THE VAST NUMBER of facts and observations, by which the recent progress of scientific and practical medicine has been marked, is diffusely recorded in the Transactions of learned societies, in journals, in monographs, and in systematic treatises. With progress so rapid, and information so diffused, it is extremely difficult alike for the practitioner, the teacher, and the student to keep pace. It was the perception of this difficulty which induced the Editor, when invited to undertake the production of a new Medical Dictionary, to engage in a task which, he was fully conscious, must be one of great labour and of great responsibility. He felt, however, that he would be rendering useful service to his profession if he could bring together the latest and most complete information in a form which would allow of ready and easy reference. Accordingly, he invited the co-operation of certain of his colleagues and professional friends, both in this country and abroad; and evidence of the readiness with which this invitation has been accepted, is afforded by the list of contributors. Each contributor volunteered or was invited to write on a subject with which he was specially familiar. The present work, which is the result of these combined efforts, may therefore be regarded not only as a dictionary, but also as a treatise on systematic medicine, in which the articles on the more important subjects constitute monographs in themselves, whilst definitions and descriptions of matters having less claim to extended notice are given as fully as is required. Thus an endeavour has been made to supply, in a clear, condensed, and readily accessible form, all the informtion that is at present available for the use of the practitioner of medicine.

As indicated on the title-page, the work is primarily a dictionary of Medicine, in which the several diseases are fully discussed in alphabetical order. The description of each includes an account of its ætiology and anatomical characters; its symptoms, course, duration, and terminations; its diagnosis, prognosis, and, lastly, its treatment. General Pathology comprehends articles on the origin, characters, and nature of disease, and the many considerations which these topics suggest. General Therapeutics will be found to include articles on the several classes or remedies--medicinal or otherwise--which are available for the purpose of treatment; on the modes of action of such remedies; and on the methods of their use. The articles devoted to the subject of Hygiene will be found to treat of the causes of disease, of its prevention, of the agencies and laws affecting public health, of the means of preserving the health of the individual, of the construction and management of hospitals, and of the nursing the sick. Lastly, the diseases peculiar to Women and Children are discussed under their respective headings, both in aggregate and in detail.

It may be well to explain that, although it has been found necessary to include some notice of diseases which fall more generally under the care of the surgeon, the work does not pretend to be a dictionary of Surgery; and also that, although certain drugs are enumerated in discussing subjects of general therapeutics, and of poisons and their actions, there has been no intention to invade the domain of Materia Medica.

It is right to observe that all the articles have been edited and revised with great care, so as to ensure a completeness and unity in the work, which it is not always possible to obtain in books composed by a number of writers.

The Editor desires also to state that, although the work has occupied several years in preparation, arrangements were made with the printers which have enabled him to revise every article which required revision, up to the time of going to press. Further, by the addition of an Appendix it has been possible to incorporate the latest contributions to medical knowledge.

Having thus set forth the aims and objects of his undertaking, and how far they have been carried out, the Editor has the great satisfaction of offering his thanks to his friends and colleagues, for the valuable assitance which he has received from them. He is fully conscious of the trouble which must often have been necessary in order to condense extended knowledge of a familiar subject within the limited space which the nature of this work could afford.

The Editor has further the pleasing duty of offering his special thanks to DR. FREDERICK T. ROBERTS and to DR. J. MITCHELL BRUCE, who from the first have been his Assistant-editors and fellow-labourers. Without the help which they have afforded him, it would have been impossible for him to have fulfilled the duties which he undertook. He is well aware of the time and labour which their assitance has involved; and he appreciates most fully the marked ability by which it has been characterised.

The Editor cannot conclude without a reference to some of those who were his friends and colleagues when this work was commenced, but who have since been taken away by death. He would specially mention the names of EDMUND PARKES, CHARLES MURCHISON, GEORGE CALLENDER, THOMAS BEVILL PEACOCK, JOHN ROSE CORMACK, LOCKHART CLARKE, TILBURY FOX, THOMAS HAYDEN, HARRY LEACH, ALEXANDER SILVER. The loss of these eminent men, many of them dear and valued friends, and all of them taken too soon from their unfinished labours, is to him a source of personal sorrow. The articles written by them for these pages were in most instances their last contributions to medical literature, and will be valued accordingly.

LONDON, September 1882.

ABDOMEN, Diseases of the.--Before entering upon the study of the particular diseases which are liable to be met with in connexion with each of the principal regions of the body, it is expedient to regard them from a general point of view, as such a course helps materially in clearing the way for their clinical investigation. This general survey is particularly advantageous in the case of abdominal diseases, which are necessarily very numerous and varied, both as regards the structure affected and the nature of the morbid change they present; they are consequently difficult to recognise with certainty in many instances, and are occasionally involved in much obscurity.

Excluding a few peculiar affections, the diseases of the abdomen may be arranged under the following groups:--

I. Diseases of the anterior abdominal walls.

II. Diseases of the peritoneum and its folds.

III. Diseases of the organs contained within the abdominal cavity, namely:--
1. Stomach and Intestines;
2. Hepatic organs, including the liver, gall-bladder, and gall-ducts;
3. Spleen;
4. Pancreas;
5. Supra-renal capsules;
6. Urinary apparatus, viz., the kidneys and their ducts, and the bladder;
7. Female generative organs, including the uterus and its broad ligaments, the Fallopian tubes, and the ovaries;
8. Absorbent glands.

IV. Diseases of the abdominal vessels, especially the aorta and the iliac arteries.

V. Diseases of the sympathetic or other nerves contained within the abdomen.

VI. Diseases originating in connexion with the cellular tissue, such as inflammation or abscess.

VII. Diseases springing from the posterior boundary of the abdomen; from the pelvis or the structures lining it; or from the diaphragm, and invading the abdominal cavity.

VIII. Diseases encroaching upon the abdomen from other parts, especially from the thorax.

It must be borne in mind that the groups of diseases above-mentioned may be presented in various combinations, two or more structures being not uncommonly implicated at the same time.

The special nature and mode of origin of the diseases thus summarised will be discussed under their appropriate headings, but a few general observations on this subject may prove serviceable. Several of the abdominal organs are very liable to so-called functional disorders, being much exposed to the repeated action of various disturbing influences and these disorders often give rise to prominent and troublesome symptoms, which are urgently complained of by the patient. Definite organic diseases are also of common occurrence, many of them being of a very serious character. Some of the organs contained within the abdomen are subject to malposition or displacement, as well as to malformations, these being either congenital or acquired; while the hollow viscera may be the seat of obstruction or accumulations of different kinds; and each of these conditions may become clinically important.

Abdominal lesions are frequently purely local in their origin, but several of them are but local manifestations of some general condition, being either associated with certain acute febrile diseases, e.g., thyphoid fever; or with some constitutional cachexia, such as cancer. Again, symptoms connected with the abdomen may depend upon disease in some remote part of the body, or some of its organs may become the seat of morbid changes as a consequence of disease in other structures. For instance, vomiting is frequently associated with cerebral disorders; while affections of the heart are liable to lead to troublesome symptoms, as well as to serious lesions in connexion with many of the abdominal viscera. Lastly, a morbid condition of one organ within the abdomen may be the direct means of originating secondary mischief in other structures.

CLINICAL INVESTIGATION.-- The clinical examination of cases in which the symptoms point to the abdomen as the seat of mischief should always be conducted with particular care and thoroughness, as well as in a systematic manner, otherwise serious mistakes are liable to be made. It is also very desirable to avoid forming any definite conclusion as to the nature of the complaint hastily or on insufficient data, but rather to wait and observe the course of events in any doubtful case, repeating the investigation from time to time, when any obscurity which may exist will often be cleared away. The past and family history of the patient, with the course and progress of the symptoms, are often of material assistance in diagnosis, and demand due attention in every instance. The chief clinical phenomena which may be associated with abdominal affections, and with reference to which it is requisite to inquire, may be thus indicated. First, there are usually symptoms directly connected with the structure implicated, such as pain and other morbid sensations, disorders of secretory or other functions, or excited action. Secondly, several of the organs mutually affect each other, either from being anatomically or physiologically related, or from a morbid condition of one part causing pressure upon or irritation of some neighbouring structure. In this way numerous symptoms are liable to arise, sometimes in remote parts, and often of material significance. Thirdly, sympathetic or reflex phenomena in connexion with organs in other regions of the body are frequently excited by many abdominal disorders, such as palpitation of the heart, convulsions, and other nervous disturbances. Fourthly, the general system often suffers seriously, and in various ways. For instance, pyrexia may be excited; the blood may become impoverished or impregnated with noxious materials; or more or less general wasting and debility may be induced. Where an abdominal disease is but a local manifestation of some constitutional condition, it commonly aggravates materially the general symptoms; while in connexion with lesions of certain of the abdominal viscera these general symptoms constitute in many cases the most prominent clinical features. Fifthly, morbid conditions within the abdomen not unfrequently interfere directly with the diaphragm and the thoracic organs; occasionally also they invade upon the chest, or actually make their way into this cavity through the diaphragm. In rare instances morbid products, such as pus, may find their way to distant parts of the body. In these different ways a variety of symptoms may be caused, sometimes of a curious nature and difficult to explain. Lastly, abdominal diseases are frequently attended with abnormal physical or objective signs, which are revealed on physical examination, and these are of such importance that they demand separate consideration.

PHYSICAL EXAMINATION.-- The neglect of submitting patients to a satisfactory physical examination is a frequent source of error in diagnosis in cases of abdominal disease, and there ought to be no hesitation or delay in resorting to this method of clinical investigation whenever it seems called for. The precise course to be pursued must vary according to circumstances, but the following outline will serve to indicate the plan of procedure ordinarily required.

First, there are certain modes of examination which are applied to the abdomen externally, including Inspection; Palpation or Manipulation; Mensuration or Measurement; Percussion; and Auscultation (see PHYSICAL EXAMINATION). Of these, inspection, palpation, and percussion are by far the most important, and have, in the large majority of cases, to be relied upon for the information required. In exceptional instances Succussion or shaking the patient proves serviceable, by bringing out certain sensations or sounds. In order to carry out these methods properly, it is necessary to expose the abdomen sufficiently, due regard being paid to decency in the examination of females; to place the patient in a suitable position; and to see that the muscles of the abdominal walls are duly relaxed. The best position usually is for the patient to lie on the back, in a half-reclining attitude, with the head and shoulders well raised, and the thighs and knees more or less flexed. This posture serves to relax the abdominal muscles, which may be further aided by taking off the patient's attention by conversation or in other ways, as well as by directing him to breathe deeply. The position, however, has often to be varied in the investigation of particular cases, and much information is frequently gained by noticing the effects of altering the posture.

The objective conditions which may be revealed by the modes of examination thus far considered are as follows:
1. The state of the superficial structures.
2. The size and shape of the abdomen, generally and locally, as indicating an alteration in the volume of the ordinary contents of the abdomen, or the presence of some new or fresh element, such as dropsical fluid or a tumour.
3. The characters of the abdominal respiratory movements; and the presence of any unusual sensations during the act of breathing, such as friction-fremitus.
4. The sensations experienced on palpation and percussion over the abdomen, either as a whole, or in any particular part of it, such as its mobility, degree of resistance, regularity, consistence, &c.; as well as the presence of certain peculiar sensations, e.g., fluctuation, or hydatid-fremitus.
5. The presence and characters of any pulsation.
6. The occurrence of abnormal movements within the abdomen, as those of a foetus.
7. The sounds elicited, generally and locally, on percussion.
8. The presence of certain sounds within the abdomen, heard on auscultation, such as friction-sounds; murmurs connected with aneurism or due to pressure on an artery; or murmurs and sounds associated with the pregnant uterus.

Secondly, it not uncommonly happens that special modes of examination have to be applied to particular organs within the abdomen, in order to arrive at a diagnosis with any certainty. And here it may be remarked that it is highly important in all cases to see that no accumulation of fæces exists within the bowels, and that the bladder is properly emptied, otherwise very serious mistakes are liable to be made. Purgatives and enemata are needed in order to remove any fæcal collection. The urine should also be properly tested in every instance; and much information may often be gained in the investigation of affections of the alimentary canal, from a personal inspection or more complete examination of fæces or vomited matters. The abdominal organs to which special modes of examination are chiefly applicable are the female generative organs, which are investigated per vaginam (see WOMB, Diseases of); the bladder, by means of the catheter, the sound, and other surgical instruments; the stomach, by the use of the stomach-pump, probang, &c.; and the intestines, by examining with the finger, hand, or surgical instruments per rectum, or by injecting water or air through the anus into the bowels. The ordinary modes of examination already mentioned may afford assistance when employed along with some of the special methods just indicated.

Thirdly, occasionally it is requisite to have recourse to exceptional modes of investigation, such as the use of the exploring trochar or aspirator; or to the adminstration of chloroform. The latter may afford direct information in certain abdominal conditions, and it may also materially assist in carrying out other methods of exploration.

The abnormal conditions discoverable by physical examination may involve the entire abdomen, giving rise, for instance, to general enlargement or retraction; or they may be limited to some particular region; e.g., enlarged organs, tumours, or abscesses. This part of the body has been artificially divided by anatomists into regions, and the seat of any local morbid condition can thus be defined and described. The diseases peculiar to the several regions will be considered under their respective headings.

FREDERICK T. ROBERTS.

ABDOMINAL ANEURISM includes aneurism of the aorta, and of any of its branches within the abdomen.

Aneurism of the Abdominal Aorta is essentially a disease of middle age. Of fifty-nine cases collected by Dr. Crisp, thirty-three were under the age of forty. It is more common in the male than in the female sex in the proportion of about 8 : 1; and is usually traceable to strain, or to a blow upon the abdomen or back. The aneurism is most frequently located in that portion of the vessel included between the aortic opening in the diaphragm and the origin of the superior mesenteric artery. In this situation the tumour is deeply seated; liable to tension from the crura of the diaphragm; and likely to involve the great splanchnic nerves, the semilunar ganglia, and the solar plexus. Hence the occasional difficulty of diagnosis; and the frequency of boring pain in the back from erosion of the vertebræ, and of paroxisms of radiating pain in the abdominal viscera from stretching of the adjacent nerves. When situated lower down in the course of the aorta, the disease is less obscure, and the symptoms are less urgent. Aneurism of the abdominal aorta is usually of the false variety; and, as contrasted with thoracic aneurism, it is less often associated with extensive atheroma of the aorta, and with fatty or other structural disease of the heart. The symptoms referable to excentric pressure are also fewer, and, with the exception of pain, are less urgent.

SYMPTOMS AND SIGNS.--Of the symptoms, pain is the most characteristic and the most urgent; it is of two kinds, which are not, however, necessarily associated. In its usual form the pain of abdominal aneurism is essentially neuralgic; it is intermittent and paroxysmal,--radiating through the abdomen, back, pelvis, and base of the thorax, and not unfrequently into either groin or testicle. The accession is sudden, and usually attributable to some definite cause of vascular excitement. The duration extends over a period varying from one to three hours, rarely longer; and the cessation is equally abrupt, leaving the patient in a state of exhaustion, but quite free from actual suffering. The second kind of pain referred to is continuous and boring; fixed at a particular point of the vertebral column; aggravated by pressure at this point, by active movement or stamping, and by gently turning the patient half round upon his axis in the standing posture; but relieved by anti-recumbency or leaning forward. Pain so characterised is pathognomonic of erosion of the vertebræ. Pressure of an aneurism may affect the functions of several organs within the abdomen. Thus jaundice may result from pressure upon the hepatic or common biliary duct: it is, however, more frequently due to an aneurism of the hepatic or of the superior mesenteric artery. Interference with the urinary secretion, and the consequences thereof, from pressure upon the renal vessels; dysphagia from pressure upon the oesophagus; vomiting from obstruction of the pylorus; displacement of the liver forwards, or of the heart upwards--though rare symptoms--may be likewise due to the same cause. The radial pulse is not often affected. Symptoms of constitutional irritation and impaired nutrition are rarely exhibited, and appear only at the termination of protracted and painful cases, associated with great suffering and want of sleep.

The physical signs are those discoverable by palpation, percussion, and auscultation. The tumour usually projects to the left of the mesial line, and tends to descend; it is smooth and elastic; communicating to the hand alternate movements of lifting and expansion with increasing tension, and of subsidence with relaxation. The pulsation is all but invariably single, and synchronous with the radial pulse; it is limited to the tumour, and occasionally accompanied by thrill. Pressure upon the aorta below the tumour will increase the force of impulse, diminish or abolish the thrill, and arrest the collapse. In a few recorded examples the tumour was hard and uneven on the surface, and non-expansile; and in a still smaller number no pulsation was perceptible, the aperture of communication with the artery having been blocked, or the vessel compressed on the proximal side by the growth of the aneurism itself. Owing to the position of the hollow viscera in front, and the mass of lumbar muscles behind, the evidence from percusion is less conclusive in regard to abdominal than thoracic aneurism. If, however, the abdominal muscles be relaxed, and the stomach and bowels free from flatus, absolute dulness to the extent of the tumour may be detected. A sound, single or double, as distinguished from murmur, is rarely heard in front in connexion with abdominal aneurism; whereas the existence of sound without murmur, and usually double, at a point of the posterior wall of the abdomen corresponding to the tumour, is the rule, and, when detected, is of the utmost diagnostic value. Murmur in the recumbent posture is rarely absent in front; it is single, blowing, prolonged, post-systolic, and not transmitted into the vessel beyond. It may, however, be musical, or it may present both these characters, but at different points of the tumour; in one instance it was of a buzzing quality. Should the aneurism have taken an exclusively backward course, which is the exception, a single murmur, not audible in front, may be heard in the back. In a few recorded cases a double murmur has been heard over the aneurism in front. In the erect posture the murmur is usually suspended; but in a few published cases it was audible in both the erect and the recumbent posture, and in one at least in the erect posture only. These peculiarities depend upon the various conditions of the sac, its orifice, and its contents. A small aneurism engaging the posterior wall of the vessel only, and eroding the vertebræ, may be latent as to physical signs, though attended with severe fixed pain in the back.

DIAGNOSIS.--The diagnosis of abdominal aneurism has reference mainly to its physical signs. Strong pulsation of the aorta, simulating that of aneurism, may exist in connexion with hysteria, uterine or intestinal irritation, dyspepsia, or copious hæmorrhage. But in all these cases, irrespectively of the positive and specific evidence presented by each, throbbing exists throughout the aorta, and is propagated into the main arteries of the lower limbs, whereas it is localised in aneurism; and a careful exploration of the aorta, if necessary under the influence of chloroform, will show that its dimensions are at all points normal. In these cases, too, although a murmur may be produced by strong pressure with the stethoscope, it does not exist when pressure is withdrawn. A cancerous or other tumour pressing upon the aorta may likewise produce murmur, and may exhibit pulsation communicated from the aorta; but in most cases both these phenomena are promptly arrested by placing the body in the prone position; the tumour, in that position, gravitating from the vessel. The fixed local pain in the back, aggravated by pressure and motion, may be simulated by spinal rheumatism; and the paroxysmal visceral pain by biliary colic. The differential diagnosis must rest upon the specific evidence in each case, and upon the absence of the signs of aneurism.

Aneurism of the Branches of the Abdominal Aorta.--The branches most liable to aneurism are the common iliacs and their divisions; the coeliac axis and its branches; the renal and the superior mesenteric. Aneurism of the Iliac Arteries belongs to the domain of surgery, and will not be further referred to here. Aneurism of the Coeliac Axis and of its branches of division, and of the Superior Mesenteric Artery, are, in addition to the ordinary signs, equally characterized by mobility; and the first two varieties by jaundice, hæmatemesis, and melæna, from pressure. Renal aneurism may cause obstruction in the kidney or renal colic by pressure on the structures in the hilus.

DURATION AND TERMINATION.--The duration of life in cases of abdominal aneurism has, in the writer's experience, varied from fifteen days to eleven years. Death occurs usually (1) by rupture of the sac into (a) the retro-peritoneal tissue; (b) the cavity of the peritoneum; (c) the left pleura or lung; (d) the intestinal canal; (e) the inferior cava; (f) the psoas muscle; (g) the pelvis of the kidney; (h) the spinal canal; or (i) the ureter, biliary passages, or oesophagus; and in the order of relative frequency just given; or (2) by exhaustion or syncope. The duration of life after the rupture of the aneurism has ranged from a few minutes to several weeks. A consecutive false aneurism of the retro-peritoneum is specially characterised by feeble pulsation of the tumour, and diminished or arrested circulation in the femoral artery of one or both sides.

TREATMENT.--The Curative treatment of abdominal aneurism may be considered under three heads--Mechanical, Postural and Dietetic, and Medicinal. Mechanical treatment consists in pressure applied to the aorta on the proximal side of the sac, or simultaneously on its proximal and distal sides, by means of tourniquets, so as completely to stop the circulation. The bowels should be first well moved and freed from flatus; and during the continuance of pressure the patient should be kept under the influence of chloroform or ether. Five cases, if not more, in which a cure was affected by these means have been reported. The object sought to be attained being that of effecting rapid coagulation in the sac, the period during which pressure needs to be continued in these cases varies from three quarters of an hour to ten hours and a half. Where space for the application of proximal pressure does not exist, distal pressure alone may be tried. Under all circumstances, pressure must be used with circumspection, as inflammation of the peritoneum or of the bowels may result from it.

Billingham introduced the plan of treatment by posture and restricted diet. Under this plan perfect repose of mind and body is, as far as practicable to be maintained; the bowels being kept moderately free, and the dietary restricted to 10 oz. of solids and 6 oz. of liquids daily. According to the method of Mr. Tufnell, which is based upon the same principle, but is more rigid, the patient is strictly confined to the horizontal posture for a period varying from eight to thirteen weeks, as determined by the effect upon the aneurism, movement in bed being affected with caution; whilst, by a special arrangement, the bowels and the bladder may be evacuated without disturbance of the body. For breakfast, 2 oz. of white bread and butter, with 2 oz. of cocoa or milk, are allowed; for dinner, 3 oz. of meat, with 3 oz. of potatoes or bread, and 4 oz. of water or claret; and for supper, 2 oz. of bread and butter, and 2 oz. of milk or tea. The total amount in the twenty-four hours would be, solids 10 oz., liquid 8 oz. This system might be in some degree relaxed if the patient prove restive. Mild laxatives and opiates as required are the only medicines used. Ten cases of the successful treatment of aortic aneurism by this method have been reported by Mr. Tufnell. Abdominal aneurism was solidified in two instances, after treatment extending over thirty-seven and twenty-one days respectively.

Of the various medicinal agents used with a view to favouring or affecting a deposit of laminated fibrin in the sac, acetate of lead, iodide of potassium, aconite, and ergotin (hypodermically), alone claim attention. Iodide of potassium may be given with advantage in doses of 10 to 20 grs. thrice daily, with a view to reducing vascular tension, and thereby relieving pain and promoting deposition in the sac, whilst perfect rest in the recumbent posture and a restricted dietary are observed. The latter are, however, the more important factors in the treatment. Dr. G. W. Balfour has reported several cases successfully treated by means of iodide of potassium; and recently an example of a similar kind has been published by Dr. Dyce Duckworth. Dr. Grimshaw has lately had an example of cure mainly through the use of aconite. At the same time the allowance of liquids must be reduced to the lowest possible standard, whilst excretion is promoted. Alcoholic stimulants may be given in small quantity and at long intervals, if the pulse exhibit debility and the patient complain of a sensation of sinking; otherwise they should be prohibited.

The Palliative treatment as applied to Abdominal Aneurism will be found described in the article AORTA, Disease of (Aneurism). The application of a few leeches, followed by a warm poultice, is very efficacious in relieving pain. The hypodermic use of morphia is still more rapidly effective.

THOMAS HAYDEN.

ABDOMINAL TYPHUS--A synonym for Typhoid Fever. See TYPHOID FEVER.

ABDOMINAL WALLS, Diseases of.
But little more will be needed in this article than to give a brief outline of the nature of the affections to which the abdominal walls are liable, as most of these are but local forms of diseases which are fully described in other parts of this work. The parietal peritoneum will be excluded from consideration, as its morbid conditions are treated of separately.

1. SUPERFICIAL AFFECTIONS.
a. The skin covering the abdomen may be the seat of various eruptions. The rash of typhoid fever is chiefly observed over this region.
b. When the abdomen is greatly enlarged, its cutaneous covering becomes stretched and thinned, often presenting a shining appearance: this may even give way, so that it exhibits superficial cracks or fissures. If it has been distended for a considerable time or on several occasions, as after repeated pregnancies, the skin becomes impaired in its structure and is often the seat of permanent white lines or furrows--lineæ alibicantes. In this connection alIusion may be made to the umbilicus, which, in certain forms of distension of the abdomen, may become pouched out, everted, or actually obliterated.
c. The veins of the skin frequently become enlarged and tortuous, when the return of the blood which is normally conveyed through them is in any way impeded. The particular vessels which are distended will necessarily depend upon the seat of the obstruction.
d. The cutaneous sensibility over the abdomen is sometimes materially altered. In certain nervous diseases it may become more or less impaired or lost; but the most important deviation is a marked increase of sensibility--hyperæthesia--which is occasionally observed in hysterical females, and which may simulate more seriouss affections, particularly peritonitis, especially if it is accompanied with symptoms of much depression. This condition is characterised by extreme superficial sensibility or tenderness of the abdomen, the slightest touch being resented; but if the patient's attention can be taken off, and deep pressure be then made, this is borne with little or no indication of distress. The aspect of the patient, the presence of other symptoms indicative of hysteria, and the absence of pyrexia, usually serve to distinguish this affection from others of a graver nature. The surface of the abdomen may also be affected with neuralgia, which is sometimes very severe.

2. SUBCUTANEOUS ACCUMULATIONS.
a. The chief morbid condition coming under this head is oedema or dropsy of the subcutaneous tissue. This generally follows anasarca of the legs, and may be associated with ascites. The fluid tends to collect especially in the lower part of the abdominal walls and towards the flanks. The skin often presents a white pasty aspect; the abdomen may be more or less enlarged; the umbilicus appears depressed and sunken, if the oedema extends up to this level; the superficial structures pit on pressure, and yield the peculiar sensation of dropsical tissues; and the percussion note is frequently muffled.
b. The abdominal subcutaneous tissue is, in many persons, the seat of an abundant collection of fat, which may be important from its causing general enlargement, and simulating or obscuring other more serious morbid conditions which enlarge the abdomen.

3. AFFECTIONS OF THE MUSCLES AND APONEUROSES.
a. The abdominal walls maybe the seat of muscular rheumatism, which is particularly likely to follow undue straining, such as that caused by violent coughing or vomiting. It is characterised by pain, sometimes severe, evidently located in the muscular and tendinous structures, accompanied with much soreness and tenderness. The affected parts are kept as much at rest as possible, and any action which disturbs them materially aggravates the pain.
b. As the result of violent strain, the muscular or aponeurotic tissues may be more or less torn or ruptured. As a consequence a protrusion of some internal structure may take place, forming a hernia.
c. The abdominal muscles are liable to be the seat of spasmodic contractions, cramp, or rigidity. These are not uncommonly excited in sympathy with grave disturbance of the alimentary canal, as in cholera. In certain painful internal affections also some of the abdominal muscles are occasionally kept in a state of more or less rigid tension, as if they were involuntarily contracted in order to protect the diseased parts underneath from injury. The spasmodic contractions in tetanus not unfrequently cause great suffering over the abdomen.
d. On the other hand, the abdominal muscles are occasionally paralyzed, as the result of centric nervous disease. The movements of respiration are then altered in character; while the expulsive acts in which the abdominal muscles naturally take part are much interfered with.

4. RELAXED ABDOMINAL WALLS.--AIl the structures forming the walls of the abdomen are often in a relaxed and flabby state, yielding to any pressure from within, so that the abdomen becomes enlarged and prominent, especially if,