Bismuth Salts

Subcarbonate and subnitrate are readily massed with a fifth of their weight of glycerin of tragacanth. Cerium Oxalate is treated similarly.

Butyl-chloral Hydras (Croton Chloral).- In conformity with the rule that white substances should be made into white pills, butyl-chloral hydrate should not be massed with such excipients as confection of hips or extract of gentian, which would give a dark-coloured mass. Equal parts of powdered acacia, tragacanth, and syrup make good pills. Glycerin in any form makes a troublesome buttery mass (a result of solution). A pill containing 2 1/2 grains each of butyl-chloral hydrate and quinine sulphate is a good example of self-excipiency. For a dozen mass use 3 drops of rectified spirit, which partly dissolves the butyl-chloral hydrate, making a sticky exci-pient which binds the quinine sulphate into a white plastic mass that divides well into small 5-grain pills. Butyl-chloral hydrate and exalgin liquefy when rubbed together, and should be treated like similar pills of carbolic acid.

Caffeina

This alkaloid and its citrate present no difficulty when prescribed alone (glycerin of tragacanth is the excipient), but, the citrate being a feeble salt (the acid is potentially free), strange things happen in combination. For example:

Fiat pilula. Mitte tales|xxiv.

When this is massed valerianic acid is liberated by citric acid pushing it out from the zinc salt. The best plan is to use instead of caffeine citrate an equivalent amount of the alkaloid-viz., 14 grains- and mass with tragacanth and syrup.

Calcii Chloridum

Pills of this salt do not silver well unless special precautions are taken. Make a mass with Canada balsam. When rolled out and well rounded, coat the pills with tolu and ether, and after five minutes moisten them very slightly with thin mucilage, applied by the finger and thumb, drop them in the silver leaf, and proceed secundum artem. Send the pills out in a well-corked bottle, as they are likely to deliquesce.

Calcii Sulphidum

Fractions of a grain are given at a time, and the pills are usually less than 1 grain in size. Triturate the sulphide with 1/2 grain of sugar of milk for each pill, then add 1/24 grain of powdered tragacanth, and mass with glycerin. This makes an odourless mass; the presence of water in any form, even as in confection of roses or an aqueous extract, decomposes the sulphide with evolution of sulphuretted hydrogen, and the virtue of the pill is thereby more or less destroyed.

Camphor generally gives trouble, and is the rock upon which many candidates for examination are stranded. In the first place powder the camphor finely- it is preferable to use flowers of camphor- by the aid of a little spirit; then, if the pill contains camphor simply, mass with glycerin of tragacanth. This also serves well for such a pill as-

Some dispensers prefer to use an excipient consisting of soap and a little fixed oil for camphor alone, as in the following formulae:

M. Fiant pil. vj.

Large-size Pills.

Fiat massa et divide in pil. vj.

When extract of henbane (or other green extract) is ordered along with camphor, powder the latter with the addition of a little soap instead of spirit. The extract will then make a good plastic mass which retains its consistence for some time. If the extract should make the mass too soft, it may be stiffened with powdered curd soap, or a mixture of the soap with liquorice.

When there is a large proportion of gum resin in the mass, rectified spirit is a good excipient, as in the following:

Fiant pil. xxiv.

Another example:

M. Fiat mas. et div. in pil. xxx.

In this case powder the camphor by aid of a drop or two of water and the zinc sulphate, add the quinine and extract, with a few grains of tragacanth, and make a softish mass with a mixture of 2 parts of simple syrup and 1 part of glycerin.

The phenol table (page 97) shows that camphor liquefies with chloral hydrate and other substances. The following prescription gives considerable difficulty:

Fiat massa et divide in pilulas viij.

The resulting mixture absorbs more than double its weight of powdered liquorice. Soap is inadmissible for such a mass, as the trace of alkali in it splits up the chloral hydrate. A good mass was made by adding 16 grains of powdered liquorice, 4 grains of powdered tragacanth, and 2 drops of water. Beaten well, the mass was soft at first, but turned out all right.