This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Vitriolum & Calanthum Pharm. Paris. Vitriol: a saline crystalline concrete, com-posed of metal united with a certain acid called the vitriolic acid. There are three metals with which this acid is found naturally combined, zinc, copper, and iron: with the first it forms a white, with the second a blue, and with the third a green salt.
1. Vitriolum album Pharm. Lond. Vi-triolum album five Zinci Pharm. Edinb. White vitriol, or vitriol of zinc; found in the mines of Goflar, sometimes in transparent pieces, more commonly in white efflorescences; which are dissolved in water, and crystallized into large irregular masses somewhat resembling fine sugar; in taste sweetish, nauseous, and styptic.
The common white vitriol of the shops contains a quantity of serrugineous matter; of which, in keeping, a part is extricated from the acid, in an ochery form, so as so tinge the mass of a yellow hue. On dissolving the whitest pieces in water, a considerable portion of ochre immediately separates: the filtered solution, transparent and colourless, becomes again turbid and yellow on being made to boil, and deposites a fresh ochery sediment; and a like separation happens, though much more slowly, on standing without heat. Hence, when the solution is evaporated to the usual pitch, and set to crystallize, the crystals generally prove foul; unless some fresh acid be added (as an ounce of the strong spirit or oil of vitriol to a pound of the salt †) to keep the ferrugineous matter dissolved: this addition both secures the whiteness of the crystals, and prevents their growing soon yellow in the air. White vitriol generally contains also a small portion of copper, distinguishable by the cupreous stain which it communicates to polished iron immersed in solutions of it, or rubbed with it in a moid state. The quantity of this metal is so exceedingly minute, that it is not, perhaps, of any inconvenience in the intentions for which white vitriol is commonly employed: the separation, if it should be thought necessary, may be effected, by boiling the solution for some time, along with bright pieces of iron, which will extricate all the copper: by continued or repeated codtion, greatest part of the ferrugineous matter also may be separated.
White vitriol is sometimes given, from five or six grains to half a dram and more, as an emetic; and appears to be one of the quickest in operation of those that can be employed with safety. Its chief use is for external pur-poses, as a cooling restringent and desiccative: a dilute solution of it, as sixteen grains in eight ounces of water, with the addition of sixteen drops of weak vitriolic acid, is an excellent collyrium in defluxions and slight inflammations of the eyes, and, after bleeding and purging, in the more violent ones: a solution of it with alum, in the proportion of two drams of each to a pint of water, is used as a repellent fomentation for some cutaneous eruptions, for cleans-ing foul ulcers, and as an ejection in the fluor albus and gonorrhoea when not accompanied with virulence. This vitriol is sometimes like-wife employed as an errhine, and said to be a very effectual dissolvent of mucous matters; in which intention it is recommended, in the German ephemerides, against obstructions of the nostrils in new-born infants.
† Zinc, vitriol, purif. Ph. Lond.
Aqua vitrio-lica Ph. Ed.
Aqua alumi-nis comp. Ph. Lond.
2. Vitriolum CaeEruleum Pharm. Lond. Vitriolum caruleum five cupri Pharm. Edinb. Blue vitriol, or vitriol of copper, commonly called Roman or Cyprian vitriol, or blue-done. This kind of vitriol is in many places produced from sulphureous ores of copper: the acid of sulphur is no other than the vitriolic; and the inflammable principle of the sulphur being dissipated either by fire or by a spontaneous resolution of the mineral, the acid remains combined with the copper (see Pyrites): the vitriol, now formed, is either extracted by the application of water, or washed out by rain or sub-terraneous waters: hence in some copper mines are found blue waters, which are true vitriolic solutions of copper, and which deposite that metal on the addition of iron or of any other substance which the acid more strongly attracts. The greatest part of the blue vitriol, now met with in the shops, is prepared in England, by artificially combining copper with sulphur or its acid.
The vitriol of copper is of an elegant sap-phire blue colour; hard, compact, and semi-transparent; when perfectly crystallized, of a flattish, rhomboidal, decahedral figure; in taste extremely nauseous, styptie, and acrid. Ex-posed to a gentle heat, it first turns white, and then of a yellowish red or orange colour: on increasing the fire, it parts, difficultly, with its acid, and changes at length to a very dark red calx, reducible, by fusion with inflammable fluxes, into copper.
This salt, like the other preparations of copper, acts, in doses of a few grains, as a mod virulent emetic. Its use is chiefly external, as a detergent, escharotic, and for restraining hemorrhagies: for which last intention, a strong styptic liquor is prepared in the shops, by dis-solving three ounces of blue vitriol and three of alum in two pounds of water, then adding one ounce and a half of oil of vitriol, and filtering the mixture for use.
*Blue vitriol has of late been considerably employed as an emetic by some practitioners; and is said to be by no means an unsafe one, as it operates the instant it reaches the stomach, before it has time to injure by its corrosive quality. The peculiar advantage in using it is represented to be, that it has no tendency to become also purgative, and that its astringent power prevents the tone of the stomach from being impaired after vomiting with it. It is much recommended in the early state of tubercles in the lungs; and the following method of exhibition is directed (a). Let the patient first swallow about half a pint of water, and immediately afterwards, the vitriol dissolved in a cup-full of water. The dose may be varied according to age, constitution, etc. from two grains to ten, or even twenty; always taking care to begin with small ones. After the emetic is rejected, another half pint of water is to be drunk, which is likewise speedily thrown up, and this is commonly sufficient to remove the nausea.
(a) Simmons, on the Treatment of Consumptions, p. 70.