PHARMACY. 
fibres, and have but a small sap, may be 
dried at once ; if juicy and not aromatic in 
a heat somewhat below 100“ of Fahrenheit ; 
but if aromatic by simply exposing them to 
a current of cold dry air, and frequently 
turning them in it. If very thick and 
strong, they must be split and cut into slices, 
and strung upon threads ; if covered with a 
tough bark they may be peeled and dried 
while fresh. Such as lose their virtues by 
drying are to be kept buried in dry sand. 
It is difficult to lay down general rules for 
collecting stalks and leaves, some of which 
acquire, while others lose their activity by 
age. Aromatics should be collected after 
the flower-buds are formed ; non-aromatics 
if annuals, when in flower, or about to 
flower ; biennials before they shoot ; and 
perennials before they flower, especially 
the woody-fibred. They should be ga- 
thered in dry weather, after the morning 
dew is off, or before it falls in the evening. 
Generally speaking, they should be tied in 
bundles, and hung up in a shady, warm, and 
airy place, or spread upon the floor, and 
frequently turned. If very juicy, they are 
to be laid upon a sieve, and dried by a 
gentle degree of artificial warmth. Sprouts 
are to be collected before the buds open ; 
and stalks to be gathered in autumn. Barks 
are to be collected when the most active 
parts of the vegetable are concentrated in 
them. Spring is preferred for resinous 
barks, and autumn for the others which are 
rather gummy than resinous. Young trees 
afford the best bark for medical pur- 
poses. . 
The same rules apply to the collection ot 
woods ; but they must not be taken from 
very young trees. Among the resinous 
woods, the heaviest, which sink in water, 
are selected. The alburnum is to be re- 
Jcctsd* 
Flowers are collected in clear dry wea- 
tlier, before noon, but after the dew is off; 
either when they are just about to open, or 
immediately after they have opened. Of 
some the petals only are preserved, and the 
colourless claws are even cut away ; of 
others whose calyx is odorous, the whole 
flower is kept. Flowers which are too 
small to be pulled singly, are dried with 
part of the stalk : these are called heads or 
tops. 
Flowers are to be dried nearly as leaves, 
but more quickly, and with more attention. 
As they must not be exposed to the sun, it 
is best done by a slight degree of artificial 
warmth. When tliey loose their colour and 
smell they are unfit for use. 
Seeds and fruits, unless when otherwise 
directed, are to be gathered when ripe, but 
before they fall spontaneously. Some pulpy 
fruits are freed from their core and seeds, 
strung upon thread, and dried artificially. 
They are in , general best preserved in their 
natural coverings, although some, as the co- 
locynth, are peeled, and others, as the ta- 
marind, preserved fresh. Many of these are 
apt to spoil, or become rancid ; and as they 
are then no longer fit for medical use, no 
very large quantity of them should be col- 
lected at a time. 
Tlie proper drying of vegetable sub- 
stances is of the greatest importance. It is 
often directed to be done in the shade, and 
slowly, that the volatile and active particles 
may not be dis.sipated by too great heat ; 
but this is an error, for they always lose in- 
finitely more by slow than by quick drying. 
When, on account of the colour, they cannot 
be exposed to the sun, and the warmth of 
the atmosphere is insufficient, they should be 
dried by an artificial warmth, less than 100“ 
Fahrenheit, and well exposed to a current 
of air. When perfectly dry and friable, they 
have little smell ; but after being kept some 
time, they attract moisture from the air, and 
regain their proper odour. 
The boxes and drawers in which vegeta- 
ble matters are kept, should not impart to 
them any smell or taste ; and more certainly 
to avoid this, they should be lined with 
paper. Such as are volatile, of a delicate 
texture, or subject to suffer from Insects, 
must be kept in well covered glasses. Fruits 
and oily seeds, which are apt to become 
rancid, must be kept in a cool, and dry, 
but by no means in a warm or moist 
place. 
Oily seeds, odorous plants, and those con- 
taining volatile principles, must be collected 
fresh every year. Others, wliose properties 
are more permanent, and not subject to de- 
cay, will keep for several years, Vegetables 
collected in a moist and rainy season are in 
general more watery and apt to spoil. In a 
dry season, on the contrary, they contain 
more oily and resinous particles, and pre- 
serve much better. 
Mechanical Operations. 
These consist of the mode of determining 
the weight or measure of bodies ; their 
division into minute particles ; their sepa- 
rafton of part from part, or of the useful 
