689

PoV/DERS.

PART III.

which can be effected by simply beating them in a mortar, andpassing them through a coarser sieve, than is employed in theformer case.

As powders are generally affected by the action of air andlight, all powders should be kept in opaque or green glass bot-tles. The effect of light on the majority of powders is renderedobvious by the labelled sides of clear bottles containing them,which are always turned to the light, becoming encrusted withthe powder changed in its colour, while the other side remainsclear and transparent.

In forming compound powders, it is necessary to sift themixture after it has been well triturated. The following gene-ral rule for the formation of powders is given by the Dublin Col-lege. " Let the substances to be powdered be first dried 1 ; andthen beaten in an iron mortar; then separate the finer powderby shaking it through a hair sieve, and preserve it in closevessels."

PUL'VIS AL'OES COjVJPOS'ITUS. Lond. Compound,Powder of Aloes. 2

" Take of extract of spiked aloes, an ounce and. a half; guaiacgum-resin, an ounce; compound powder of cinnamon, half anounce. Powder the extract of aloes and the guaiac separately ;then mix them with the compound powder of cinnamon."

Pulvis Aloes cum Guaiaco. Dub. Powder of Aloes withGuaiac.

" Take of hepatic aliies, an ounce and a half; guaic gum-resin, an ounce; aromatic powder, half an ounce. Rub thealoes and the guaiac separately to powder; then mix themwith the aromatic powder."

Both the active substances in these powders are ill adaptedfor this form of preparation; and the addition of the aromatic

1 Mr. Battley, * respectable druggist in London, has proposed the following methodof drying narcotic plants for powders.

Previous to the process of drying the leaves of plants, the same rules must be carefullyobserved in reviving them which were recommended previous to their being pressed forextracts.

The leaves being in a high state of preservation, and entirely freed from the stalks,and as much as possible from external moisture, must be laid in thin layers in baskets ofwillow stripped of its bark, in a drying room, from which the light is quite excluded. Theyshould be then exposed to a temperature of not less than from 130 to 140 deg. of Fah-renheit's thermometer for three or four hours, or until the leaves begin to shrivel. Theyare then to be turned in the same temperature, and the heat kept up for six or eighthours longer, when the operation is generally finished; which is known by the leavescrumbling without much difficulty in the hand. If the process has been in all its partsproperly managed, the result will be, that the leaves retain a beautiful green colour, andalso in a high degree the medical properties of the plant to which they belong.

To preserve them in this desirable state, oil jars, made perfectly clean and dry, arefound to answer best. Place the leaves lightly in the jars, and hermetically seal them.The filled jars ought to be kept in a dry and warm situation.

* Pilula: de Diarabrce, P. L, 1720. Pulvis Aloes cum Guaiaco, P. L. 1787.