at the external orifice of a fistula formed in either way, it may pass through a small opening in the coats of the rectum into the bowel. The case is then called a complete fistula. When there is no internal opening, the complaint is named blind external fistula. The external orifice is usually but a short distance from the anus, its situation being often indicated by a button-like growth; and it is in the centre of this red projecting granulation that the opening is found. The aperture, however, is not always so marked, and being very small, a mere slit concealed in the folds of the anus, cannot be detected without careful search. The course taken by a fistula varies a good deal. I have a preparation in which the opening is so close to the margin of the anus that the sinus traverses the substance of the external sphincter,-a course which is not, indeed, very uncommon. The abscess, before breaking or being opened, may, however, have burrowed to some distance, and the external orifice may be placed two or three inches off in the direction of the buttock or perineum.

Fistula in ano arises in different ways. It commonly commences in the areolar tissue, near the anus as a common phlegmonous abscess; the frequent action of the sphincter muscle, and the disturbance of the part in defecation, afterwards preventing the closure of the sac in the usual mode. This does not, however, always happen. Some years ago, I was asked to examine a robust, middle-aged professional friend, who was troubled with an abscess which had recently burst near the anus. I introduced a probe, and found by the finger in the rectum that it passed close to the mucous membrane of the bowel. I stated that he would require the operation for fistula, but requested him to remain quiet,

and wait a week. On my next visit I found the abscess closed, and the part quite sound. Most practitioners have met with similar cases. A sinus formed in this way burrows close to the outer surface of the mucous membrane of the rectum, which forms a thin barrier between the bowel and the sinus. This shortly ulcerates, and thus is formed the internal orifice of the fistula. But this does not invariably take place. I have, in a few instances, met with a fistulous opening near the anus in which no communication with the bowel could be found on the most careful examination. That such a fistula occasionally occurs I have no doubt, notwithstanding the opinion of so high an authority as Sir B. Brodie, who, in a valuable lecture on this subject, states that he is satisfied that the inner opening always exists. I have observed one fistula of the kind in the dead body; and a few preparations showing the same fact may be seen in our hospital museums'. The abscess may make its way into the bowel before bursting externally, but the inner opening is commonly formed subsequently to the outer, and is small in size. When a fistula originates, as I believe it most commonly does, in the way above described, there is a sensation of weight about the anus, swelling of the integuments, considerable tenderness on pressure, pain in defecation, and constitutional disturbance, with rigors. These symptoms are relieved after the matter is discharged. The congestions to which the hæmorrhoidal veins are very liable, I have no doubt is the principal cause of the abscesses in the vicinity of the anus, inflammation and its consequences being readily

"The Lancet, 1843-4, vol. i. p. 592.

1 Vide preparations numbered 35 and 46, series xvi. in the Collection at St. Bartholomew's Hospital.

produced in parts so favourably formed for such disease.

A sore formed in the little pouch, just within the external sphincter, and originating in the irritation to which this part is liable, instead of spreading superficially, sometimes perforates the bowel, and allows the escape of a little fæculent matter into the areolar tissue around it. I attended with Dr. Ashwell a young married lady, who had an affection of the rectum. On examination with the speculum, we detected an ulcer of the mucous membrane at the lower and back part of the rectum. A fortnight afterwards an abscess pointed near the anus, and ended in a complete fistula, which opened internally at the seat of the ulcer. A very similar case is related by Sir B. Brodie. Two years ago I operated for fistula on a patient of Mr. Arthur, of Shadwell, a married woman, who had suffered from the complaint more than usual. The wound healed in a fortnight; and on examining the part carefully, in consequence of her still suffering considerable pain, especially after defecation, I detected an ulcer at the back of the rectum, a short distance only from the inner opening of the fistula. Mr. Arthur attempted to cure this by different applications, but without success; and at the end of a month I divided the ulcer and sphincter muscle, after which the sore healed. In this case it appears that two separate ulcers formed in the rectum. One perforated the bowel; the other remained a painful superficial

Again: ulceration induced by an internal pile, and more rarely by a pointed foreign body, as a fishbone sticking in the mucous membrane, may produce perforation, and a rectal abscess. I recently operated on a fistula originating in the impaction of a fish-bone,

which had produced very extensive suppuration in the buttock and perineum. In all these cases the inner opening is found just within the external sphincter; indeed, in whatever way a fistula originates this is the most usual situation for the orifice. This point was established some years ago by M. Ribes', who examined a large number of bodies in order to ascertain the precise situation of the inner opening. In seventy-five subjects he never found the opening seated higher in the rectum than five or six lines: in a certain number it was only three or four lines up. M. Ribes' observations clearly show that the inner opening of the fistula is, in a large majority of cases, a very short distance only from the margin of the anus, and are fully confirmed by Sir B. Brodie, who, indeed, goes so far as to say," the inner orifice is, I believe, always situated immediately above the sphincter muscle, just the part where the fæces are liable to be stopped, and where an ulcer is most likely to extend through both the tunics." This, however, I have by no means found to be so constantly the case. I have examined several patients with fistula, and inspected the parts in others after death, in which the opening into the bowels was more than an inch above the external sphincter. There are several preparations of the kind in the London Museums.

Fistula occurs in phthisical subjects, originating in ulceration of the mucous membrane, and perforation of the bowel. In these cases the inner orifice is usually large in size, and there is sometimes a second opening. It is somewhat remarkable that Andral and Louis

2

Quarterly Journal of Foreign Medicine and Surgery, vol. ii.

1820.

should have found this complaint very rarely indeed in phthisis, when all surgeons in this country agree that fistula is by no means of unfrequent occurrence in patients afflicted with tubercular disease of the lungs. The abscesses originating in ulceration of the mucous membrane often form insidiously, patients suffering but little constitutional disturbance, and scarcely any local uneasiness, until the abscess is near the surface, and about to burst. In other instances the symptoms are severe there are rigors, and considerable febrile derangement, sometimes of the low type, attending the formation of fetid abscesses.

Though the inner orifice is very commonly found just within the external sphincter, communicating with one of the little sacs situated at this part, the fistula itself often extends some distance up the side of the rectum, as much as two or three inches, or even higher; and it may burrow in different directions. Formerly, surgeons, in examining patients, not being able, on passing the probe up these sinuses, to find any opening into the rectum, used erroneously to conclude that there was no communication with the bowel,-that the fistula was a blind one: but since the anatomy of the disease has been better understood, and greater pains have been taken in the examinations, search being made in the right direction, an inner opening has generally been detected. When the sinuses are tortuous or pass in different directions, there is sometimes more than one inner opening. There may be one in the usual situation, and another higher up, or on both sides of the rectum, with an indirect communication between the sinuses. Sometimes there is an external orifice on each side of the anus leading to fistulous passages, which pass to the back of the rectum, and communi

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