†Prof. Adolph Gubler.

and meconate. As a rule, when medicine is taken into the system a series of chemical changes ensue from the moment of its ingestion to the period of its elimination. This is effected by its coming in contact with the acids, alkalies, and alkaline chlorides, and other chemical constituents that have their habitation in different parts of the system. Owing to the systemic changes in health and disease, in fasting and feasting, and other circumstances, these chemical reactions likewise meet with corresponding changes. If these systemic chemicophysiological operations were always the same, there would be no change in the vital forces, and medicine could be administered with uniform results. The frequency and extent of these systemic chemical oscillations may not always receive the proper attention, and therefore may cause confusion in theory and disappointment in practice. M. Andrei considers mucus to be acid; Booth believes it to be alkaline. The former thinks the pancreatic juice alkaline, and Turner has it acid. Such are the discrepancies we find as to the chemical nature of nearly all the secretions of the human body. The fact is. they may be all right, under peculiar circumstances. It is known that the secretions of the mouth may be alkaline after food is taken, acid, and even poisonous after fasting; the urine may be acid, and then alkaline, or acid in the kidneys, and alkaline in the bladder; the chyle may be acid in the small intestines, but is alkaline in the lacteals; sweat is acid, but from a skin in a state of inflammation it becomes alkaline, etc.

It is in these chemico physiological changes that many of the inequalities are produced in the effects of medicine - why it is that one remedy will give a marvelous relief in one case, while in another, apparently with the same pathogenic condition and the same constitution, may prove the instrumentality of harm.

The first, and often the most important chemical change that a medicine undergoes in the stomach, is in its contact, with thejlactic, chlorhydric or phosphoric acids, or its normal and abnormal ferments. Some are made soluble, and form a close affinity with the acid secretions of the stomach and its contents, some bear no modification whatever, others pass through a decomposition into a new compound.

The acids in the stomach exert great influence. They increase the solubility of salts, for the majority of salts are rendered more soluble by an excess of acid. Bases are also salified by those acids. Thus, the oxides of iron, of zinc, and of calcium are salified and dissolved by the acids contained in the stomach. With regard to iron, this is of great importance, because we very frequently introduce oxides of iron, relying upon the acids in the stomach to effect their solution and procure their passage into their circulation. The acids in the stomach also decompose such carbonates as those of lime, soda, potash, magnesia, and iron rust. Consider how important are these facts. When you desire to diminish the gases and acids of the stomach, you must not prescribe carbonate of magnesia, but calcined magnesia. The carbonates would only have a tendency to increase the disorder by producing carbonic acid gas.*

A most important feature of medicines in the stomach is their conversion into new compounds. Thus, the cyanide of potassium is converted into prussic acid. The nitrate of silver into a chloride. The citrate of bismuth and ammonia is precipitaled by the hydrochloric acid, which it meets in the gastric juice, and is consequently reduced to the condition of the insoluble salts of the subnitrate and sub-carbonate, † The therapeutic doses of permanganate of potassium are entirely decomposed in a very short time after they reach the stomach, hence any action which the drug exerts upon the general system is due to the oxide of manganese; indeed, the ordinary black oxide of manganese is affirmed by different practitioners to be as active an emmenagague as is the permanganate.‡

When the oxide of zinc absorbs lactic or hydrochloric acids in the stomach, the chloride of zinc is then formed, which is a salt possessed of highly irritating, nauseating and emetic qualities; therefore the oxide of zinc should be associated with bicarbonate of soda, that the acids from the stomach may be more speedily absorbed.§ Many forms of iron undergo a change to ferreous chloride before being absorbed in the hydrochloric acid of the gastric juice, while others, like the ferric salts, undergo a partial reduction. Bromine and iodine are much alike in their chemical changes in passing through the system. The bromine in an uncombined form unites with the soda or potassa found in the secretions of the body, forming a neutral salt of bromide, or bromide of sodium or potassium. The efficacy of iodine is greatly impaired by all starchy food, and should be administered before eating, unless to neutralize its irritating effects on the stomach. The sulphites taken internally are not decomposed in the stomach ordinarily. If otherwise, there is a manifest production of sulphurous acid gas, when a little magnesia should be added to the sulphite to neutralize the acids of the stomach. Sulphites are readily absorbed, and appear in the urine unchanged in about twenty minutes after they have been swallowed; but they are readily changed in the system into sulphates. ||

The Time for the Administration of Certain Medicines.

Taking into consideration the reacting influences between a medicine introduced into the stomach and the secretions of that organ, we are led to inquire, when is the most propitious time to introduce a medicine into the stomach, fasting or at meal time? On the authority of Gubler: "The only remedies introduced at meal times are those requiring previous dissolution, those acting in the same as histogenics, and metallic substances from which the metal is alone desired, such as iron, manganese and arsenic. Organic substances, as a rule, are usually administered on an empty stomach." A better rule is, that nearly all remedies of a high power, or of a heterogeneous nature, had best be given on a full stomach. Take any powerful medicine, it will not always have the same effect by giving it either way. Strychnine in a maximum dose, on an empty stomach, may readily manifest its toxic influence, but it would take more than double the dose to secure the same effect by giving it after eating. The difference is, that medicine taken before or after eating is not disposed of by the same physiological operation. A medicine administered after eating finds its way gradually into the system, through the ordinary process of assimilation, and often with better effect, with a less toxic tendency or intolerance than when taken on an empty stomach. A soluble medicine in an empty stomach is rapidly absorbed by the veins of that organ, or rather by endosmosis. It is obvious that medicines administered before and after eating do not find their way into the circu- lation by the same avenues, and by the same physiological action; and the effect of a medicine introduced into the system, either by a gradual or rapid process, may be a question of the greatest importance in a clinical point of view.

*Prof. Adolph Gubler. Prof. H. C. Wood. ||Waring.

†Prof. R. T. Edes.

§ Prof. Adolph Gubler.

To show that remedies at different times have different effects in connection with eating, we have simply to cite the effects of bicarbonate of potassium and other alkaline carbonates on the stomach - on an empty stomach they increase the acidity of the system, while their administration after a meal diminishes it.

Iodine and iodides should be given on an empty stomach. If given during digestion, the acids and starch alter and weaken their action. Acid, as a rule, should be given between meals; acids given before meals check the excessive secretions of the acids of the gastric juice. Oxide and nitrate of silver should be given after the process of digestion is ended. If given during or close after meals the chemicals destroy or impair their action. Potassium permanganate also should not be given until the process of digestion is ended, inasmuch as organic matter decomposes it, and renders it inert. Malt extracts, cod liver oil, the phosphates, etc., should be given with or directly after food.*

There are other considerations why a proper time should be selected in giving medicines in relation with eating. It is known that various preparations possess the power of precipitating the peptones of food, or of destroying the activity of pepsin, such as corrosive sublimate, alcohol, tannin, etc., and these should be, therefore, ordered to be taken between, rather than just before a meal.† This should be carefully remembered in the treatment of adynamia, and where it is of the utmost importance to maintain a normal gastric digestion. We have not only to foster gastric digestion, but to make our best efforts to restore it when depressed by some constitutional disease; this is better accomplished by medicating more for the disease, than the functional derangement it may cause in the stomach. It is well known that in impaired digestion and deficient interstitial nutrition, accompanying certain blood diseases, which produce anaemia, or a diminution of the red blood corpuscles, for instance, the syphilitic and cancerous cachexia, iron will not, as a rule, repair the anaemic condition while in the former disease, certainly mercury and iodide of potassium, and in the latter sometimes, carbonate of ammonia or potassa will improve the anaemia.*

*Gaillard's Medical Journal. †Waring.