id drachms | are | 1 fluid ounce.
20 fluid ounces... | contained | 1 pint.
8 pints.......... / in \ 1 gallon.

And the signs which distinguish each are as follows:--c. means a
gallon; o a pint; _fl_ [*ounce], a fluid ounce; _fl_ [*drachm], a
fluid drachm; and m, a minim, or drop. Formerly drops used to be
ordered, but as the size of a drop must necessarily vary, minims are
always directed to be employed now for any particular medicine,
although for such medicines as oil of cloves, essence of ginger, &c.,
drops are frequently ordered.

664. Specific Measuring Vessels.

In order that Medicines may be measured Accurately, there are
graduated glass vessels for measuring ounces, drachms, and minims.

665. Approximate Measures.

When proper measures are not at hand, it is necessary to adopt some
other method of determining the quantities required, and therefore the
following table has been drawn up for that purpose:

A tumbler ....... \ / 10 ounces.
A teacup ........ | | 6 "
A wineglass .... | usually | 2 "
A tablespoon..... |- contains -| 4 drachms.
A dessertspoon... | about | 2 "
A teaspoon....... / \ 1 "

These quantities refer to ordinary sized spoons and vessels. Some cups
hold half as much more, and some tablespoons contain six drachms. A
medicine glass, which is graduated so as to show the number of
spoonfuls it contains, should be kept in every family.

[TO-DAY, MAN LIVES IN PLEASURE, WEALTH AND PRIDE.]

666. Process of Making Medicines.

To Powder Substances.--Place the substance in the mortar, and strike
it _gently_ with direct perpendicular blows of the pestle, until it
separates into several pieces, then remove all but a small portion,
which bruise gently at first, and rub the pestle round and round the
mortar, observing that the circles described by the pestle should
gradually decrease in diameter, and then increase again, because by
this means every part of the powder is subjected to the process of
pulverization. In powdering substances, making emulsions, and whenever
using a mortar, the pestle should always travel _from the right to the
left_.

667. Preparation and Assistance.

Some substances require to be prepared in a particular manner before
they can be powdered,