CHAPTER II.. Herniæ.[6]

HERNIÆ.

Footnote 6:

For a fuller description of herniæ and their treatment, see Möller and Dollar’s “Regional Surgery,” pp. 263–309.

CONGENITAL HERNIÆ.

PERINEAL HERNIA OF YOUNG PIGS.

This variety is very common in young pigs, on account of their anatomical peculiarities and of the persistence and enlargement of the inguinal canal. Loops of intestine, impelled by their own weight, accumulate at the lowest point and readily pass into the canal.

It is usually when the little pig begins to eat, i.e., a fortnight or three weeks after birth, that the symptoms become plainly apparent.

The hernia is indicated by a swelling which commences in front of the pubis and extends backwards behind the hind limbs. When the herniated loop of intestine is examined by palpation, the presence of liquid in it can be detected, particularly after a meal, while a characteristic gurgling sound is heard.

=Diagnosis.= To confirm the diagnosis, the animal is placed on its back, whereupon reduction as a rule is easily effected. As soon as the animal rises again the hernia returns.

=The prognosis= is not grave.

=The treatment= is exclusively surgical, and the hernia can be reduced and castration performed at one and the same time. The animal being placed on its back and firmly held, an incision of about 2 to 3 inches in length is made in the inguinal region, dividing the skin and subcutaneous connective tissue only. The vaginal sheath is then completely isolated, the hernia reduced, and a ligature applied to the sheath and the spermatic cord close to the abdominal wall. The testicle is then removed.

If adhesions have been set up, which is quite exceptional, the vaginal sheath is incised and the loop of adherent intestine liberated, when it can readily be returned. The vaginal sheath and spermatic cord are then twisted as high as the level of the inguinal ring and tied with catgut. To prevent this ligature becoming displaced, it should be fixed by passing a sterilised thread through it and through the mass of tissue; the hernial sac should be divided immediately below. In order to ensure greater security, it may even be desirable to pass a suture through the margins of the inguinal ring.

UMBILICAL HERNIA.

Umbilical hernia is less common in young animals of the bovine, ovine and porcine species than in the foal, and when existing almost always disappears at the period of weaning. The rumen then assumes its full development, the loops of intestine are displaced and thrust towards the sublumbar region, and the hernia disappears. The same is true of the young pig, the development of the stomach producing the same favourable result.

In the rare cases where this hernia is not reduced spontaneously, it may be necessary to utilise the methods so frequently employed in the foal, and, despite the number of these, there are only two which can thoroughly be relied on to give good results.

In the first, irritants are employed.

Subcutaneous injections of concentrated solution of common salt, filtered and sterilised, or 10 per cent. solution of chloride of zinc produce enormous engorgement of the connective tissue, which thrusts back the herniated loop of intestine and later causes the development of very resistant fibrous tissue, which prevents the hernia returning.

To ensure this result, however, it is indispensable that perfect asepsis should be observed in the injections, for if germs are introduced severe suppuration occurs at the point of injection. The injections are made at four opposite spots in the subcutaneous tissue surrounding the hernia, 1 to 2 drachms of saline solution being injected at each spot; of the chloride of zinc solution half a cubic centimètre is used. This method is only of value in small herniæ, which may sometimes be cured by the application of sinapisms alone.

The second method is applicable to larger herniæ, and aims at destroying the hernial sac.

The application of clams is simplest, and can be recommended. The patient is placed on its back, reduction is effected, the hernial sac is drawn upwards vertically, and the clams placed as near the abdominal wall as possible, after care has been taken that no portion of the intestine is included in the sac. The clams are kept in place by a suture passed through the neighbouring tissues.

In other cases where a radical cure is necessary, because of adhesions within the hernial sac, the patients are similarly placed on their backs, the hernial sac is opened aseptically, the adherent parts liberated, the herniated portions of intestine reduced, and the hernial ring sutured with sterilised strong silk, the skin being afterwards brought together with silk sutures after removal of the sac itself. A surgical dressing can then be applied to the umbilicus. The patients should be carefully dieted.

When the hernial ring is large and its lips widely dilated, the silk sutures, even when supported by secondary sutures, sometimes cut through the tissues and do not achieve the desired result.

Degive’s method (see “Möller and Dollar’s Regional Surgery,” p. 304) can then be employed. The hernial sac is opened under antiseptic precautions, in order to break down any existing adhesions, and the skin and edges of the hernial ring are transfixed with packing needles about 8 inches long. Above these is adjusted a clam, which is closed, by means of a screw and firmly secured. The packing needles are then replaced with horse-shoe nails, the points of which are bent round. In about a week the necrotic tissue falls away, and recovery occurs even in severe cases in which previous treatment had failed.

ACQUIRED HERNIÆ.

Acquired or accidental herniæ are not serious, and only deserve to be studied in so far as they affect organs contained within the abdominal cavity. They may result from violence, or may occur without the intervention of any external cause.

Traumatic herniæ may occur at any point in the abdominal wall. Under the influence of a violent blow from a waggon pole, a horn thrust, a kick, a fall, etc., the muscular tunic of the abdominal wall is injured and becomes fissured in the direction of its fibres. The peritoneum is rarely affected. Being pushed outwards by the digestive viscera, however, the peritoneum projects into the muscular layer, distends it, separates the layers of subcutaneous tissue, and finally forms a distinct hernia.

The consequent disturbances are more or less marked and the lesions more or less variable, according to the part affected. In the lower region fissure of the abdominal wall affects the rectus abdominis, obliquus abdominis and transversus abdominis, and on the right side gives rise to hernia of the abomasum or small intestine, on the left of the rumen. In the lateral regions muscular fissures can be produced only in the transversus and obliquus abdominis muscles. Hernia of the rumen is rare on the left side. On the right side hernia of the intestine is more readily produced.

In all cases where hernia is suspected, the hernial orifice should be examined. Its situation will at once show which organ is affected.

Spontaneous herniæ are very rare in the domesticated animals. They occur only in aged animals, and various reasons have been suggested to explain their appearance. Certain herniæ of this character are only found in old female animals which have borne a considerable number of young. Repeated gestation produces elongation and relaxation of the muscular fibres from the weight of the fœtus and its envelopes. In time, the abdominal walls become thinner and thinner under the weight of the viscera, and thus facilitate the slow formation of a hernia. Certain practitioners consider that some of these spontaneous herniæ are due solely to the pressure produced by the distended viscera, as for example in greedy-feeding animals. In such cases the weight of the viscera would cause, as in the previous case, a certain degree of anæmia and emaciation of the abdominal muscles.

These spontaneous ventral herniæ are due in reality to changes in the nutrition of the abdominal wall, the exact cause of which it is difficult to ascertain. The elastic tunic becomes atrophied, and ceases to act as an automatic girth; the muscular wall gradually becomes sclerosed from the white line towards the sides, and having lost its elasticity becomes distended and thinned.

These changes are not exclusively caused by old age, for they may be found even in young animals.

Nothing can be done in cases of spontaneous herniæ. The qualities originally pertaining to the abdominal wall cannot be restored, and =treatment= is confined to applying suspensory bandages, and, where possible, preparing the animals for slaughter.

HERNIA OF THE RUMEN.

=Causation.= Hernia of the rumen is, as a rule, of traumatic origin, and always occurs in the left flank, either in the lower or middle regions. Cases of spontaneous hernia of the rumen have been observed in very old and anæmic animals, as well as in females which have borne many young and which have suffered from spontaneous progressive hernia of the uterus.

=Symptoms.= The symptoms are the same in all herniæ. Immediately after the injury the abdominal organs show a tendency to escape in the direction of least resistance. A fold of the rumen passes through the muscular fissure, and a swelling soon becomes visible externally, which alters the contour of the abdomen. Most frequently at this time traces of the injury can be detected on the surface of the skin, either the linear trace due to a horn thrust, the ill-defined lesion due to a kick, or what not. There follows rapid swelling, which results from the inflammatory reaction due to rupture of small vessels within the muscle. A certain amount of sanguineous exudation and of œdematous swelling occurs, and may at first suggest the existence of an abscess of the abdominal wall. At the same time there is more or less fever, which may continue for a few days, but the swelling seldom lasts very long; in two or three days even, it becomes reabsorbed, commencing at the upper part and diminishing progressively downwards.

Henceforth the hernia alone remains.

It is soft, compressible, and sometimes susceptible of reduction. On palpation, the operator feels a rupture extending through the tunic and the abdominal wall, sometimes even through the muscular tissue of the rumen, in cases where the skin is neither perforated nor torn through. The mucous membrane of the rumen is rarely ruptured.

Whether or not the peritoneum is injured, the rumen presses between the lips of the wound, thrusts back the skin, and separates the connective tissue, thus setting up local irritation and œdematous swelling. The rumen may contract more or less close adhesions with the abdominal wall, and even with the subcutaneous tissues.

Afterwards, when the exudate has been reabsorbed, palpation reveals a different condition of things. The mass is uniformly fluctuating or semi-fluctuating, and is surrounded at the base by an indurated ring of very varying dimensions. The final indication—which, however, is not invariably seen—deserves attention, viz., the change in volume of the hernia at different moments, particularly during meals. This change in size only occurs if the hernial orifice is large.

In cases of spontaneous hernia of the rumen, the condition is not fully established at first. It is always progressive, and the lesion is situated in the lower abdominal region. It increases in size from day to day, from week to week, whilst the animals lose appetite and flesh. Spontaneous herniæ are never accompanied either by exudation, engorgement, fever, or traces of mechanical injury.

When only slightly developed, herniæ do not threaten life, a fact which often prevents the owners troubling about them. Progressive herniæ may become of considerable size, and two cases are recorded in one of which the opening of the hernial sac was 13½ inches in length and 18 inches in width, and in the other 28 inches in length and 24 inches in width. The latter is the largest ever recorded.

=Complications.= Complications are not always grave. If the hernia is little marked the function of the rumen is not greatly affected and its rhythmic contraction continues. When the original injury has caused rupture of the muscular tissue of the rumen, and the mucous membrane has passed into the opening, it may become strangulated and gangrenous.

Finally, if the mucous membrane has been torn at the same time as the muscular tissue (which is very uncommon), alimentary material may escape into the subcutaneous connective tissue, setting up either cellulitis and death by infection, or suppuration; abscess formation and rupture towards the exterior, followed by a persistent sinus; or again septic peritonitis, and death.

The same results may occur when the hernia is in a very low portion of the abdomen; food accumulates in it, becomes stagnant there, sets up local irritation and inflammation, and sometimes abscess formation with external discharge, followed by fistula of the rumen.

Gastric fistula without secondary complications is compatible with life, and even with fattening for slaughter, provided the peritoneum covering the rumen becomes attached to the opposing surface of peritoneum around the perforation. The fistula is then surrounded by a circular mass of fibrous tissue, forming a kind of sleeve.

=Lesions.= The lesions are the same in all herniæ. They consist primarily in rupture of the abdominal wall, and, later, of sero-sanguinolent infiltration of the margins of the wound, similar to that accompanying the formation of an abscess. Hernial swellings are of very varying size. Apart from cases similar to those above described, the swelling may be simply an inch or two in diameter, or it may attain the dimensions of a hen’s egg or even of a man’s fist.

When the abdominal tunic only has been ruptured, as is most frequently the case, the peritoneum is thrust outwards and forms a cavity, the hernial sac. This sac is absent when the peritoneum is ruptured. Little by little the surrounding connective tissue forms a pseudo-serous hernial sac. But, nevertheless, in some cases there may be found, immediately under the skin, the mucous membrane of the rumen in a state of congestion and ready to become gangrenous.

=Diagnosis.= Easy in all cases.

=Prognosis.= Very variable. In the case of small herniæ situated in the lateral regions of the abdomen the prognosis is not very grave. If, however, the rupture is wide, and situated in the lower portion of the abdominal walls in a dependant position, the hernial swelling steadily grows in size in consequence of the weight of the food which is constantly thrust in this direction by the contraction of the rest of the rumen, and recovery is impossible. The only resource is to fatten the animals as quickly as possible for slaughter.

HERNIA OF THE ABOMASUM.

=Causation.= This condition is due to causes similar to those above mentioned, including mechanical violence. It is rare in adults, but much commoner in young animals, especially in sucking calves, where the abomasum is the most highly developed digestive compartment.

Hernia of the abomasum is produced essentially and almost exclusively by horn thrusts inflicted when calves attempt to suck cows other than their own mothers.

=Symptoms.= Hernia of the abomasum always occupies a certain position in the lower part of the right flank, or, rather, in the space comprised between the white line and the lower part of the circle of the hypochondrium.

The immediate symptoms are similar to those of hernia of the rumen. They include: progressive swelling, formation of a peripheral œdematous ring, interstitial sero-sanguineous exudation, which becomes absorbed after a few days; finally, the development of a hernia, formed as a rule by the larger curvature of the viscus, which is in direct contact with the abdominal wall.

=The lesions= are those common to all hernia, and usually include a partially healed wound.

=Diagnosis.= The diagnosis is easy, particularly in calves, and the possible existence of the condition should always be borne in mind when dealing with injuries of the right pre-umbilical zone. An abscess of the lower abdominal wall may occur at or near the umbilicus as a result of omphalitis or umbilical phlebitis, but it is readily distinguished from a hernia.

=The prognosis= is graver than in the case of hernia of the rumen, for the displacement of the abomasum interferes with its regular function. The prognosis varies, however, in accordance with the size of the hernia. If the rupture is small, there is some chance that the abomasum, on account of its longitudinal position, many penetrate but slightly into the fissure.

If, on the other hand, the rupture is large, the prognosis becomes very serious. It is sometimes best to slaughter the animal, if in good condition; otherwise an operation is necessary.

HERNIA OF THE INTESTINE.

=Causation.= This is due to the same cause as hernia of the rumen—a blow which, while injuring the skin only to a trifling extent, damages the abdominal walls, and even the intestine itself.

=Symptoms.= The hernia is situated in the lower or lateral zone of the right flank.

The symptoms present some peculiarities. The loop of intestine which has passed through the aperture in the abdominal walls becomes distended by the accumulation in it of semi-liquid alimentary material, and, acting by its own weight, produces a hernial sac, which steadily grows in size. The skin being very mobile, and the subcutaneous connective tissue very loose, they readily yield and become separated. The inflammatory symptoms disappear, and are followed by a swelling under the skin, which is compressible all over, and can readily be reduced, whereupon it gives forth a gurgling noise, or a sound as of borborygmus. Reduction is easier when the animal is lying on its left side, or on its back.

=Complications.= Strangulation of the small intestine is the only serious complication in this form of hernia, but it is very dangerous. It occurs frequently when the rupture is somewhat highly-placed on the lateral portion of the abdominal wall, because the loops of intestine have a tendency to descend, thrusting away the skin owing to the weight of material which they contain.

The partially digested food is apt to accumulate in the herniated loop, and hernial engorgement, the first phase of strangulated hernia, rapidly occurs.

Fermentation is set up in the half-digested food, and putrid gases are generated. Thus the hernial sac becomes distended, the vessels are compressed, circulation is arrested, and gangrene supervenes.

At this time gurgling sounds and a certain degree of tympanitic resonance may be noted. These are followed by all the symptoms of intestinal strangulation—namely, intense colic, which suddenly disappears when the intestine becomes mortified, absolute loss of appetite, stoppage of rumination, constipation, suppression of defæcation, tympanites, and peritonitis.

=The diagnosis= is comparatively easy at an early stage, owing to the peculiar character of the soft swelling, which is easily compressible. At first there may be difficulty in distinguishing it from a collection of serous fluid, but the facility with which the swelling can be reduced removes any doubt.

=The prognosis= is always serious, on account of possible complications, due to strangulation of the herniated loop. When the hernia is chronic, reduction is much more difficult, there being, as a rule, adhesions between the intestine and the hernial sac.

TREATMENT OF HERNIÆ.

Numerous attempts have been made to treat abdominal hernia in bovine animals.

Irritant and vesicant applications to the skin have been recommended, with the object of producing a large swelling, and thus thrusting back the herniated mass into its proper position.

One of the most popular of these applications is nitric acid of a strength of 36° Baumé, applied to the skin twice at an interval of ten days. Skilfully used, it gives good results in umbilical herniæ, but its effects in ventral herniæ are less certain. It causes slow mortification of the skin, abundant subcutaneous swelling, and produces an eschar, which separates in about a fortnight.

An ointment of yellow chromate of potash (1 to 8) has been recommended, and can be applied two or three times at intervals of eight or ten days.

Bandaging and various forms of local dressing have also been employed from time to time. Serres employed simple bandages similar to those used in cases of inguinal or crural hernia in human beings. These bandages have a pad, which is applied over the hernial opening, but their action is strictly palliative. They simply allow of the animal being kept a certain length of time for fattening.

When the hernia has been reduced recourse may be had to bandages saturated in melted pitch, care being taken to extend the dressing a considerable distance beyond the limits of the hernial opening. Successive layers of bandage are superposed across and across, and, to make the dressing more solid, the pads may be reinforced with a sheet of solid cardboard. This method only succeeds when the swelling is slight and is situated elsewhere than in the lowest portions of the abdomen.

Some practitioners prefer a cloth bandage after reduction. The bandage is ten to fifteen yards in length, and should be considerably wider than the greatest measurement of the hernial opening. Such bandages can easily be applied to calves, whose bodies are of regular shape, but in adults, in which the body is of ovoid formation, they prove faulty, and tend to slide backwards or forwards.

All these measures are merely more or less palliative and of temporary effect.

The only rational and radical treatment is surgical. This is clearly indicated when the hernia is recent and of small size. At a later stage, when fibrous adhesions have formed between the various organs, and reduction has become difficult, caution must be observed. Surgical treatment is always a serious matter, and should only be attempted in the case of valuable breeding animals, or those which cannot be sold for slaughter.

Young animals are kept without food for twenty-four hours and are cast on the side opposite the hernia; they can be placed on the right or left side, or on the back, as seems most convenient. The site of operation is disinfected, and the operation carried out with aseptic precautions. The skin covering the swelling is incised and, the margins of the hernial orifice having been examined, the sac is isolated. Next, an incision is carefully made, any adhesions which may exist are broken down and the herniated parts are reduced. It only remains to suture the wound with silk or catgut, bringing the lips of the fissure together. Finally the skin wound is firmly united, and a large suspensory bandage tightly applied.

If the hernia is of long standing, and is irreducible on account of numerous adhesions, operation may still be attempted. In that case the incision must be an inch or two longer, all adhesions should be destroyed, and the margins of the orifice need to be freshened so as to insure their uniting.

During the days following operation, the animals should have light food, principally gruel, mashes and cooked roots. But it must be borne in mind that this operation is serious, and may possibly be followed by eventration.

DIAPHRAGMATIC HERNIA.

The term diaphragmatic or mediastinal hernia denotes a condition in which certain of the abdominal viscera penetrate into the thoracic cavity. This displacement may be congenital, acquired, or accidental.

The accidental herniæ are of traumatic origin, and are often caused by fractured ribs, which injure the diaphragm. The hernia is then purely diaphragmatic.

Congenital or acquired herniæ are more frequently mediastinal; they occur exactly in the median plane as a consequence of fissure of the diaphragm above the ensiform cartilage, and cause a separation between the two layers of serous membrane enclosing the posterior mediastinum.

The region immediately behind the diaphragm in the ox being occupied by the large viscera—namely, the anterior conical portions of the rumen, the reticulum, the omasum, and the liver—diaphragmatic or mediastinal hernia is far from being common, though occasionally it may be discovered or at least suspected.

=Causation.= The causes of diaphragmatic and mediastinal hernia are closely connected with injuries in the region of the hypochondrium; with arrest in the development of the diaphragm; or with accidental vertical fissuring consequent on gestation or acute tympanites.

The fissure seems most commonly to occur between the point where the œsophagus passes through the diaphragm and the ensiform cartilage of the sternum, in which case mediastinal herniæ most commonly supervene. As, on the other hand, the rumen, owing to its size, form and position, cannot readily be displaced, the reticulum and omasum are the viscera which most commonly pass into the thorax.

=Symptoms.= In true accidental diaphragmatic hernia visceral displacement only occurs on the right side, and symptoms of this are immediately apparent. The passage of the liver, reticulum, or omasum into the right pleural sac compresses the lung, causes attacks of dyspnœa and acceleration of the heart’s action.

Percussion may not reveal any important change, but on auscultation digestive sounds can plainly be heard within the chest.

The symptoms are far from being well defined. They may be more or less intense, and colic may or may not be present. Mediastinal hernia (Fig. 223) appears to develop slowly, and it is only by degrees that the viscera become displaced.

There is then no sudden change, no clearly marked disturbance, but simply a certain amount of digestive irregularity, together with loss of appetite, cessation of rumination, slight indigestion, and moderate tympanites. The disturbance is really due to obstruction in the alimentary canal and displacement of the reticulum and omasum, so that rumination and deglutition are affected.

Very often this condition may last for weeks, in either a stationary or more or less aggravated form, so that there is an appearance of chronic gastro-enteritis, motor dyspepsia, or chronic indigestion.

Though a diagnosis in this sense would be correct, the atony of the rumen is not primary, but of mechanical origin.

One indication is constantly present, which might suggest indigestion due to overloading of the rumen, and which is also seen in ulcerative gastritis, viz., progressive stasis of food in the cavity of the rumen. When the patients remain for some time under observation, this stasis becomes every day more marked, and, being recognised, the diagnosis becomes easier. Animals suffering from mediastinal hernia lose condition, waste away, and in the end may die in a state of cachexia.

=Lesions.= The lesions vary greatly. In accidental diaphragmatic hernia they are confined to rupture of the diaphragm, sometimes of the liver, and to changes in the reticulum or omasum.

In intra-mediastinal hernia the layers of the mediastinum form a true hernial sac, and if the lesion is of old standing the displaced viscera may become attached to it, compressed, and partially strangulated.

=Diagnosis.= The diagnosis is very difficult, at all events in mediastinal hernia, and can only be arrived at by a process of exclusion. The most significant symptom is progressive stasis of food within the rumen, suggestive of some obstacle in the alimentary canal.

=Prognosis.= The prognosis is extremely grave, because it is impossible to reduce the hernia.

=Treatment.= No treatment is possible. The essential point is to confirm the diagnosis as soon as possible and to slaughter the animal while it is yet in good condition.

EVENTRATION.

Eventration belongs to the same group of lesions as herniæ, of which it is merely a more serious form. It differs from them only in the fact that the entire abdominal wall is injured. The skin, muscle, and peritoneum are torn, and the digestive organs pass into direct communication with the external air.

The name eventration has also been given to enormous subcutaneous abdominal herniæ, in which the sero-muscular wall is injured over a large area and the viscera become displaced and separate the subcutaneous tissue layers while at the same time they alter the whole shape of the abdomen.

=Causation.= The cause is always the same—some grave mechanical injury to the abdominal wall, producing an extensive perforation. The injury may be due to a horn thrust or to the animal falling on some sharp-edged body.

=The symptoms= are very marked. Through the wound, the rumen, the abomasum, or the intestine protrudes more or less. Generally it is the small intestine which becomes displaced, because it is the most mobile of the abdominal viscera. These organs soon become dried by contact with the air, and may become infected, soiled, congested, thickened, torn, or gangrenous. The successive development of these changes causes serious and violent colic, accompanied by expulsive efforts; the animals throw themselves on the ground, and may tear the mesentery, the intestines, etc. At an advanced stage the animal may stand motionless, looking at its viscera. Death may also be caused in a very short time by the intense pain.

=Diagnosis= and =Prognosis=. The diagnosis is evident. The prognosis is always very grave, although, of course, it depends on the condition of the displaced viscera.

=Treatment.= It is often useless to attempt anything, and if the animal is in suitable condition it is best, as a rule, to slaughter it.

If the accident is quite recent, and the viscera only slightly injured, surgical treatment may be attempted. With this object, the displaced organs are carefully and thoroughly washed with lukewarm boiled water, or with some unirritating disinfectant, to guard against peritonitis, and are then reduced.

The abdominal wound must afterwards be carefully sutured. This is performed in two stages. The musculo-serous layer is first brought together with catgut, or better still with silk, and the skin joined by means of deep and closely placed stitches. To prevent these sutures being torn out, and to support them, the abdomen is swathed in a broad cloth bandage, tightly applied.

FISTULÆ OF THE DIGESTIVE APPARATUS.

Fistulæ of the digestive apparatus are of accidental origin and of relatively small practical interest. In most cases they necessitate surgical and other treatment of too delicate a kind and too prolonged a character to justify the necessary expense. Their nature and origin sufficiently suggest the course to be adopted.

These fistulæ are divisible into two varieties, gastric fistulæ and intestinal fistulæ. Gastric fistulæ comprise fistulæ of the rumen, reticulum, and abomasum. They may be of external origin, but in the majority of cases they are produced by foreign objects accidentally swallowed and eliminated through the medium of an abscess of the abdominal walls. Their position and direction indicate their point of origin. (Fistulæ of the rumen appear on the left side of the reticulum, near the ensiform cartilage and middle line; those of the abomasum on the right side, near the middle line.) In doubtful cases, chemical analysis of the liquid which escapes will afford valuable information. Acidity alone is a sufficient indication in fistula of the abomasum.

Fistulæ of the rumen and reticulum are difficult to close on account of their low position in the abdominal wall, but, if great care is exercised, they may be successfully treated. Those of the abomasum, on the contrary, only tend to increase in size, and any surgical interference still further favours the destructive action of the gastric juice. As a rule, therefore, they cannot be treated.

Fistulæ of the second variety comprise all intestinal fistulæ. They may be either accidental or artificial, and they are less grave than gastric fistulæ, because they are rarely situated in the lower portions of the abdomen. With time they may become closed either spontaneously or by means of simple treatment tending to regulate the passage of food through the bowel.