The curative effects of remedies may be retarded, changed in form, or prevented, by untimely administration.

Remedies that are intended to act on the mucous membrane of the stomach only should be given when the organ is empty. If distant parts are to be affected in the most prompt and efficient manner, and the remedy is free from any distinctly irritating quality, it should also be taken on an empty stomach. As, when digestion is going on, the contents of the stomach are acid in reaction, if alkalies are administered, combinations take place, and salts are formed. Various organic substances are decomposed and, it often happens, rendered inert by the action of the stomach acid. If alkalies are introduced before digestion begins, diffusion of the acid-forming constituents of the blood no doubt takes place, and in this way the acidity of the gastric juice is promoted. The law of diffusion just given is equally applicable to acids; given before meals, they increase the diffusion of alkaline constituents of the blood toward the stomach.

The mineral acids, especially hydrochloric and phosphoric, increase the activity of pepsin when administered during the process of digestion, and alkalies given before digestion begins have the same effect to some extent, but, if taken during this process, retard or suspend it. Alcohol in considerable quantity lessens the activity of pepsin, but a small amount increases it. Five per cent, is probably the limit, and the larger the quantity beyond that the greater the injury to digestion (Klikowiz). The germicides or antiseptics interfere with the process of digestion in proportion to their power; hence the bichloride, the biniodide, and permanganates are the most injurious to pepsin. It follows that such agents should be given when the stomach is nearly or quite empty, free dilution serving to prevent injury to the mucous membrane. The sulphates, especially of the metals, nitrates, chlorates, bromides, salicylates, in the order named, decidedly lessen the ferment power of pepsin, and consequently retard digestion. None of these should be given during the period of digestion, but as long before or after as the circumstances will permit.

Remedial agents intended to enter the blood with the food must needs be given during the time when the conversion of foods is going on. Iron, the hypophosphites and phosphates, and certain lime-salts are of this character, but these remedies should be selected with reference to their action on the digestive fluids. Thus, according to the observations of Eccles, the hypophosphite of potassium, phosphate of iron, lactophosphate of calcium, citrate of iron, are among those exerting comparatively little effect on the process of digestion, while others, heretofore supposed to be free from injurious action, are especially hurtful. While the stomach contents are decidedly acid, those of the small intestine are alkaline, and sufficiently so to neutralize the stomach acid, and to maintain the alkalinity of the intestinal juices. When, therefore, it is required to have the medicament act on the small intestine, the best time to secure that object is when the flow of materials is in that direction, and, other things being equal, by combination with alkalies if the nature of the substance will permit.

Medicines intended to affect the hepatic and pancreatic secretions need to have ample time, and should be so administered as to begin their action when the periods of physiological activity arrive.

Applications to the Genito-Urinary Mucous Membrane

Brown-Séquard has proposed to utilize the bladder for securing absorption of remedial agents in cases of great intestinal disorder, as in cholera. Experiment has shown that morphine, for example, is taken up with considerable rapidity by this viscus.

Topical applications to the urethra and vagina are very frequently made, usually in the form of astringent injections. Suppositories, variously medicated, are also occasionally used in the treatment of affections of these parts.