This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
In acute diseases, this medicine is given from a quarter of a grain to one or two grains, and sometimes more, in conjunction commonly with nitre, or other substances of the antiinflammatory saline kind. Hoffman ob-serves (a), that it answers best on the approach of a crisis, or in the decline: that it is to be used with caution during the increase, and when the fever is at the height, more especially where the internal heat is great, moisture deficient, and the skin dry: and that it is sparingly to be given also when nature is weak; where a tumid-ness and redness of the face, with vertiginous complaints, torpor, and sleepiness, shew the vessels of the head to be distended; as also in palsies, convulsions, and in plethoric and costive habits.
(a) Diss. de usu camphorae securissimo & praestantissimo) & Med. rational. de febrib. passim.
In chronical disorders proceeding from a redundance of serous defluxions, or from an impurity of the humours, and as an assistant to mercurial alteratives, it is used more freely, and with less danger: in some cases a little opium is joined, which prevents the uneasiness which camphor of itself is apt to produce, and at the same time increases its operation by sweat, a mixture of camphor and opium being one of the most potent sudorifics. Some recommend camphor to be given in maniacal cases, to the quantity of half a dram every night or oftener; and instances have been produced (a) of this practice being attended with success.
It has been generally supposed that this concrete corrects the irritating power of cantha-rides; and Hoffman looks upon it as a corrector also of the stimulating cathartics and emetics. It apparently corrects, in a consider-able degree, the more active mercurial preparations; that is, it determines their operation to the cuticular emunctories, and by promoting their diaphoretic, restrains their purgative or emetic virtue: but how far it varies the action of cantharides, and the stimulants, purgatives, and emetics of the vegetable kingdom, is not as yet certainly known.
(a) Philosophical Transactions, n. 400. Suenska vetenskaps acad. bandl. tom. v. ann. 1744.
Camphor may be dissolved in watery liquors, and thus fitted for being commodiously taken, by grinding it with sugar, almonds, or thick mucilages, and adding the water by degrees. A dram of camphor, rubbed with a few drops of rectified spirit of wine till it grows soft, requires about four drams of fine sugar: a pint of boiling water is poured on this mixture, the vessel closely covered, and the liquor, when grown cold, drained out for use. Vinegar also, by this treatment, dissolves the camphor equally with water, and is often preferred in acute dis-eases, whether putrid or inflammatory, as rendering the julep somewhat more grateful both to the palate and stomach, and excellently coinciding with the medicinal intention. The whole of the camphor, however, is not dissolved by either; a part, and generally a considerable one, remaining behind upon the strainer. Almonds or mucilages render it completely dis-soluble into an emulsion or milky form. The above quantity of camphor requires about twelve almonds; to which mixture a pint of some suitable aqueous fluid, as the distilled water of pennyroyal, is commonly added, and half an ounce of fine sugar dissolved in the strained liquor. In this form, vinegar or other acids can have no place, as they coagulate the emulsion, or at least render it incapable of keeping the camphor dissolved: but nitre may be added in any quantity that may be thought proper, this neutral salt mingling uniformly with the liquor, and producing no separation of its parts. Emulsions made with mucilages admit both nitre and acids.
Mistura cam-phorat. Ph. Lond.
* Dr. Percival has lately discovered that camphor possesses the property of promoting the union of gummy-resinous substances with watery liquors; and also of uniting with, by triture, and liquefying, pure resinous substances, such as the balsam of Tolu. The detail of his experiments on this subject has been communicated to the medical society in London, and will be published in their next volume with some additional experiments by Dr. Chamber-laine.
A solution of camphor in rectified spirit of wine, in the proportion of an ounce to a pint, is employed externally against rheumatic pains and paralytic numbnesses, for discussing tumours and inflammations, and restraining the progress of gangrenes. On diluting this solution with watery liquors, the mixture becomes milky, and on standing for some time greatest part of the camphor separates. It has been said, that with the spirit of sal ammoniac made by quicklime, and with saturated alkaline lixivia, it mingles without separation: but, on trial, it turned milky with the former, in the same manner as with water; and with the latter it did not mingle at all, the camphorated spirit swimming distinct upon the surface of the alkaline lye. It has been reported also, that a camphorated spirit, uniformly miscible with water, may be obtained, by grinding the camphor with some-what more than equal its weight of fixt alkaline salt, then adding a proper quantity of proof spirit, and drawing off one half by distillation. This spirit, however, does not answer expectation: the quantity of camphor that rises with it is exceeding small, greatest part remaining behind in the distilling vessel: hence, though when the spirit is mixed with a large quantity of of water, it occasions no sensible turbidness, yet when mixed with only a little water, it exhibits the same appearances as the common solution, differing no otherwise than in degree.
Spiritus vini camphoratus Ph. Lond. & Ed.
The London college has now directed for external application a solution of camphor in the proportion of two ounces in a liquor composed of six ounces of the volatile spirit of sal ammoniac, and sixteen of simple spirit of lavender, united by distillation.
Camphor is used also in unguents, for burns, itchings, and ferpiginous eruptions on the skin. It is mixed in a larger proportion, with cata-plasms for the throat against inflammations of the uvula and tonsils; and dissolved, for rheumatic and other pains, in oil of olives, in the proportion of one part of camphor, to four of the oil. Hoffman reports, that a solution of camphor, in empyreumatic vegetable oils that have been rectified by distillation from quicklime, procures immediate relief in some kinds of violent pains (a).