Pix Liquida

Add a little wax (1 to 5), heat, and mass with wheaten flour or any fibrous powder.

Plumbi Acetas

Mass with glucose and a little compound tragacanth powder.

Potassii Acetas

A good mass is formed by acetate of potash 18 parts, boro-tartrate of potash 3 parts, and water 1 part. Keep in well-corked bottles.

Potassii Bichromas

Treat like permanganate (p. 124).

Potassii Iodidum

Rub the salt in a mortar with a few drops of water into a stiff smooth paste, and mass with a little liquorice powder ; in this way 6 grains may be easily got into a fair-sized pill. Tragacanth and water alone make a good mass. A pill containing this iodide and a considerable quantity of extract of colchicum was ordered, and although carefully dried extract was used, the mass proved to be too soft. As the pills were not required till next day, they were placed under a bell jar (a mortar upside down) with sulphuric acid. This proved a success, and has often been found useful with an otherwise refractory pill.

Potassii Permanganas

Some years ago the proposal to administer this highly oxidising compound in pill form for certain female complaints brought out a number of suggestions as to the manner in which the permanganate should be made into pill. Obviously no substance which is readily oxidised, such as extract of gentian or glycerin of tragacanth amongst common pill-excipients, should be used. The excipient must be a substance which is practically unoxidisable, and such we have in various fats and earths. For example, resin ointment 1 part and permanganate of potash 4 parts make a good mass, but if kept for some time it disintegrates with great difficulty. Mr. Martindale at first used vaseline, then a mixture of vaseline and hard paraffin, but the mass lacked firmness; then he added kaolin, which gave the desired firmness, and from this was evolved kaolin ointment, now a regular stock excipient. Mr. Martindale recommended the pills to be coated with san-darac varnish, but this is questionable advice, for the alcohol penetrates the pill, and is oxidised by a portion of the permanganate.

It is better to give the pills a thin coating with a solution of white wax or hard paraffin in benzene, afterwards finishing off with French chalk.

The following prescriptions have to be treated on the principles laid down in the foregoing:

For No. I. make a mixture of hard paraffin and vaseline, of each 1/2 drachm, and to this add the cinchonine previously rubbed down fine, then add the manganate and oxide of iron, both in fine powder, and stiffen with a little kaolin if necessary. In the case of No. II. rub the extract with 12 grains of fullers' earth, and the permanganate with 6 grains and the same of vaseline; mix the two, and mass with resin ointment.