Fenner's Complete Formulary - Southwest School of Botanical ...

the percolation, when begun, should be conducted rapidly, and
continued to the end with the same menstruum.
2. Gums and gum-resins which agglutinate or mass together when the
menstruum is added. These should be mixed with an equal bulk of sand,
sawdust, or rice chaff, and not packed, but placed loosely, in the
percolator, and the percolation conducted in the usual manner.
3. Bulky drugs, like arnica, buchu, chamomile, etc. Although these
drugs are not difficult to percolate, they absorb so much menstruum
that the expense of making their preparations is considerably increased.
These should be packed as firmly as possible, and held down in the
percolator with a weight during the process of percolation.
Economy in Percolating and Filtering.
Much loss of Alcohol occurs by evaporation when the ordinary
percolator or filtering funnel are left uncovered during percolation or
filtration. To remedy this difficulty a simple apparatus may be
constructed by any druggist who will take the trouble. It is shown in use
in the following cut:
A, is the wooden cover, large enough to fit the top of a percolator or
funnel; it is bound with a wooden hoop, whose lower edge projects about
half an inch below the under surface of the cover; to the wooden hoop is
tacked a piece of moderately thin-sheet rubber, so that the cover when
completed, is like a drum-head, and, when it is used to cover a
percolator or funnel, will make, by its elasticity, an air-tight covering.
B, is a funnel tube, so bent as to prevent evaporation or access of air.
Through it, fresh menstruum or other liquid may be introduced into the
percolator or funnel. A glass or metal tube answers the same purpose,
Fenner’s Complete Formulary - Part I-II - MISCELLANEOUS FORMULA - Page 44
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