Acid solutions directly introduced into the bladder stand in a very different position to the calculus from those which, having been swallowed and having traversed the alimentary canal, now enter the blood and circulate the system in a state of extreme dilution. In the former case the solvent and the substance to be acted upon are brought immediately into contact with each other without having been exposed to any possible source of decomposition, and in this instance the two chemicals are placed under conditions which invariably yield a definite known result. On the other hand, we have no assurance whatever that the acid which enters the mouth ever reaches the bladder in an uncombined state. On the contrary, the absence of any therapeutical response to the continuance of the remedy, as well as a knowledge of the chemical reaction of the secretions (salivary, biliary, pancreatic, etc.) with which it must be brought into contact in its course towards the blood, all go to suggest its speedy neutralization and consequent inertness as a stone solvent. Clear as may be the chemical action of acids on calcic carbonate, and constant as is the composition of equine vesical calculus, there are nevertheless serious objections to the general employment of such remedies in the treatment of stone. In the first place, the strength of the solution injected into the bladder must at all times be so weak as to produce the feeblest solvent action, or the already irritable, and perhaps eroded, mucous surface will be excited to inflame and lead to renal complications and other untoward results. To be effectual, therefore, a frequent and prolonged application of the remedy is indispensable.
The operation of injecting the bladder is clearly one which cannot be entrusted to lay hands, and if carried out to meet the necessities of the case by a qualified surgeon, must involve considerable outlay, to say nothing of the trouble, risk, and loss otherwise sustained. Obviously then the remedia Uthontriptica becomes, for all practical purposes of stone, a dead letter, and must be relegated to the limbo of exploded fables.