Active Ingredients. - The woody portion of the root of the ipecacuanha plant is nearly inert; that which gives value to it in medicine being the bark. Both portions contain the essential alkaloid, emetine, but in an impure condition.

Pure emetine constitutes about one per cent. of the best ipecacuanha root; when separated it is a white and amorphous powder, inodorous and of bitter taste, and is found to consist of C35H15O9N. It is soluble in alcohol; scarcely soluble in ether and oils, very sparingly soluble in cold, but much more soluble in hot water. It dissolves in acids, is precipitated by tannin, and is fusible at 122° F. Perfectly pure emetine is procurable only with difficulty.

The impure form is distinguished by its grayish-yellow color, and occurs usually in transparent scales. In taste it is bitter and acrid; it is nearly destitute of odor, very soluble both in water and in alcohol, but insoluble in ether.

In addition to the peculiar alkaloid emetine, ipecacuanha contains an astringent acid, C14H9O7, somewhat akin to catechine, and called cephaelic or ipecacuanhic acid. There is also a trace of volatile oil, with some fatty matter, and a small proportion of starch and gum. The cephaelic acid was formerly mistaken for gallic acid. With the persalts of iron it strikes a green color.

Physiological Action. - In all the more decided effects which ipecacuanha can produce in the animal organism, its powers are fairly represented by the alkaloid emetine, though the latter is not convenient as a remedy. The experiments of Merat and De Lens, of Magendie and Pelletier, and of Schroff with the pure alkaloid, and of Magendie and Pelletier and others with the impure, bring out substantially the same results with those obtained by the action of powerful doses of ipecacuanha itself, the only question being one of degree. 1. It is a local irritant both to the skin and the mucous membrane. 2. In large doses it is a special irritant after absorption (for instance, from the subcutaneous tissue quite as well as if swallowed) to the gastric and intestinal mucous membrane. 3. It has a powerful and, in large doses of the alkaloid, a fatal, depressing action upon the nervous centres.

How far the vomiting, which is so characteristic an effect of full doses of ipecacuanha, and the striking increase of secretion from the mucous membrane of the bronchi and the stomach which are similarly produced, are consequences of the direct action of the drug upon the vagus-terminals, or are brought about by action upon the nervous centres, is not at all known. There is a well-known phenomenon produced by the inhalation of ipecacuanha dust; in ordinary persons this produces merely cough and sneezing, and might be attributed merely to the local irritant action; but in certain subjects - and they are probably more numerous than is generally supposed - the sneezing, coughing, and running at the eyes and nose are supplemented by an amount of dyspnoea and feeling of anxiety which is comparable to that caused by an attack of spasmodic asthma or of the more spasmodic form of hay-fever. In these points of view there is great interest in the experiments of Pecholierwith emetine, on rabbits; a dose .072 grain caused immediate excitement, followed by retching and (in two minutes) a remarkable feebleness, depression of circulation and breathing, together with a very curious lowering of temperature in the whole anterior half of the body, while the rectal temperature was raised from local congestion. If this dose were repeated daily for some time, it was found that the singular temperature-phenomena became more marked, while the excitement and the retching were less so, and death at last took place.

Dissection showed congestion, intense in the stomach and milder in the upper part of the intestines; the lungs were anaemic; the liver contained no glucose. The same results were produced when the remedy was given by the skin.

It must, after all, be confessed that, as Nothnagel remarks, we are in an astonishing state of ignorance of the physiological action of a drug which medical men have so largely employed for centuries past.

Therapeutic Action. - Fortunately it happens that our information, though in a great measure empirical in its source, enables us to say with confidence that ipecacuanha is highly useful in various ways.

As an Emetic, ipecacuanha is unequalled in its value for a large number of cases. It is not violent, nor swift in action, but very certain; it is mild, and the vomiting it causes usually empties the stomach, and is neither repeated nor followed by the collapsed state which antimony and some other emetics often leave behind them.

Its freedom from any disgusting taste, like that of sulphate of zinc or sulphate of copper, renders it still further advantageous for administration to children. Twenty grains of the powder, or half an ounce of the wine for an adult, and from one-fourth to one-half these quantities for a child, will rarely fail to act, but if necessary may be repeated in fifteen or twenty minutes.

As an anti-Catarrhal remedy, ipecacuanha has extensive and varied uses; for there is perhaps no part of the mucous tracts the catarrhal affections of which may not be beneficially treated with this drug.

Common Catarrh of the throat and bronchi in the dry stage may be beneficially treated with nauseating or nearly nauseating doses of the drug; thus from one to two grains may be given every two or three hours. The smaller dose will induce diaphoresis, and probably also give some relief to the dryness of the mucous membrane; the two-grain doses will cause a decided increase in the flow of mucus, and in most patients a feeling of nausea, or at least of squeamishness; but at the same time much relief will be obtained for the distressing dry soreness.

There is a different use for ipecacuanha in the later stages of bronchial catarrh, where the secretion is profuse and troublesome. It is then to be given in much smaller doses, and thus given it unquestionably possesses power to limit the mucous secretion and to improve its quality, diminishing the nasty ropiness which makes it so offensive and also so likely to keep up irritation. The doses I now refer to are one-quarter to one-half grain of the powder, or five to ten minims of the wine. Smaller doses must be given to children, but not in the exact proportion of their age, for children usually bear ipecacuanha very well.