Page images
PDF
EPUB

Melt the Rubber at a temperature not exceeding 150° C. (302° F.); add the Petrolatum, and continue the heat until the Rubber is dissolved. Add the Lead Plaster to the hot mixture; continue the heat until it becomes liquid, then strain, allow it to cool, and stir until it stiffens.

Remarks. This new official is the first attempt of the United States Pharmacopoeia to introduce a rubber plaster base. The amount of rubber (2 per cent.) is quite small, however, and therefore quite different from the rubber-base medicinal plasters of the manufacturer. It is, however, similar to the commercial rubber adhesive plaster (sticking plaster) which is spread by machinery on a large scale.

The apparatus consists of reels on one of which the original bolt of cloth is placed; the unrolled cloth passing between the lower plate of stone or metal, and a receptacle containing the melted plaster mass; one side of the receptacle consists of a dull steel blade resting

or inch above the slightly stretched cloth. The melted mass trickles upon the cloth in a broad stream, covering the entire width of the cloth, save a small marginal edge. As the soft mass flows upon the cloth it is rapidly passed between the spreading apparatus described above, and emerges from the same with a thin and uniform coating of the plaster material.

EMPLASTRUM BELLADONNÆ. Belladonna Plaster.

Belladonna Plaster should contain not less than 0.38 per cent. nor more than 0.42 per cent. of mydriatic alkaloids.

Recipe.-Extract of Belladonna Leaves, three hundred

[blocks in formation]

300 Gm.

700 Gm.

To make about one thousand grammes.. 1000 Gm.

Melt the Adhesive Plaster on a water-bath, add to it the Extract of Belladonna Leaves, softened by the heat of a water-bath, and continue the heat, stirring constantly until the mixture is perfectly homogeneous; then allow it to cool.

Spread Belladonna Plasters made with a rubber base should yield, when assayed, not less than 0.38 per cent. nor more than 0.42 per cent. of mydriatic alkaloids.

Remarks. This plaster mass is made by combining extract of belladonna with adhesive plaster. This is the only plaster directed by the pharmacopoeia to be of assayed strength to 12 of 1 per cent. mydriatic alkaloids. Details of assay will be given in Chapter LV.

38

EMPLASTRUM CAPSICI. Capsicum Plaster.

Recipe.-Oleoresin of Capsicum, twenty-five hundredths of a

gramme....

42

0.25 Gm.

Adhesive Plaster, spread on fabric, a sufficient quantity.

Apply the Oleoresin of Capsicum to the surface of the Adhesive Plaster by means of a brush, so as to form a thin coating over an area fifteen centimeters square, leaving a margin around the sides.

Remarks. As already mentioned, this is the one plaster in the official recipe of which are given explicit directions as to spreading, the object being uniformly to distribute the oleoresin of capsicum as well as to limit the amount of this irritating substance employed. The oleoresin is chosen in preference to the drug because the latter, blended with the plaster base, would soon lose its activity. For this reason these plasters should be dispensed freshly prepared.

[blocks in formation]

Triturate the Mercury with the Oleate of Mercury until the former is thoroughly divided, then add the Hydrous Wool-Fat, and continue the trituration until globules of Mercury are no longer visible. Add the mixture to the Lead Plaster, which has previously been melted in a tared dish, and incorporate thoroughly, adding, if necessary, sufficient Lead Plaster to make the product weigh one hundred grammes.

Remarks. In this plaster the mercury is extinguished with oleate of mercury and hydrous wool-fat and then mixed with lead plaster.

EMPLASTRUM OPII. Opium Plaster.

Recipe.-Extract of Opium, six grammes.
Water, eight cubic centimeters..

Adhesive Plaster, ninety grammes..

6 Gm.

8 Cc.

90 Gm.

To make one hundred grammes.. 100 Gm.

Rub the Extract of Opium with the Water until it is uniformly soft; add it to the Adhesive Plaster, which has been previously melted in a tared dish on a waterbath, and continue the heat with constant stirring until the product weighs one hundred grammes.

Remarks. This plaster contains 6 per cent. of opium mixed with adhesive plaster.

EMPLASTRUM PLUMBI. Lead Plaster.

Recipe and details of manufacture of this important plaster base, as well as full explanation of the chemistry of manufacture, will be given in Part VII.

EMPLASTRUM SAPONIS. Soap Plaster.

Recipe.-Soap, dried, and in a coarse powder, ten grammes..
Lead Plaster, ninety grammes...
Water, a sufficient quantity,

10 Gm.

90 Gm.

To make about one hundred grammes.. 100 Gm.

Rub the Soap with enough Water to reduce it to a semiliquid state; then mix it with the Lead Plaster previously melted, incorporate thoroughly by stirring, and evaporate to the proper consistence.

Remarks. This plaster mass is lead plaster softened by addition. of 10 per cent. soap.

Of the plasters dropped at the last revision, but two are worthy of notice.

EMPLASTRUM ICHTHYOCOLLÆ (U. S. P. 1890). Isinglass

Plaster.

This is made by spreading aqueous solution of isinglass by means of a brush upon taffeta, successive layers of isinglass being applied to this fabric (a variety of silk) until the coating is sufficiently thick.

The last portion of isinglass solution is mixed with alcohol and glycerin and applied in the same manner. The back of the taffeta is then spread with tincture of benzoin, and the official plaster allowed to become perfectly dried. Isinglass plaster is the well-known courtplaster, and is intended for adhesive purposes in simple operations, such as bringing the two edges of open cuts together. It has no medical action.

EMPLASTRUM PICIS BURGUNDICE. Burgundy Pitch Plaster.

This is made by softening Burgundy pitch with yellow wax and olive oil, the Burgundy pitch being so brittle that, if melted and spread on cloth by itself and allowed to become quite cold, the finished plaster will break very quickly. Burgundy pitch plasters formerly enjoyed a large sale under the name of "poor man's plasters."

PAPERS

Papers are a class of pharmaceuticals in which the medicine is either spread upon paper or absorbed by it.

But one paper is recognized by the present pharmacopoeia.

CHARTA SINAPIS. Mustard Paper.

Recipe.-Black Mustard, in No. 60 powder, one hundred

[blocks in formation]

100 Gm

10 Gm

Pack the Black Mustard in a conical percolator, and gradually pour Petroleum Benzin upon it until the percolate ceases to produce a permanent, greasy stain upon blotting paper. Remove the powder from the percolator, and dry it by exposure to the air. Having meanwhile dissolved the Rubber in a mixture of one hundred cubic centimeters, each, of Petroleum Benzin and Carbon Disulphide, mix the purified mustard with a sufficient quantity of the solution to produce a semiliquid magma, and apply this, by means of a suitable brush, to one side of a piece of rather thick, well-sized paper, so as to cover it completely, and then allow the surface to dry. A surface of sixty square centimeters should contain about 4 Gm. of Black Mustard deprived of oil.

Before it is applied to the skin, Mustard Paper should be dipped in warm water for about fifteen seconds.

Remarks. This paper is prepared by mixing powdered black mustard (which has been freed from oil by percolation with benzin) with a solution of India rubber in benzin and carbon disulphide, and spreading the semiliquid magma on a piece of stiff well-sized paper (by means of a suitable brush), the pharmacopoeia requiring that 60 square centimeters of such paper should contain about 4 Gm. of black mustard deprived of oil. The object of first extracting the mustard with benzin is to free it from the fixed oil naturally existing in the seed, and which, if permitted to remain in the mustard paper, would rapidly cause it to become greasy and disagreeable to handle. Mustard paper (mustard leaves, as they are called) affords an elegant and convenient method of applying the mustard plaster. When such a mustard leaf is dipped into warm water, a chemical action sets up between the ferment myrosin and the glucoside potassium myronate,

naturally existing in the mixture, with the formation of the volatile oil of mustard (see p. 747). The pharmacopoeia directs that the leaf be dipped in warm water, since dipping it in cold water retards the chemical action to a certain extent. On the other hand, it is far preferable to dip into cold water than into hot water, and under no circumstances should the mustard paper be moistened with boiling water, as the heat is sufficient to destroy the delicate ferment, myrosin, and thus prevent the formation of the volatile oil.

Mustard leaves are applied externally as a rubefacient and local irritant, being particularly adapted for cases of acute indigestion. There was one other paper recognized by the pharmacopoeia of 1890.

CHARTA POTASSII NITRATIS (U. S. P. 1890). Potassium Nitrate Paper.

This is made by dipping white, unsized paper (either filter-paper or blotting-paper) into an aqueous solution of potassium nitrate, and drying the pieces so dipped. The potassium nitrate paper is intended to be burnt and the vapor inhaled in cases of asthma.

PART III

CHAPTER XXII

INTRODUCTION

A THOROUGH explanation of the sciences of physics and chemistry is beyond the scope of this work, and for complete information on these two sciences the reader is referred to the several works on these subjects noted in the Preface to this work.

There are, however, some facts connected with these two sciences the knowledge of which is essential to a student of the succeeding chapters of this work, and these essential facts are here given.

Matter is anything that has extension (possesses length, breadth, and thickness) or is appreciable to our senses (can be seen, felt, tasted, or smelled). Thus, water is matter, or anything else on this earth or in the air around us, which we can touch, which our senses tell us exist. All matter is divided into solids, liquids, and gases.

A solid is that form of matter which holds a definite shape-whose molecules do not move among themselves.

A liquid is that form which is mobile-which assumes the shape of the vessel in which it is placed; whose molecules move freely among themselves.

A gas is that form of matter whose molecules tend to separate from one another.

When we call any portion of matter a solid, a liquid, or a gas, we mean that it usually assumes the form which we call it. We know that water, usually a liquid, can be frozen into a solid-ice-or converted by heat into gas-steam. Such is the case with all other matter. Each kind of matter can be changed from the form it usually assumes-be it solid, liquid, or gas-into the other two forms, although sometimes the conversion is very difficult.

Thus, we formerly talked of "permanent gases," by which was meant such gases-air, for instance that could not be converted into the forms of liquid or solid; but lately not only have the so-called "permanent gases "been turned into liquids, but into solids as well.

The word "molecule," used above, is one of the classes into which we group matter, according as we can divide it or break it up. A piece of coal can be taken and broken up into small pieces. These small pieces can be finely powdered, and by certain means we can divide it still more minutely. According to how far this division is carried on we group matter into masses, molecules, and atoms.

A mass is any particle of matter appreciable to our senses. Thus, a big lump of coal or the finest particle of its powder are alike masses. A molecule is the smallest particle of matter than can exist in a free state.

Thus, if we take a dye, dissolve it in water, and keep on diluting the solution, the color grows fainter and fainter until finally we reach

« PreviousContinue »