the opening in the bladder might be enlarged accordingly. Having satisfied myself on this head, I hooked up the fundus of the bladder with my finger, and enlarged the incision towards its cervix, sufficiently to admit of the free extraction of the stone. Some little difficulty here arose in disengaging the stone from its situation, notwithstanding the great assistance obtained by the introduction of the fore-finger of my right hand into the rectum, while the fore-finger of my left was in the bladder to cant or turn the stone, so as to extract it by its smaller axis; and, indeed, this was not effected until the single blade of a pair of small stone forceps was introduced. The stone being thus turned, it was easily removed with the finger and thumb. In point of fact, so firmly did the bladder grasp the calculus, that the idea was conveyed to our mind of its actual adhesion to the coats of that viscus.

One small cuticular artery was divided at the first incision, and secured at the time, to prevent the future steps of the operation being obscured by the bleeding, and the subsequent issue of blood into the cavity of the pelvis.

Two slips of linen, dipped in oil, were introduced through the external wound on each side of the bladder, but not into the bladder, as was done in your first ease, published in the Philosophical Transactions; a gum elastic catheter was passed into the bladder so as just to enter its cavity, and no farther, and was secured in this situation by tapes attached to the instrument, and to an elastic band, or retainer, in the manner described in your paper, but which in this case was made of flannel, lined with calico. The sides of the wound were brought together by slips of sticking plaster, and the parts supported by a flannel roller, passed three or four times round the pelvis and the lower part of the abdomen. The patient, by means of pillows, was placed on an inclined plane, a vessel was secured to the end of the catheter to receive the urine, and he had an anodyne draught administered to him.

Afterwards republished in your third vol. of Strictures.

I am fully aware that there are those who may imagine the trifling difficulty we experienced in extracting the stone, arose from the depth, narrowness, and consequently from the supposed tightness, as it were, of the wound, through the parietes of the abdomen; but I can assure them that such was not the fact, for I enjoyed the most perfect freedom in that respect. The circum-' stance in my mind arose rather from the position of the stone, its size, and the strong contraction of the bladder upon it; for it will be borne in recollection that the bladder, in this case, had never been distended beyond the size of the calculus, and that which two ounces of urine would occasion. What the bladder wanted in capacity, it possessed in the increased thickness of its parietes, for it was fully a quarter of an inch thick at the part divided; so that its muscular power must, therefore, have been considerable. I cannot avoid, in this place, repeating the great advantage to be derived from dislodging the stone, in such cases, by the introduction of the finger into the rectum, and which appears to me a great improvement in this mode of operating.

19th June. Slept two hours during the night; about six ounces of urine came through the catheter, the rest by the wound. His pulse this morning was 120, and full; he was bled, therefore, to twenty ounces, and I prescribed saline draughts every three hours, each containing ten drops of liquor antimonialis. He was otherwise free from pain, and only complained of a smarting in the wound.

20th. Had four hours continued sleep during the night, for the first time in his life: urine passed equally by the instrument and the wound: pulse about 100, and soft, and he perspired profusely during the night: the draughts were continued, and he was supplied with barley-water for his common drink. An aperient draught was prescribed for the following morning.

21st. Slept nearly six hours last night: pulse 90: skin moist: no pain whatever: his bowels were well moved by the draught: urine passed as the day before, and he sat up about two hours, with his feet hanging over the side of the bed, and resting upon a

chair.

No one bad symptom occurred afterwards: the urine continued for about five weeks to come occasionally by the wound in small quantities, the rest by the natural passage: the wound itself continued to look healthy from the first, and gradually closed until the 31st July, when it was completely healed, and the patient voided his urine in a full stream through the urethra.

Thus terminated this successful case; and, I am strongly inclined to believe, that the patient's recovery would have been still more speedy, had the catheter been sooner altogether withdrawn from the bladder; for it was retained almost constantly in that situation about three weeks, removing it night and morning only, for the purpose of clearing it of mucus.

The stone weighed eleven drachms two scruples and four grains. It is two inches long and one inch and half in width. A section has been made of it, and my friend Dr. Prout has had the kindness to analyze it for me. The result will be found in the Doctor's note addressed to me.

The nucleus of the calculus which you were kind enough to leave for me, consists essentially of the lithate of ammonia, mixed with some oxalate of lime, (and probably a little carbonate of lime,) the phosphates, and animal matter. The exterior lamina are chiefly composed of the phosphates; but two or three small fragments detached from the surface were found to consist chiefly of the phosphate of lime; and this circumstance made me anxious VOL. XX.

E

to see the urine, as I had never before known this salt deposited alone from that secretion, and hence had been led to believe that calculi composed entirely of that substance were not of urinary origin, but formed in a manner analogous to those met with in the prostate gland.

The specimens of urine which you were good enough to send me arrived in safety, but I am sorry to say that they throw no light on the subject, or rather on the point in question. They are alkaline, and of a very bad character, and abound in the mixed phosphates, (that is, the phosphate of lime and the triple phosphate of magnesia and ammonia,) as is usual in such

In the Miscellaneous Intelligence contained in your last number, you have remarked, that you should take notice of such facts respecting the theory and improvement of calcareous cements as were brought to light at different times, with the fair conclusions to be drawn from them, being convinced, in the highest degree, of the importance of the subject, and of the advantage which the investigation must lead to.

Having for nearly thirty years experienced, practically, the imperfections of the various cements in use in England, I have been led into a variety of examinations of them, and do not hesitate to communicate to you an account of a series of experiments which

will, in my opinion, contribute essentially to a knowledge of the subject.

.. The first endeavour at investigation was made by a comparison of various burnt clays, obtained in the neighbourhood of London and in Kent, with the imported Pozzolano, as sold in London; but the imported material was so variable in its nature, that little re sulted beyond a knowledge that it possessed more calcareous matter, and that it was more uncertain and variable in the sizes of the grains, than that of British manufacture.

The next endeavour was to ascertain what, practically, were the best sizes of the particles to be used with lime, and in what state and what species of lime entered best into the combination with them.

It appeared that either the foreign or British Pozzolano, if reduced into a very fine powder, lost considerably its power of adhesion, though it was more plastic. It necessarily was inferred, that the greater the variety of dimension of the particles, the greater would be the entanglement of the asperities, and, consequently, the greater the adhesion. Of the mortar made, it also appeared that the finer the lime could be ground, the more perfect would be the combination, and the harder the mortar obtained, because the hard particles of the Pozzolano being in a state of actual contact, no compression was likely to take place; and which, in fact, upon the subsequent investigations proved to be the case.

My reasons for trying the Pozzolano were these. I conceived that I should have two causes for the induration of the mortar; one, the disposition which many burnt materials have to unite intimately with lime; the other, the variety of form which the frac ture of burnt clay produces; the real difficulty which existed was, the obtaining a perfect knowledge of the best state, and the best mode of indurating properly the clay itself. For if the burning of the clay were such as to cause vitrification, an imperfect mortar was made; perfect glass, scoria, and pumice-stone, produced very inferior mortar; perfect Pozzolano appeared to be made when a chalky clay was so indurated by fire as to put on the appearance of a commencing vitrification only.