Under this treatment the symptoms produced by the muriatic acid subsided; but the appearance of the urine was not at first improved.

On the 20th, the film of triple phosphate formerly constantly observed in the urine began to decrease, but the white sand remained as abundant as before; he was therefore directed to take twenty grains of citric acid twice a day, and to continue the use of acid drink, as formerly.

The additional acid at first disagreed with the bowels; but this effect soon ceased, and the sediment was only observed in the urine voided in the morning; he therefore took another dose of the acid every night. This plan was pursued with little intermission until the beginning of December: the deposition of the phosphates gradually ceased, and he remained in perfect health until the middle of May, 1812, when after violent exercise and taking more wine than usual, the white sand again made its appearance in great abundance; his stomach became extremely irritable, and the acids, which he had before employed with success, brought on considerable irritation in the bladder. The addition of ten drops of laudanum to each dose of the citric acid prevented this effect, and he was thus enabled to continue the acid, which in a fortnight relieved his complaint.

This gentleman informed me, that whenever he omitted the use of an acid diet, or took much wine, especially port, his urine deposited the white sand and mucus, for two or three successive days.

Case 4. A gentleman, eighty years of age, who had twice submitted to the operation for the stone within five years,

voided with his urine considerable quantities of white sand and mucus.

From the age of this patient, and the account of his case, there appeared little doubt that the calculi had been formed in consequence of a diseased prostate gland, in the manner described by Sir EVERARD HOME,* and on examining them, they were found to contain no uric nucleus, nor indeed had there been any symptoms of disease in the kidneys, at any previous period.

This gentleman had been in the habit of taking soda water, from which he was now desired to abstain, with a view of putting him upon the acid plan of treatment. He was ordered to take eight drops of muriatic acid three times a day in two table-spoonsfull of water; but the third dose produced so much irritation in the bladder, and consequent increase of his symptoms, that it became necessary to adopt another treat

ment.

Lemon juice, or a solution of the pure citric acid, when given in quantity sufficient to produce any change in the appearance of the urine, had the same effect as the muriatic acid.

As water impregnated with carbonic acid could not be procured, he was directed to dissolve, in separate portions of water, twenty grains of citric acid, and thirty grains of the crystallised carbonate of potash, and to take the mixed solutions, during the effervescence. This quantity was at first only taken night and morning, but as it agreed perfectly well, it was afterwards repeated four and five times daily. Under these circumstances the appearance of the urine was soon improved, and both the mucus and the sand were considerably

* Practical Observations on the Treatment of Diseases of the Prostate Gland, p. 39.

diminished in quantity. In six weeks the urine, when voided, was transparent; but a considerable deposition of the phosphates took place, when it had remained for some hours at rest, In this state he left London, and has since informed me, that the sediment gradually diminished under the use of the carbonic acid, that his urine is never turbid, and that the irritation in the bladder has entirely subsided.

It did not appear necessary to detail the minutiae of the above cases; they have been selected with a view to elucidate the treatment of the disease, as far as it depends upon chemical principles, and to furnish the data upon which the following conclusions are founded.

1. That where alkalies fail to relieve the increased secretion of uric acid, and to prevent its forming calculi in the kidneys, or where they disagree with the stomach, magnesia is generally effectual, and that it may be persevered in for a considerable time without inconvenience, where the tendency to form excess of uric acid remains.

2. When the alkalies, or magnesia, are improperly continued, after having relieved the symptoms connected with the formation of the red sand, or uric acid, the urine acquires a tendency to deposit the white sand, consisting of the ammoniaco-magnesian phosphate and phosphate of lime.

3. The mineral acids, (muriatic, sulphuric, and nitric) diminish, or entirely prevent the deposition of the phosphates ; but are apt to induce a return of the red gravel.

4. That vegetable acids, especially the citric and tartaric, are less liable to produce the last mentioned effects, even when taken in large doses for a long time; and that carbonic acid is particularly useful in cases, where the irritable state of the bladder prevents the exhibition of other remedies.

XXVII. Additions to an Account of the Anatomy of the Squalus Maximus, contained in a former Paper; with Observations on the Structure of the Branchial Artery. By Sir Everard Home, Bart. F. R. S.

Read June 24, 1813.

My former account was taken from a Squalus Maximus caught at Hastings, in November, 1808, and the parts which I examined were brought to London by Mr. CLIFT, who went down, at my desire, to dissect them; but the weather being stormy and cold, the fish was brought no further than the beach, so that the examination was conducted under great disadvantages, and the parts brought away were in a mutilated state. The sketch of the fish made upon the spot by Mr. CLIFT is now found to be generally correct, except the omission of a small fin between the anus and tail, which had been buried by the weight of the fish in the sand.*

Two fishes of the same species have since been caught at Brighton, and one of them was brought to London in December, 1812, which I had an opportunity of examining, assisted by Mr. CLIFT. It is not my intention, on the present occasion,

* The omission of this small fin in the drawing is an error of considerable importance, as it deprived the fish of one of its characteristic marks, and has led naturalists, who have since had the opportunity of examining other specimens with more accuracy, to conclude that this fish was a distinct species from those which they described; I am therefore particularly desirous to correct the mistake.