The treatment of ruptured gastric ulcer demands immediate operation. An incision should be made in the upper part of the middle line of the abdomen, and the perforation should be looked for. There is not, as a rule, much difficulty in finding it, as there are generally deposits of lymph near the spot, and other signs of local inflammation; moreover, the contents of the stomach may be seen escaping from the opening. The ulcer is to be closed by running a "purse-string" suture in the healthy tissue around it, and the place is then buried in the stomach by picking up small folds of the stomach-wall above and below it and fixing them together by suturing. This being done, the surface of the stomach, and the neighbouring viscera which have been soiled by the leakage, are wiped clean and the abdominal wound is closed, provision being made for efficient drainage. A large proportion of cases of perforated gastric ulcer thus treated recover. (E. O.*)

of the food, as well as to the irritation of the inflamed nerve | done, death from the septic poisoning of peritonitis is almost filaments in the floor of the ulcer. Vomiting is a usual symptom. certain. It occurs either soon after the food is swallowed or at a later period, and generally relieves the pain and discomfort. Vomiting of blood (haematemesis) is a frequent and important symptom. The blood may show itself in the form of a brown or coffee-like mixture, or as pure blood of dark colour and containing clots. It comes from some vessel or vessels which the ulcerative process has ruptured. Blood is also found mixed with the discharges from the bowels, rendering them dark or tarry-looking. The general condition of the patient with gastric ulcer is, as a rule, that of extreme ill-health, with pallor, emaciation and debility. The tongue is red, and there is usually constipation. In most of the cases the disease is chronic, lasting for months or years; and in those cases where the ulcers are large or multiple, incomplete healing may take place, relapses occurring from time to time. But the ulcers may give rise to no marked symptoms, and there have been instances where fatal perforation suddenly took place, and where post-mortem examination revealed the existence of long-standing ulcers which had given rise to no suggestive symptoms. While gastric ulcer is to be regarded as dangerous, its termination, in the great majority of cases, is in recovery. It frequently, however, leaves the stomach in a delicate condition, necessitating the utmost care as regards diet, Occasionally the discase proves fatal by sudden haemorrhage, but a fatal result is more frequently due to perforation and the escape of the contents of the stomach into the peritoneal cavity, in which case death usually occurs in from twelve to forty-eight hours, either from shock or from peritonitis. Should the stomach become adherent to another organ, and fatal perforation be thus prevented, chronic "indigestion " may persist, owing to interference with the natural movements of the stomach. Stricture of the pylorus and consequent dilatation of the stomach may be caused by the cicatrization of an ulcer.

The patient should at once be sent to bed and kept there, and allowed for a while nothing stronger than milk and water or milk and lime water. But if bleeding has recently taken place no food whatever should be allowed by the stomach, and the feeding should be by nutrient enemata. As the symptoms quiet down, eggs may be given beaten up with milk, and later, bread and milk and home-made broths and soups. Thus the diet advances to chicken and vegetables rubbed through a sieve, to custard pudding and bread and butter. As regards medicines, iron is the most useful, but no pills of any sort should be given. Under the influence of rest and diet most gastric ulcers get well. The presence of healthy-looking scars upon the surface of the stomach, which are constantly found in operating upon the interior of the abdomen, or as revealed in post-mortem examinations, are evidence of the truth of this statement. It is unlikely that under the treatment just described perforation of the stomach will take place, and if the surgeon is called in to assist he will probably advise that operation is inadvisable. Moreover, he knows that if he should open the abdomen to search for an ulcer of the stomach he might fail to find it; more than that, his search might also be in vain if he opened the stomach itself and examined the interior. Serious haemorrhages, however, may make it necessary that a prompt and thorough search should be made in order that the surgeon may endeavour to locate the ulcer, and, having found it, secure the damaged vessel and save the patient from death by bleeding.

Perforation of a gastric ulcer having taken place, the septic germs, which were harmless whilst in the stomach, escape with the rest of the contents of the stomach into the general peritoncal cavity. The immediate effects of this leakage are sudden and severe pain in the upper part of the abdomen and a great shock to the system (collapse). The muscles of the abdominal wall become hard and resisting, and as peritonitis appears and the intestines are distended with gas, the abdomen is distended and becomes greatly increased in size and ceases to move, the respiratory movements being short and quick. At first, most likely, the temperature drops below normal, and the pulse quickens. Later, the temperature rises. If nothing is

GASTRITIS (Gr. yaorhp, stomach), an inflammatory affection of the stomach, of which the condition of catarrh, or irritation of its mucous membrane, is the most frequent and most readily recognized. This may exist in an acute or a chronic form, and depends upon some condition, either local or general, which produces a congested state of the circulation in the walls of the stomach (see DIGESTIVE ORGANS: Pathology).

Acute Gastritis may arise from various causes. The most intense forms of inflammation of the stomach are the toxic conditions which follow the swallowing of corrosive poisons, such as strong mineral acids of alkalis which may extensively destroy the mucous membrane. Other non-corrosive poisons cause acute degeneration of the stomach wall (see POISONS). Acute inflammatory conditions may be secondary to zymotic diseases such as diphtheria, pyaemia, typhus fever and others. Gastritis is also caused by the ingestion of food which has begun to decompose, or may result from eating unsuitable articles which themselves remain undigested and so excite acute catarrhal conditions. These give rise to the symptoms well known as characterizing an acute "bilious attack," consisting in loss of appetite, sickness or nausea, and headache, frontal or occipital, often accompanied with giddiness. The tongue is furred, the breath foetid, and there is pain or discomfort in the region of the stomach, with sour eructations, and frequently vomiting, first of food and then of bilious matter. An attack of this kind tends to subside in a few days, especially if the exciting cause be removed. Sometimes, however, the symptoms recur with such frequency as to lead to the more serious chronic form of the disease.

The treatment bears reference, in the first place, to any known source of irritation, which, if it exist, may be expelled by an emetic or purgative (except in cases due to poisoning). This, however, is seldom necessary, since vomiting is usually present. For the relief of sickness and pain the sucking of ice and counterirritation over the region of the stomach are of service. Further, remedies which exercise a soothing effect upon an irritable mucous membrane, such as bismuth or weak alkaline fluids, and along with these the use of a light milk diet, are usually sufficient to remove the symptoms.

Chronic Gastric Catarrh may result from the acute or may arise independently. It is not infrequently connected with antecedent disease in other organs, such as the Jungs, heart, liver or kidneys, and it is especially common in persons addicted to alcoholic excess. In this form the texture of the stomach is more altered than in the acute form, except in the toxic and febrile forms above referred to. It is permanently in a state of congestion, and its mucous membrane and muscular coat undergo thickening and other changes, which markedly affect the function of digestion. The symptoms are those of dyspepsia in an aggravated form (see DYSPEPSIA), of which discomfort and pain after food, with distension and frequently vomiting, are the chief; and the treatment must be conducted in reference to the causes giving rise to it. The careful regulation of the diet, alike as to the amount, the quality, and the intervals between meals, demands special attention. Feeding on artificially soured milk may in

many cases be useful. Lavage or washing out of the stomach with weak alkaline solutions has been used with marked success in the treatment of chronic gastritis. Of medicinal agents, bismuth, arsenic, nux vomica, and the mineral acids are all of acknowledged efficacy, as are also preparations of pepsin.

| the topographically right kidney. The transformation has been
actually shown to take place in the development of Paludina. In
apex to mouth, and the spiral also
a dextral Gastropod the shell is coiled in a right-handed spiral from
projects to the right of the median
A
B
plane of the animal.

GASTROPODA, the second of the five classes of animals
When the shell is sinistral the
constituting the phylum Mollusca. For a discussion of the re-reversed, and there is a complete situs
asymmetry of the organs is usually
lationship of the Gastropoda to the remaining classes of the
phylum, see MOLLUSCA.

The Gastropoda are mainly characterized by a loss of symmetry, produced by torsion of the visceral sac. This torsion may be resolved into two successive movements. The first is a ventral flexure in the antero-posterior or sagittal plane; the result of this is to approximate the two ends of the alimentary canal. In development, the openings of the mantle-cavity and the anus are always originally posterior; later they are brought forward ventrally. During this first movement flexure is also produced by the coiling of the visceral sac and shell; primitively the latter was bowl-shaped; but the ventral flexure, which brings together the two extremities of the digestive tube, gives the visceral sac the outline of a more or less acute cone. The shell necessarily takes this form also, and then becomes coiled in a dorsal or anterior plane-that is to say, it becomes exogastric. This condition may be seen in embryonic Patellidae, Fissurellidae and Trochidae (fig. 1, A), and agrees with the method of coiling of a mollusc without lateral torsion, such as Nautilus. But ultimately the coil becomes ventral or endogastric,

pa

a

pac

inversus viscerum, the direction of the
spiral of the shell corresponding to
the position of the organs of the
body. Triforis, Physa, Clausilia are
examples of sinistral Gastropods, but
reversal also occurs as an individual
variation among forms normally dex-
tral. But there are forms in which
the involution is " hyperstrophic,"
that is to say, the turns of the spire From Lankester's Treatise on Zoology.
projecting but slightly, the spire,
after flattening out gradually, finally development of a Gastropod
FIG. 2.-Four stages in the
becomes re-entrant and transformed showing the process of body
into a false umbilicus; at the same
time that part which corresponds to
torsion. (After Robert.)
the umbilicus of forms with a normal A,
coil projects and constitutes a false B,
spire; the coil thus appears to be
sinistral, although the asymmetry C,
remains dextral, and the coil of the
that of the shell) sinistral (e.g.
Lanistes among Streptoneura, Lima-
cinidae among Opisthobranchia). The a,
same, mutatis mutandis, may occur f,
in sinistral shells.

Embryo without flexure.
Embryo with ventral flex-
ure of the intestine.
Embryo with ventral flex-
ure and exogastric shell.
sion and an endogastric
shell.
Anus.

in consequence of the second torsion movement then apparent. operculum (always the opposite to D, Embryo with lateral tor

B, A stage 1 hours later than A.
C, A stage 3 hours later than B. ve,

The shell is represented as fixed, while the head and foot rotate from left to right. In reality the head and foot are fixed and the shell rotates from right to left.

Foot.

m, Mouth.

The problem of the causes of the pa, Mantle.
torsion of the Gastropod body has pac, Pallial cavity.
been much discussed. E. R. Lan- ve, Velum.
kester in the ninth edition of this

work attributed it to the pressure of the shell and visceral hump
towards the right side. He referred also to the nautiloid shell of
the larva falling to one side. But these are two distinct processes.
In the larva a nautiloid shell is developed which is coiled exo-
gastrically, that is, dorsally, and the pallial cavity is posterior or
ventral (fig. 2. C): the larva therefore resembles Nautilus in the
relations of body and shell. The shell then rotates towards the left
side through 180°, so that it becomes ventral or endogastric (fig. 2,
D). The pallial cavity, with its organs, is by this torsion moved
up the right side of the larva to the dorsal surface, and thus the left
organs become right and vice versa. In the subsequent growth of

The second movement is a lateral torsion of the visceral mass, the foot remaining a fixed point; this torsion occurs in a plane approximately at right angles to that of the first movement, and carries the pallial aperture and the anus from behind forwards. If, at this moment, the animal were placed with mouth and ventral surface turned towards the observer, this torsion carries the circumanal complex in a clockwise direction (along the right side in dextral forms) through 180° as compared with its primitive condition. The (primitively) right-hand organs of the complex thus become lefthand, and vice versa. The visceral commissure, while still surrounding the digestive tract, becomes looped; its right half, with its proper ganglion, passes to the left side over the dorsal face of the alimentary canal (whence the name supra-intestinal), while the left -half passes below towards the right side, thus originating the name infra-intestinal given to this half and to its ganglion. Next, the shell, the coil of which was at first exogastric, being also included in this rotation through 180°, exhibits an endogastric coiling (fig. 1, B, C). This, however, is not generally retained in one plane, and the A, spire projects, little by little, on the side which was originally left, but finally becomes right (in dextral forms, with a clockwise direction, B, if viewed from the side of the spire; but counter-clockwise in sinistral forms). Finally, the original symmetry of the circumanal complex vanishes; the anus leaves the centre of the pallial cavity and passes towards the right side (left side in sinistral forms); the organs of this In, side become atrophied and disappear. The essential feature of the asymmetry of Gastropoda is the atrophy or disappearance of the primitively left half of the circumanal complex (the right half in lug, sinistral forms), including the gill, the auricle, the osphradium, the hypobranchial gland and the kidney.

In dextral Gastropods the only structure found on the topographically right side of the rectum is the genital duct. But this is not part of the primitive complex. It is absent in the most primitive and symmetrical forms, such as Haliotis and Pleurotomaria. Originally the gonads opened into the kidneys. In the most primitive existing Gastropods the gonad opens into the right kidney (Patellidae, Trochidae, Fissurellidae). The gonaduct, therefore, is derived from

FIG. 3.-Sketch of a model designed so as to show the effect of torsion or rotation of the visceral hump in Streptoneurous Gastropoda.

the sub-intestinal) visceral

Wooden arc representing

the base-line of the wall

the sub-intestinal) visceral x, x', Pins fastening the elastic Primarily right (subsequently ganglion.

cord (representing the visceral nerve loop) to W

the shell the spire comes to project on the right side, which was originally the left. Neither the rotation of the shell as a whole nor its helicoid spiral coiling is the immediate cause of the torsion of the body in the individual, for the direction of the torsion is indicated in the segmentation of the ovum, in which there is a complete

reversal of the cleavage planes in sinistral as compared with dextral Order 1. ASPIDOBRANCHIA. These are the most primitive Gastroforms. The facts, however, strongly suggest that the original cause pods, retaining to a great degree the original symmetry of the of the torsion was the weight of the exogastric shell and visceral hump, which in an animal creeping on its ventral surface necessarily

fell over to one side. It is not certain that the projection of the spiread
to the originally left side of the shell has anything to do with the
falling over of the shell to that side. The facts do not support such
a suggestion. In the larva there is no projection at the time the
torsion takes place. In some forms the coiling disappears in the
adult, leaving the shell simply conical as in Patellidae, Fissurellidae,
&c., and in some cases the shell is coiled in one plane, e.g. Planorbis. Inni gain
all these cases the torsion and asymmetry of the body are unaffected.
The characteristic torsion attains its maximum effect among the
majority of the Streptoneura. It is followed in some specialized ods to im
Heteropoda and in the Euthyneura by a torsion in the opposite
direction, or detorsion, which brings the anus farther back and un-
twists the visceral commissure (see Euthyncura, below). This con-
clusion has shown that the Euthyneura do not represent an archaic
form of Gastropoda, but are themselves derived from streptoneurous
forms. The difference between the two sub-classes has been shown
to be slight; certain of the more archaic Tectibranchia (Actaeon)
and Pulmonata (Chilina) still have the visceral commissure longd om
and not untwisted. The fact that all the Euthyneura are herma-dajo pois
phrodite is not a fundamental difference; several Streptoneura are so, di sange
likewise Valvata, Oncidiopsis, Marsenina, Odostomia, Bathysciadium,
Entoconcha.

Classification.-The class Gastropoda is subdivided as follows:

Sub-class I. Streptoncura.
Order 1. Aspidobranchia.
Sub-order 1. Docoglossa.
2. Rhipidoglossa.

Order 2. Pectinibranchia.
Sub-order 1. Taenioglossa.
Tribe 1. Platypoda.
2. Heteropoda.
Sub-order 2. Stenoglossa.
Tribe 1. Rachiglossa.
2. Toxiglossa.

Sub-class II. Euthyncura.

Order 1. Opisthobranchia.
Sub-order 1. Tectibranchia.
Tribe 1. Bullomorpha.

2. Aplysiomorpha.

3. Pleurobranchomorpha.

Sub-order 2. Nudibranchia.

Tribe 1. Tritoniomorpha.

"

2. Doridomorpha.

3. Eolidomorpha.

4. Elysiomorpha.

Order 2.. Pulmonata.

Sub-order 1. Basommatophora.
2. Stylommatophora.
Tribe 1. Holognatha.

2. Agnatha.

3. Elasmognatha.

"

4. Ditremata.

Sub-Class I.-STREPTONEURA

In this division the torsion of the visceral mass and visceral commissure is at its maximum, the latter being twisted into a figure of eight. The right half of the commissure with its ganglion is supra-intestinal, the left half with its ganglion infra-intestinal. In some cases each pleural ganglion is connected with the opposite branch of the visceral commissure by anastomosis with the pallial nerve, a condition which is called dialyneury; or there may be a direct connective from the pleural ganglion to the visceral ganglion of the opposite side, which is called zygoneury. The head bears only one pair of tentacles. The radular teeth are of several different kinds in each transverse row. The heart is usually posterior to the branchia (proso-branchiate). The sexes are usually separate.

The old division into Zygobranchia and Azygobranchia must be abandoned, for the Azygobranchiate Rhipidoglossa have much greater affinity to the Zygobranchiate Haliotidae and Fissurellidae than to the Azygobranchia in general. This is shown by the labial commissure and pedal cords of the nervous system, by the opening of the gonad into the right kidney, and by other points. Further, the Pleurotomariidae have been discovered to possess two branchiae. The sub-class is now divided into two orders: the Aspidobranchia in which the branchia or ctenidium is bipectinate and attached only at its base, and the Pectinibranchia in which the ctenidium is monopectinate and attached to the mantle throughout its length.

onsin foos bo podaw albis fret o (Robin, Dall). This fact led Cuvier erroneously to the belief that a duct existed leading from the gonad to this papilla. The position of the gonad, best seen in the diagrammatic section (fig. 13), is, as in other Aspidobranchia, devoid of a special duct communicating with the exterior. This condition, probably an archaic one, distinguishes the Aspidobranchia from other Gastropoda.

The digestive tract of Patella offers some interesting features. The odontophore is powerfully developed; the radular sac is extraordinarily long, lying coiled in a space between the mass of the liver and the muscular foot. The radula has 160 rows of teeth with twelve teeth in each row. Two pairs of salivary ducts, each leading from a salivary gland, open into the buccal chamber. The oesophagus leads into a remarkable stomach, plaited like the manyplies of a sheep, and after this the intestine takes a very large number of turns embedded in the yellow liver, until at last it passes between the two renal sacs to the anal papilla. A curious ridge (spiral? valve) 1) of murdes 1340 cl o id our thoubn

anterior part of the visceral hump of Patella to show the two renal FIG. 14.-Vertical section in a plane running right and left through organs and their openings into the pericardium. (J. T. Cunningham.) Large or external or right f, Manyplies. renal organ. Narrow process of the same

8, Epithelium of the dorsal sur

Renal epithelium lining the

which secretes a slimy cord is found upon the inner wall of the intestine. The general structure of the Molluscan intestine has not been sufficiently investigated to render any comparison of this structure of Patella with that of other Mollusca possible. The eyes of the limpet deserve mention as examples of the most primitive kind of eye in the Molluscan series. They are found one on each cephalic tentacle, and are simply minute open pits or depressions of the epidermis, the epidermic cells lining them being pigmented and connected with nerves (compare fig. 14, art. CEPHALOPODA).