Antilithics^[182] are remedies which have the power of preventing the formation of those mechanical deposites from the urine, which give origin to calculous concretions; and may belong either to the class of Vital, or Chemical Agents.

Lithonthryptics^[183] are those medicines which, by a chemical operation, are capable of dissolving calculous concretions.

It has been already shewn, while treating the subject of Diuretics, that certain substances, when internally administered, are capable of passing the barriers of digestion, and of entering the circulation; and that, moreover, these bodies may be again separated by the secretory vessels of the kidneys, and be ejected from the body in the urine. It cannot therefore be contended, that the urinary calculus is placed beyond the sphere of direct medicinal influence, nor can any argument, founded upon the alleged incompatibility of chemical and vital action, be fairly maintained in this case; for the urinary calculus, as well as the urine itself,^[184] may very justly be considered as extraneous to the living body. The existence of such a class of remedies as that of Lithonthryptics being thus established, we have to consider the mode and possible extent of their operation in the different varieties of the disease, which they are thus calculated to palliate or cure. In entering upon this inquiry, it is not my intention to prosecute the subject farther than may be necessary to explain the modus operandi of the remedies in question, and in conformity with the object and plan of this work, to establish some general principles that are to direct us in their election, combination, and administration; for farther details the practitioner must consult the systematic treatises of Prout^[185] and Marcet,^[186] and the very able papers of Mr. Brande,^[187] and Dr. Wilson Philip.^[188]