncle — Felon — Whitlow 223

Pustula Maligna 224

Ulcers — Fistula 225

Cutaneous Diseases 226

Fumigations for Vapor Baths 227

Leprosy — Psoriasis (Itch) 228

Small-pox, or Varioloid Diseases of Joints 229

Synovitis Suppuration 230

Infiltration of Pus — Morbus Coxariaus 231

Hip-joint Disease — White Swelling 231

Stiff Joints — Deformed, Contracted Dry Joints — Weak Joints 233 Curvature of Spine 234

NOTICE.

This work may be ordered from the Author, the Editor, W. B. Keen, Cooke & Co., Chicago, and J. B. Lippincott & Co., Philadelphia.

Price $10. Free on receipt of price.

PART I.

Chapter I. Human Anatomy And Physiology

The author feels it necessary, before proceeding to a consideration of Electro - Therapeutics, to give in as comprehensive language as possible the anatomical structure and physiological organism which constitutes life and health, or disease, in the human form, herein subsequently to be acted upon.

Assuming that the readers stand in the light of uninformed pupils, the effort on the part of the author will be directed to render as lucid and give as wide a range of ideas upon these subjects as possible, without the perplexity of wading through technical nomenclature.

An organism is a body composed of separate parts called organs. It is definite in form and function, and each part or organ is necessary to the full perfection of the whole structure. Unorganized matter, or the contrary, is not necessarily made up of separate parts ; it does not consist of organs, nor are the sizes and i8 forms of inorganic masses limited or definite, except in respect to crystalline formations, which are always definite. Inorganic substances, such as minerals, earths, fluids, gases, etc., may be unlimited in size, and heterogeneous in the shape of their several masses ; but plants and animals always assume certain definite shapes and sizes, ranging within certain normal limits. You may break up and divide inorganic bodies into any number of subdivisions, and each part shall retain its identity, and be still the same substance; but you can not take from an organized body any portion, however minute, without damaging its integrity, and depriving it of an essential part of its structure.

The study of anatomy deals with and describes dead matter. Physiology treats of the powers, motions, and functions of living bodies. Physiology also includes a survey of all animated structures, from the simplest forms of the vegetable to the highest conditions of animal existence; but as the human structure may be regarded as a microcosm, including every form of life below itself, so the study of man is the most instructive and comprehensive of all other branches.

The human organism is made up of matter and force, — matter, in its three states of solid, fluid and gaseous; and force, including all the various forms of motion, the sum of which we call life.

The fluids in animal bodies exist chiefly in the form of chyme, chyle, lymph, blood, the different juices secreted by special glands, and water.

The solid portions are called tissues, and consist of bone, muscle, cartilage, membrane, adipose, cellular

ELEMENTS OF HUMAN ORGANISM.

and areolar tissues, nervous matter, hair, teeth, and nails.

The fluids contain in solution all the materials for the formation of solids, and as the fluids and solids are mutually convertible, and constantly interchanging states, their constituent elements do not differ materially from each other.

The following elements are found in more or less variable proportions in the human system : oxygen, hydrogen, nitrogen, carbon, sulphur, phosphorus, silicon, chlorine, fluorine, and iron. There are other elements occasionally found in the body, such as manganesium, aluminum, and copper, but these are rather incidental than constant in their presence.

There are, without reckoning the teeth, about two hundred and eight pieces of bone, arranged for the most part in pairs, and grouped symmetrically on either side of the body. The bony structure may be divided into the cranium inclosing the brain, the bones of the face, the trunk, including the sternum, vertebrae, twelve pairs of ribs, the collar-bones and shoulder-blades, and the pelvis, which supports the abdominal regions. The lower extremities consist of the thigh and knee-bones, the legs, feet and toes. The upper extremities include "the arms, hands and fingers.

The cranium incloses the brain and its appropriate system of blood-vessels, and also bounds the face, organs of special sense, and cranial nerves. The thorax and vertebrae inclose the heart, lungs, blood-vessels, and spinal cord. The pelvic basin supports the stomach, liver, pancreas, spleen, bladder, intestines,

ELECTRO- THERA PEUTICS.

and organs of generation. Thus the bony structure performs the important office of protecting, as in an inclosed lattice-work, the vital organs. There are certain pieces of bone in the pelvis, face, head, and spine which are single and uniform ; all the rest are arranged, like the extremities, in pairs, on either side of the body. Each pair of bones differs in some respects from every other pair, and all are fastened together by joints called articulations. The cranium is not formed of one compact mass, but consists of several pieces, firmly united by the interlocking of notched edges, called sutures. The long bones of the extremities are hard, hollow cylinders, lined with membrane, on which blood-vessels are distributed for the nutriment of their substance. The long bones are expanded at the extremities, so as to present surfaces for articulation with other bones. Some of these bones are united by a ball and socket, others by flat surfaces, but all are firmly bound together by muscles and ligaments, and the end of each bone is covered with a layer of cartilage, lubricated by means of a sac of serous membrane, which effuses a peculiar fluid, called synovia, the use of which is to keep the joints moist and supple.

The bones are composed, in the first place, of cartilage, which is converted into osseous tissue by the deposition of phosphate and carbonate of lime. In infancy, cartilaginous or animal matter constitutes the chief portion of the skeleton ; in adults, the lime increases, hardening the bones, and communicating strength to the frame ; in old age, however, the animal matter dissipates so rapidly that the bones become ex-

RE SPIN A TOR Y APPARA PUS.

2 i

ceedingly brittle, — hence it is that fractures to persons in advanced life are so dangerous and difficult to repair.

Without entering into the minutiae of detail which belongs to the anatomy of the bones, it is enough to call attention to the beautiful mechanism of which the frame-work is composed, the position it occupies in the human economy, and to note how admirably the finest principles of mechanics are carried out in tne articulation of the several joints, and the freedom with which every part of the structure moves.

The respiratory apparatus commences with the mouth, which conducts the inhaled air through the trachea (windpipe) into the lungs. The trachea is a strong, highly elastic tube, composed of muscular, fibrous, and mucous membrane, all of which line and connect about eighteen cartilaginous rings, the contractile action of which is admirably adapted to produce the various inflexions of the voice essential in speaking or singing.

We may here pause to remark that all portions of the viscera or internal organs that are exposed to the air are lined with mucous membrane, and all the internal organs themselves are inclosed in sacs of serous membrane, the office of which is to secrete a watery fluid, called serum. It is by the effusion of serum that the various organs are lubricated, and any undue irritation, from their friction one upon the other, is avoided.

The trachea terminates, as it enters the thorax, in two arches, called bronchi, and these, dividing off into the right and the left lung, subdivide and ramify into

ELECTRO - TIIERA PE U TICS.

an immense system of tubing, every fiber of which ends in a minute air-cell. The tissue of the lungs is composed of fine areolar membrane, air-cells, bronchial tubing, arteries, veins, and capillaries. The air-cells are composed of microscopic sacs of membrane. The bronchial tubes, veins, arteries, and capillaries of the lungs are all attenuated to the utmost degree of fineness, and so profusely distributed that the entire mass of the lungs may be said to consist of an immense surface of membrane, with blood-vessels on one side and air-cells on the other. The blood and air do not come into contact, although the fine and permeable character of the membrane permits the nutritive quality of the blood to pass into and nourish the air-cells, and the vitalizing properties of the inhaled air to act upon and change materially the character of the blood. It has been estimated that there are at least six hundred millions of air-cells in the lungs, each one of which is supplied by an artery communicating with a vein, and inflated by the air inhaled in the act of inspiration. The surface presented by the membrane of the lungs would, it is supposed, cover more than thirty times that of the whole body, and the capacity for inflating this light, spongy tissue is provided for, first, by the elastic intercostal muscles which connect the ribs together and expand with every respiration, and next by the action of the large muscular membrane called the diaphragm, which separates the thorax from the abdomen, and alternately curves upwards and downwards with the actions of inspiration and exhalation performed by the lungs. The chief function of the respiratory organs

CIRCULATION OF BLOOD.

2 3 is that of aerating the blood, which is carried into the lung-tissues by the pulmonary artery from the right ventricle of the heart. At this point the blood is finally collected by the veins from all portions of the system, and, being charged with the impurities and effete matters, gathered up in traversing the body, presents the appearance of a dark purple, almost black, fluid, when poured through the right vena cava or large vein into the heart.

By the exposure of the venous blood to the oxygen of the atmosphere inhaled through the lungs, its impurities are in part disengaged and given off in the form of carbonic acid gas; the whole mass of blood, or nearly the whole, becomes changed in tone and color; the dark purple hue is converted into a bright scarlet, and by the time the pulmonary circulation is completed, the blood is arterialized and poured back into the heart through the left auricle, in a condition sufficiently renovated to form pabulum, for the support and nourishment of the entire system.

We must now trace in more detail the circulatory process, and note the intimate connection and interdependence which it maintains with the respiratory system. The heart is the center of the circulatory apparatus, and it is situated in the thorax, between the right and left lungs. The point or apex slants forwards towards the left lung, on which it slightly impinges, the base or broad part inclining backwards and upwards towards the right shoulder. Although the formation of muscular fiber is uniform in all parts of the system, the closely-knit and strongly-packed fibers of the heart

ELE C TRO- 7 'HERA FEU TICS.

constitute it the most powerful muscle of the whole body. It is protected from friction against other organs by a smooth serous membrane or sac containing cardiacal fluid, and this sac is spread over the whole surface of the heart, and so doubled on itself as to form a close bag, called the pericardium, or heart-case.

The heart itself is divided internally in the direction of its length into two halves, which, though so closely connected as to form one, constitute it in reality a double organ. Each part also being called upon to perform different functions from the other, the walls of each side differ in thickness in proportion to their uses. Thus, the right side (the office of which is simply to receive the blood and propel it with moderate force into the lungs) exhibits muscular walls less thick, and valves less elaborately fashioned than the left, through which the blood is received from the lungs, and propelled by the aortal artery through the whole body.

There are four principal cavities in the heart, the first two of which are termed auricles, situated on each side, right and left, though not exactly uniform, and two other cavities termed ventricles, both right and left of the heart, though less uniform even than the auricles. The auricles perform the part of receivers, the ventricles that of propellers.

Between each cavity there is a beautifully constructed valve, the duty of which is to permit the flow of blood in one direction, but to prevent its return again through the same orifice.

The auricle on the right side is furnished with a threepointed valve, called tricuspid, and that on the left

VALVES OF THE HEART.

with a two-pointed valve, termed bicuspid. Both these membranes are attached to the walls of the heart by little muscular cords, and though they appear to be merely finely attenuated threads, they are fashioned, like the valves, with an extraordinary amount of strength and resisting power.

Besides the auricular valves, there are two sets communicating between the ventricles and the arteries. These are termed semilunar valves, and their office is to afford passage from the ventricles to the arteries : the right ventricle forcing the blood into the pulmonary artery, and from thence through the lungs, and the left ventricle by the great aorta throughout the whole body.

In order to gain a correct idea of the course in which the tidal currents of the blood are projected, it is necessary to have a starting-point; and this we shall find by commencing to trace the circuit from the left ventricle. Remember always that the blood does not flow in regular channels through the heart, but that it is propelled by a strong impulse through each valve into its separate cavity. In the left ventricle we find the blood in that bright scarlet condition peculiar to the arterial flow. If we should pierce a vein in any part of the living structure, we shall observe a moderate but by no means impulsive flow of the contained fluid ; but if we should sever an artery, a violent upward rush of the blood will testify to the momentum with which the current has been impelled. This impulse is originated by the muscular contraction peculiar to the left ventricular cavity, which forces the blood with immense power

ELEC 7 'A' (9- THERA PE U TICS.

through the large arterial tube crowning the broad base of the heart, called the aorta. Directly after receiving the first flow of the arterial fluid, the aorta divides like an arch to the right and left, and again subdivides into four main trunks, — two branches of which extend upwards, when they are called the carotid arteries, and supply the different portions of the throat and head, the other two trunks tend downwards, and branch off on either side of the body into a complex system of tubing, ending in an inextricable net-work of fine hair-like passages called capillaries. The ramifications of this extensive system of vessels are supposed to extend in length to several miles, and it is thus that arterial blood is furnished to the body, supplying the entire system with nutrition and the life-giving oxygen inhaled through the lungs.

In the capillaries, -the blood parts with its nutritive qualities, and from thence it is taken up by the veins, the extent and ramifications of which correspond in all respects with the arteries, only that its dark purple, almost black, hue, denotes the absence of the vitalizing elements found in the arteries ; but it must be remembered that the chief office of the veins is to carry the blood back again to the great central reservoir of circulatory power in the heart. This they effect by being distributed side by side with the arteries, — intersecting them in thousands of yards of fine hair-like tubing, until they expand into larger proportions, and finally concentrate into four main trunks about the heart, corresponding to the position of the arteries. The large trunks which carry back the venous blood from the

6' VS TEMIC CIRC (J LA TION.

heart and throat are called the jugular veins, and the branches which return the blood from the trunk and extremities are termed vense cavse. Through these the blood is emptied into the right auricle, and from thence through the tricuspid valve into the right ventricle. Here what is called the great systemic circulation ends, and here the pulmonary or lesser circulation commences ; for it must be remembered that we started on our analysis by tracing the blood from the left ventricle, but before it can reach this point there must intervene that complete pulmonary circuit through the lungs to which we have previously called attention. The object of this lesser system of circulation is, as before stated, to expose the blood to the oxygen inhaled by the act of respiration, and thus to effect that radical change that converts the dark venous flow into the healthful and vitalizing condition of arterial blood.

The wonders of the circulatory system, and the effects of health or disease which result from a thorough understanding of its influence, cannot of course be fully appreciated from the condensed description which is herewith presented. It is enough to say, however, that if, as the best informed physiologists allow, a single grain of poison infused into any given portion of the organism will traverse the whole circulatory extent of tubing in something less than three minutes of time, what an array of poisonous elements are we not .perpetually introducing into our systems, in the shape of vitiated airs, fermented liquors, and other injurious articles of food, in the ignorant and unphysio-

ELEC 7 'R 0- THERA PE U TICS.

logical modes in which nine-tenths of the community pass their lives !

We now add a brief sketch of the methods by which food is prepared for the nourishment of the system through the digestive apparatus.

The organs of digestion commence with the teeth, and include the mouth, salivary glands, oesophagus, or food-pipe, the stomach, duodenum, or entrance to the small intestine, the pancreas, liver, gall-bladder, and lacteals.

The three kinds of teeth found in the human jaw are called incisors, canine, and molars. The first of these are designed simply to divide the food, the second to tear it, and the third to bruise or grind it. There are two sets of teeth, namely, the milk-teeth, which supply the gums of infancy and childhood, and the permanent teeth, which take the place of the others, from about the age of six to eight years.

The extreme hardness, diverse fashion, and separate offices performed by the three varieties of teeth fastened into the human jaw, taken in connection with similarly diverse functions performed by other portions of the digestive apparatus, demonstrate the food designed to sustain man should be of a mixed character, and include animal, vegetable, and cereal productions.

Besides the act of mastication, another important process takes place in the mouth, and this consists of insalivation, or the moistening and preparing the food for swallowing by the mixture of saliva. This fluid is secreted from three different sets of glands : the one

SALIVARY GLANDS.

pair situated just below each ear, and called the parotid glands ; the other pair placed beneath the tongue, called sublingual ; and the third, or submaxillary, placed near the angles of the lower jaw.

The fluids secreted from these three sets of glands differ in character, but in combination form saliva. A certain portion of saliva is always found in the mouth, except its flow is restrained by disease, but, like the gastric juice of the stomach, the moment food is presented to the mouth the flow is greatly increased, and sometimes occurs even when the thought of food excites the nerves which supply the salivary glands ; this result is known in what is vulgarly called “ setting the mouth watering” at the sight or mention of desirable food. After the food has been duly masticated and moistened by the saliva, it is collected by the muscles of the cheeks and the action of the tongue, and conveyed against the back part or vail of the palate, which is so hung as to close the cavity of the mouth in rest, yet in swallowing to open it freely and permit the passage of the food into the pharynx.

The oesophagus is an elastic muscular tube resembling the trachea in construction, inclosed on its external surface by a serous membrane ; then follows a layer of thick elastic muscular membrane, the whole being lined with mucous membrane.

By the muscular contractions of the oesophagus, the food is next forced through an orifice near the heart, surrounded with a strong band, or sphincter, into the main digestive cavity, or stomach.

The human stomach is an oblong membraneous bag,

3°

ELECTRO- THERAPEUTICS.

situated just below the diaphragm, and placed somewhat obliquely across the abdomen. It has two orifices : the one just alluded to, namely, the cardiac orifice, by which the food is received, and the other at its smaller extremity, called the pyloric orifice, the office of which is to convey the semi-digested food from the stomach into the intestines. Both these orifices are surrounded with muscular bands, which close upon the interior sac, and only open or expand when it is essential to receive or expel the food from the cavity of the stomach.