When joined to other medicines, it adds to their efficacy, or corrects the inconveniences they might otherwise produce. Thus, in fevers, as we have said, it greatly assists the action of opium: it promotes the solution of gum resins, resins, and oil. By this power it may probably mitigate the acrimony of drastic purgatives, a quality assigned to it by many authors. By the same effect it assists the absorption of mercurial ointment; and sometimes seems to render it, by external friction, an useful antispasmodic. It has been said to mitigate its action; but this is probably unfounded. Camphor has also been supposed to correct the inconvenient stimulus of cantharides; yet we suspect that it rather, by its sedative power, relieves the inflammation they excite. When united with them in the blistering plaster it seems not to prevent strangury.

It has been said, by a French author, that camphor may be given in a clyster, in a dose of two drachms, in inflammations, or other irritations of the bladder or uterus. We once injected a drachm, and at another time, half that quantity, but from each an alarming coma was produced. The patients were, indeed, relieved; but at the expense of such anxiety, that we have never dared to repeat the practice.

Externally applied, it has been useful, in very small proportions in ophthalmia; and in external tumours, united with spirit of wine. In this form, also, it has been used with fomentations to gangrened parts with success.

The dose of camphor has been variously directed. It has been said that it should either be given in large doses not under twenty grains; or if in smaller, that they must be repeated at short intervals, should any-sensible effects be expected. This, however, is too violent. In fevers, such large doses would be injurious from too great irritation, and we can seldom venture above six or eight grains. In nervous disorders this dose may be doubled: and in mania, twenty grains will not be too much. It may be divided and rubbed with nitre or sugar, and a few drops of spirits of wine; or united with mucilage of gum arabic, the camphor previously dissolved in a little spirit of wine, or expressed oil. Camphor, mixed with equal quantity of myrrh, makes an uniform solution in aqueous fluids; and this is the best mode of giving camphor in a liquid form, where myrrh may not be thought an improper combination with respect to the intent which we wish to produce. With the gum pills it readily unites, and it may be also formed into a convenient mass with the conserve of hips or stiff mucilage. This conserve most effectually covers it, if the form of a bolus is preferred.

An imprudent dose of camphor produces coldness of the extremities, vertigo, a small weak pulse, drowsiness, uneasiness about the precordia: but these effects are relieved by an emetic, followed with small doses of vinegar or other vegetable acids; and sometimes by mucilaginous drinks.

The camphorated emulsion may be prepared by adding a drachm of camphor to a pint of the almond emulsion, now called lac amygdala, almond milk; to mix the camphor, it will be necessary to use an additional quantity of the mucilage of gum arabic: a large spoonful, or more, may be given every two hours. Nitre, or acids, may be added, as the occasion may require. In the camphorated julep, little more than the smell of camphor is retained. The dose, in its best state, does not exceed a grain and a half.

The London college direct the following preparation of the camphorated mixture.

Take of camphor one drachm; rectified spirit of wine, ten drops; of double refined sugar, half an ounce; of boiling distilled water, a pint. Rub the camphor first with the rectified spirit, then with the sugar; lastly, add the water by degrees, and strain the mixture. This is better made by mixing the camphor with double its quantity of gum arabic, for thus it is less apt to irritate the stomach; a large spoonful contains about a grain of camphor. Vinegar may be added instead of water; as it renders the camphor more agreeable to the stomach, improves its antiseptic power, and renders it, according to Mr. Parteger, more successful in mania.

The emulsion and the mixture of camphor are useful in low and putrid disorders, being, in these cases, the lightest and best cordials, especially for women or feeble men affected with spasmodic symptoms; and this effect shows, that the medicine may be useful in the smallest doses.

The London college also order the following camphorated spirit for external uses:

Take of camphor, four ounces; of rectified spirit of wine, a quart; mix them so that the camphor may be dissolved. This is often successful in removing pains, inflammations, numbness, or palsy, by rubbing the part affected with it. An ounce of camphor will dissolve in an equal quantity of spirit; and in these solutions it does not evaporate, for the spirit must all be evaporated before the camphor will exhale.

The spiritus camphorae tartarisatus, is made by mixing equal parts of camphor and salt of tartar in a proper quantity of proof spirit, and drawing off one half. But this preparation does not possess any advantages above the sp. camphoratus.

The college of London used to add 3 i. of camphor to i. of the white ointment, and called it ung. alb. cam-phjrat.; but have now rejected it, though it is esteemed as cooling, emollient, and discutient, and useful against cutaneous heats, tettery, or serpiginous eruptions.

Different preparations are called oils of camphor, several of which may be seen in Neumann's Chemical Works, and other writers; but they do not appear to possess any peculiar advantage above the crude camphor.