The alkaline carbonates are found to answer as effectually as the pure alkalies, and they have the advantage of being less liable to disagree with the stomach. Mr. Hatchett has proposed the carbonate of magnesia, in doses of ℈j to ʒj, as a valuable substitute for alkaline remedies in cases of lithic calculi; but as its insolubility must render its absorption equivocal, the beneficial operation of the substance must principally depend upon its neutralizing any excess of acid in the primæ viæ, and in this way there can be no doubt of its lithonthryptic agency; “but,” says Dr. Marcet, “such is the tendency which the public has to over-rate the utility of a new practice, or to take a mistaken view of its proper application, that there is every reason to believe that the use of magnesia has of late years become a frequent source of evil in calculous complaints.” Lime-water has been also recommended for the purpose of fulfilling the same indications, and as not being liable to produce that irritability of stomach which frequently attends the long continued use of the fixed alkalies; besides which, some chemists have maintained that it exerts a peculiar solvent power over the cementing animal matter of the concretion, and thereby destroys its cohesion.[[207]]
Where an acid is indicated, the Muriatic will in my judgment be found as convenient and effectual as any that can be administered. Mr. Brande proposes Cream of Tartar for this purpose; upon this point I differ with him, for this salt, to say the least of it, is questionable in its mode of operation; for although its first impression upon the stomach is that of an acid, the subsequent processes of digestion decompose it, and eliminate its base, which being absorbed acts upon the urinary organs as an alkali. I have seen a white sabulous deposit, consisting of the Phosphates, in the urine of persons after the constant use of Imperial as a beverage, which I am at a loss to explain upon any other principle. Sir Gilbert Blane has also very satisfactorily shewn, that a fixed alkali produces the same effect upon the urinary organs whether it be exhibited alone, or in combination with citric acid; in this latter case the salt undoubtedly undergoes a decomposition in transitu, as I have more fully explained under the consideration of Diuretics, (page 94.) During an alterative course of Lithonthryptic remedies it may be beneficial to interpose occasionally a purgative medicine, but we must not combine it with the lithonthryptic, at least, if we wish this latter medicine to reach the urinary passages; for it is a law which I have already attempted to establish (see page 94), that Catharsis suspends the process of alimentary absorption.
There remains to be considered another mode of applying a solvent, and which would seem on the first view of the subject to be full of promise,—that of injecting the proposed menstruum into the bladder. Unfortunately, however, the irritable state of this organ will generally preclude the possibility of preserving the menstruum, for a sufficient length of time, in contact with the calculus to accomplish any material solution; nor am I aware that any case, in favour of such a practice, stands recorded. An ingenious and novel application of the powers of Electro-chemistry has been lately[[208]] proposed by M M. Prevost and Dumas, as capable of affording means for the solution of the calculus within the bladder; the suggestion is highly plausible, and ought not to be hastily rejected without trial. Could the functions of the part be protected against the influence of so powerful an agent, it is evident that, by a galvanic battery of sufficient intensity, a calculus composed of alkaline or earthy salts might be transferred from the bladder by the simple introduction of a double sound, communicating on one hand with the calculus, and, on the other, with two vessels filled with water, in which are plunged the opposite poles of a galvanic apparatus.[[209]] This arrangement would transfer the acid constituents into the vessel connected with the positive end, and the bases into that of the negative end. So far, however, as the experiments have hitherto been carried, this degree of galvanic operation would seem to excite too much irritation in the bladder to be admissible; but it still offers a resource of an apparently more practicable nature. This consists in giving to the calculus a tendency to crumble from the slightest force; such a friability, in short, as shall render it easily broken into pieces sufficiently small to be evacuated through the urethra, especially by the aid of dilating that passage, an operation upon which much has lately been said and written. A fusible calculus from the human subject was submitted to the action of a pile, consisting of 120 pairs of plates, for twelve hours in succession. The platinum wires, constituting the poles, were placed in contact with the calculus, about six or eight lines distant from each other, and the whole plunged in a vessel filled with pure water. During the galvanic action, the bases and phosphoric acid first arrived at their respective poles, then re-entered into combination, when the salt thus reformed was precipitated in the state of powder. The calculus weighed 92 grains before the experiment, and was reduced at its termination to 80. The process being continued, at the end of sixteen hours it presented a mass of such friable texture as to be reduced into small crystalline particles by the slightest pressure; the largest of which did not exceed the size of a lentil, so that it might have easily passed through the urethra.
In order to ascertain how far this decomposition could be effected in the living body, the ingenious experimentalists selected a dog of rather large size, into whose bladder they introduced a fusible calculus attached to a sound, and between two conductors of platinum; the bladder was next distended by injecting tepid water, and the apparatus subjected to galvanic influence. After a little struggling, the animal became calm, and was subjected to the operation during an hour. On removing the sound, the calculus shewed unequivocal marks of decomposition. The same process was repeated, night and morning, during six days, when the friability of the calculus rendered it impossible to continue the experiment. It had lost weight in the same proportion as in the preceding trial. The bladder, which was afterwards examined, exhibited no appearance of injury or disease.[[210]] The authors assert that this organ does not suffer any inconvenience from this more moderate degree of galvanic action, and suggest, as a proof of the mildness of its influence, that we should immerse the tongue in a vessel filled with water, in which a calculus is undergoing decomposition, and it will be found that the tongue, which is far more sensible than the bladder, will scarcely perceive the galvanic action, even when decomposition is going on briskly. The authors add, that this process cannot offer any advantage for the removal of those calculi which consist wholly of Uric acid, or which contain a large proportion of it.[[211]]
ANTIDOTES.
Synon: Alexipharmics. Alexiterials. Counter-poisons.
Medicines which are capable of preventing the ill effects of a poison; or, of counteracting its fatal virulence.
There is perhaps no subject upon which the credulity of mankind has been so extravagantly exercised as on that of Poisons; nor is there, certainly, any class of remedies whose history has suffered so many vicissitudes from the caprice of hypothesis, as that of Antidotes.[[212]]
It is not my intention, on the present occasion,[[213]] to enumerate the many extraordinary virtues[[214]] which credulity has, at different times, assigned to such medicines; nor shall I consume the time of the reader by attempting to expose the absurdity of those fearful powers with which ignorance, terror, and imposture, have invested certain poisons,—a subtlety so extreme as to defeat the most skilful caution, and a virulence so manageable as to be capable of the most accurate graduation; so that while the former attribute was believed to ensure their deadly operation, although exerted through the most secret and least suspicious medium, as that of gloves,[[215]] tapers, or letters, the latter was said to enable the accomplished assassin to measure the allotted moments of his victim with the nicest precision, and to occasion his death at any period that might best answer the objects of the assassination.[[216]]
The abandonment of such notions may be considered as one among the many advantages which have arisen to medicine, from the cultivation of physiology.