From what has already been said regarding excipients it will be seen that dexterity in the art of pill-making largely depends upon knowledge of the physical properties of the ingredients and their relations to the excipients. It is the dispenser with one universal excipient who brings pharmacy into disrepute by turning out pills that disgust the customer by the stickiness which comes over them or disappoint the physician through their marble hardness. Mr. Gerrard's remarks in the previous chapter regarding the essentials of a pill are to the point.

General rules are, however, like the general excipient, a failure now and then. Thus it is good to use glycerin of tragacanth as an excipient for water-insoluble chemicals, and this is admirable and true for bismuth subnitrate, cerium oxalate, and many other inorganic chemicals, also for organic compounds such as quinine sulphate; but the rule breaks down with mixtures of certain powders each of which is sparingly soluble in water- for example, camphor and menthol- which when mixed together liquefy, thus overthrowing the rule as to the excipient.

In this chapter ingredients which behave in an abnormal manner and exceptional combinations of ingredients are treated. The side-titles to the paragraphs are given in Latin when specific articles are dealt with, and in English when groups of a kind are the subject of treatment. Dispensers are advised to add examples from their own experience.

Acetanilidum

Is sparingly soluble in water. Reduce to fine powder and mass with glycerin of tragacanth.

Acids

The mineral acids are rarely, if ever, prescribed in pill form in this country, but it sometimes happens that a German prescription of this nature turns up. With the addition of powdered althaea and glycerinated water good plastic masses are obtained, as in the following:

M. Fiant pilulae 100.

Send out such pills in a bottle.

The following is a curious English prescription:

M. Fiant pil. xij.

The procedure is: Rub the powdered extract with the acid for a few seconds, and mass with the smallest possible quantity of rectified spirit and syrup (equal parts). The well-known Easton's syrup pill is another good instance of the use of mineral acids as excipient:

Fiat massa et divide in pilulas viginti.

Mix the solids thoroughly, add the acid, and beat well. The mass is too soft at first, but soon begins to harden, and should be rolled and cut before too late.