Though the proximate cause of the formation of the calculous concretions of the kidneys, and of chalk-stones in the gout, and of the insoluble concretions of coagulable lymph, which are found on membranes, which have been inflamed in peripneumony, or rheumatism, consists in the too great action of the absorbent vessels of those parts; yet the remote cause in these cases is probably owing to the inflammation of the membranes; which at that time are believed to secrete a material more liable to coagulate or concrete, than they would otherwise produce by increased action alone without the production of new vessels, which constitutes inflammation. As defined in Class [II. 1. 2].

The fluids secreted from the mucous membranes of animals are of various kinds and consistencies. Hair, silk, scales, horns, fingernails, are owing to natural processes. Gall-stones, stones found in the intestines of horses, scurf of the skin in leprosy, stones of the kidnies and bladder, the callus from the inflamed periosteum, which unites broken bones, the calcareous cement, which repairs the injured shells of snails, the calcareous crust on the eggs of birds, the annually renewed shells of crabs, are all instances of productions from mucous membranes, afterwards indurated by absorption of their thinner parts.

All these concretions contain phosphoric acid, mucus, and calcareous earth in different proportions; and are probably so far analogous in respect to their component parts as well as their mode of formation. Some calcareous earth has been discovered after putrefaction in the coagulable lymph of animals. Fordyce's Elements of Practice. A little calcareous earth was detected by Scheel or Bergman in the calculus of the bladder with much phosphoric acid, and a great quantity of phosphoric acid is shewn to exist in oyster-shells by their becoming luminous on exposing them a while to the sun's light after calcination; as in the experiments of Wilson. Botanic Garden, P. 1. Canto 1. l. 182, note. The exchange of which phosphoric acid for carbonic acid, or fixed air, converts shells into limestone, producing mountains of marble, or calcareous strata.

Now as the hard lumps of calcareous matter, termed crabs' eyes, which are found in the stomachs of those animals previous to the annual renewal of their shells, are redissolved, probably by their gastric acid, and again deposited for that purpose; may it not be concluded, that the stone of the bladder might be dissolved by the gastric juice of fish of prey, as of crabs, or pike; or of voracious young birds, as young rooks or hawks, or even of calves? Could not these experiments be tried by collecting the gastric juice by putting bits of sponge down the throats of young crows, and retracting them by a string in the manner of Spallanzani? or putting pieces of calculus down the throat of a living crow, or pike, and observing if they become digested? and lastly could not gastric juice, if it should appear to be a solvent, be injected and born in the bladder without injury by means of catheters of elastic resin, or caoutchouc?

M. M. Diluents. Cool dress. Frequent change of posture. Frequent horizontal rest in the day. Bathe the loins every morning with a sponge and cold water. Aerated alcaline water internally. Abstinence from all fermented or spirituous liquors. Whatever increases perspiration injures these patients, as it dissipates the aqueous particles, which ought to dilute the urine. When the constitution begins to produce gravel, it may I believe be certainly prevented by a total abstinence from fermented or spirituous liquors; by drinking much aqueous fluids; as toast and water, tea, milk and water, lemonade; and lastly by thin clothing, and sleeping on a hardish bed, that the patient may not lie too long on one side. See Class [IV. 2. 2. 2]. There is reason to believe, that the daily use of opium contributes to produce gravel in the kidnies by increasing absorption, when they are inflamed; in the same manner as is done by fermented or spirituous liquor. See Class [I. 3. 2. 11].

When the kidnies are so obstructed with gravel, that no urine passes into the bladder; which is known by the external appearance of the lower part of the abdomen, which, when the bladder is full, seems as if contracted by a cord between the navel and the bladder; and by the tension on the region of the bladder distinguishable by the touch; or by the introduction of the catheter; the following methods of cure are frequently successful. Venesection to six or eight ounces, ten grains of calomel, and an infusion of senna with salts and oil, every three hours, till stools are procured. Then an emetic. After the patient has been thus evacuated, a blister on the loins should be used; and from ten to twenty electric shocks should be passed through the kidnies, as large as can be easily borne, once or twice a day. Along with this method the warm bath should be used for an hour once or twice a day. After repeated evacuations a clyster, consisting of two drams of turpentine dissolved by yolk of egg, and sixty drops of tincture of opium, should be used at night, and repeated, with cathartic medicines interposed, every night, or alternate nights. Aerated solution of alcali should be taken internally, and balsam of copaiva, three or four times a day. Some of these patients recover after having made no water for nine or ten days.

If a stone sticks in the ureter with incessant vomiting, ten grains of calomel must be given in small pills as above; and some hours afterwards infusion of senna and salts and oil, if it can be made to stay on the stomach. And after the purge has operated four or five times, an opiate is to be given, if the pain continues, consisting of two grains of opium. If this does not succeed, ten or twenty electric shocks through the kidney should be tried, and the purgative repeated, and afterwards the opiate. The patient should be frequently put into the warm bath for an hour at a time. Eighty or an hundred drops of laudanum given in a glyster, with two drams of turpentine, is to be preferred to the two grains given by the stomach as above, when the pain and vomiting are very urgent.

[10]. Calculus vesicæ. Stone of the bladder. The nucleus, or kernel, of these concretions is always formed in the kidney, as above described; and passing down the ureter into the bladder, is there perpetually increased by the mucus and salts secreted from the arterial system, or by the mucus of the bladder, disposed in concentric strata. The stones found in the bowels of horses are also formed on a nucleus, and consist of concentric spheres; as appears in sawing them through the middle. But as these are formed by the indurated mucus of the intestines alone without the urinary salts, it is probable a difference would be found on their analysis.

As the stones of the bladder are of various degrees of hardness, and probably differ from each other in the proportions at least of their component parts; when a patient, who labours under this afflicting disease, voids any small bits of gravel; these should be kept in warm solutions of caustic alcali, or of mild alcali well aerated; and if they dissolve in these solutions, it would afford greater hopes, that that which remains in the bladder, might be affected by these medicines taken by the stomach, or injected into the bladder.

To prevent the increase of a stone in the bladder much diluent drink should be taken; as half a pint of water warmed to about eighty degrees, three or four times a day: which will not only prevent the growth of it, by preventing any microcosmic salts from being precipitated from the urine, and by keeping the mucus suspended in it; but will also diminish the stone already formed, by softening, and washing away its surface. To this must be added cool dress, and cool bed-clothes, as directed above in the calculus renis.