Dr. Withering states, that his rude conceptions were thus for the first time committed to writing, in compliance with the wishes of Dr. F. and his friends. After detailing the various practices which for a time prevailed, but afterwards successively fell into disrepute, and alluding to the general idea that stones in the bladder are principally composed of calcareous earth, fixed air, and some animal gluten, the Doctor proceeds:

After Dr. Hales had found that urinary calculi contained very large quantities of fixed air and observed that bodies deprived of fixed air, were likewise deprived of cohesive power, it was suggested that substances greedily imbibing this cementing principle would probably dissolve stones in the bladder, or rather occasion them to fall to pieces; accordingly, soap-lees, lime-water, and caustic vegetable alkali, were largely prescribed. Some seemingly happy trials at first gave wings to hopeful imagination, and it required a series of years to convince mankind that a cure for the stone was yet wanting. At length when Mr. Lane discovered that calcareous earth supersaturated with fixed air became soluble in water, and that the earthy matter in some springs was thus suspended, a flattering scene opened upon the minds of medical practitioners. They reasoned thus: stones in the bladder are principally composed of calcareous earth, fixed air, and some animal gluten; we have in vain attempted, by caustic alkalies, &c. to dissolve them by taking away their fixed air; for these caustic substances become saturated with fixed air long before they can be supposed to reach the bladder; but now, by adding more fixed air, as in the case of chalk or lime-stone, we can render them soluble, and fixed air may be taken into the stomach in great quantity without nauseous or detrimental effects. Dr. Percival occasioned a young man to drink largely of fixed air water, and found that his urine was impregnated with fixed air; so that it was judged capable of mixing with the circulating fluids, and passing the secretions without being changed. Dr. Saunders published the case of a man in Guy’s Hospital who laboured under excruciating torments from a stone in his bladder; but, in consequence of drinking largely of fixed air water and swallowing effervescing mixtures, he lost his pains, and the stone seemed to come away in fragments. Dr. Falconer made some experiments to show that pieces of calculi in a glass vessel were in part dissolved in water impregnated with fixed air. In this narration I quote only from memory, and therefore must beg indulgence for any unintentional errors.

Upon the authority of these gentlemen, with whom I am well acquainted, and of whose zeal and veracity I could not doubt, I began to put their plan in practice; but, under experience of its efficacy, I sought how to render it still more efficacious, and contrived to inject the fixed air itself into the bladder. This was accomplished without any great difficulty or pain, and the patients were readily persuaded to give it a trial, drinking, at the same time, fixed air water effervescing. Some found no relief, others thought themselves almost cured; but the event was in no case decidedly favourable, and they gradually dropped the method of cure. In time, they all became as ill as ever; and even the hospital patient died in a violent paroxysm of the disorder, and after death the stone was found in the bladder. Now it is not in human nature to prefer a painful disorder to an easy remedy, and when men become tired of prosecuting the method devised for their cure, I much suspect that the physician is unequal to his task. In this situation I furnished myself with a very great variety of calculi, and began to make experiments upon them. I found them soluble in a small degree in Nooth’s fixed air apparatus; but I found, too, that they were equally soluble in water without fixed air; by very long standing, and moderate agitation, they may, in a great measure, be dissolved in any water. I then, for the first time, began to suspect that our reasonings and practical inferences were derived from false data, and immediately subjected calculi of every different appearance to chymical examination; and you know that my method of analysis does not change or destroy the component parts of the subject. I soon found that not one of them contained a single particle of calcareous earth; nor would it be easy to demonstrate that they contain any earth at all. They are all inflammable; they are all soluble in the nitrous acid, and from this solution no earthy precipitate can be obtained. In short, they seem to be similar to other animal substances. Convinced that mistaken principles had led us to erroneous practice, I began to look out for better; these must be learnt from the attentive observation of nature and from facts supported upon the basis of large experience; of course, the accessions must be slow: thus they stand at present.

The urine is a fluid composed of water, bile, and excrementitious animal substance: the animal substance is suspended in a state of solution in the water and bile. In the urine of a healthy man the suspension of the dissolved parts is perfect, both whilst the urine remains in, and after it has been ejected from the body; but when the menstruum is nearly saturated with the solvend, the abstraction of a few degrees of heat occasions a separation. The parts thus separated may be again dissolved by bringing the fluid into a warmer place. The separation of these parts is promoted by an irregular surface in the vessel: thus we observe that the incrustations are chiefly found upon the rougher parts. Every stone that I have examined appears to be formed upon a nucleus: this nucleus is most frequently a large piece of gravel that has passed down from the kidneys into the bladder: sometimes it is a little coagulated blood: but I believe any kind of solid would be sufficient, and I think it probable that no stone would ever be formed in the bladder if a nucleus did not previously exist to favour the deposition of the excrementitious animal substance. The sand or gravel that is found in the hollow of the kidneys is evidently a crystallization, and such crystals are sometimes formed in the urine when out of the body: these crystals do not essentially differ from the other deposited matter. These depositions and these crystallizations must depend either upon the menstruum being too weak, or in too small quantity to support the solvend in a state of solution, or else from the latter being from some cause or other unapt to remain dissolved. But these conditions do not seem to be induced by any very general causes. Dogs, horses, and men, or, in other words, carnivorous, herbivorous, and omnivorous animals are all subject to the stone. Whether the drink be hard or soft water, ale, beer, cyder, or wine, the disease will be produced, and very young children, who have scarcely tasted any thing but milk, are not exempt from it. In some patients, after the operation, the disease never returns; in others a new stone will be formed in the course of two or three years.

The bladder calculi, when cut through, appear to consist of concentric layers, and are undoubtedly formed by the opposition of parts: but the smoothness upon the surface of these coats or layers, their ready separation, their differing colors, and other observable circumstances, lead me to conclude that during the formation of these stones there has not been any uniform regular addition; but on the contrary, that a very considerable space of time must frequently have elapsed between the finishing of one coat and the formation of another.

The practical inferences deducible from these observations are—When a fit of the gravel, as it is called, is over, that is, when a concretion has passed from the hollow of the kidney down the ureter into the bladder, the patient must not be allowed to think himself well because relieved from pain: he must never be satisfied until he sees his enemy in his hand; and this may always be effected by teaching him to dilute freely, to retain his water until the bladder is considerably distended, and then to part with it in a proper position. If these simple rules were universally inculcated, I am persuaded we should not have many patients suffering from the stone. It must be the study of the physician to investigate those causes that occasion the excrementitious animal matter so readily to separate from its menstruum. I need not point out how various these may be; but if, independent of any peculiar attention of the physician or patient, the tendency to concretion is sometimes suspended for a considerable length of time, notwithstanding the existence of a nucleus, and at others altogether; surely we may be allowed to hope that we shall at length be able to produce and imitate these causes. I am persuaded that a deficiency of good bile is one very general cause of this tendency to premature separation, and I know from experience that bile is a solvend of urinary calculi. When the excrementitious secretion is not faulty in itself, but only separates for want of a proper quantity or quality of the menstruum, copious dilution is one obvious remedy: another is to divert this matter as much as possible from the kidneys, so as to discharge it by the skin. I am certain that nothing more effectually brings on an attack of the usual symptoms than a sudden check to the perspiration. In case of a stone already formed, I believe that if no further accretion was allowed to take place, it would soon be smoothed, and in time washed away or absorbed.