R: Herbal PERCOLATION

Define:
>>
Percolation, or Displacement, is the process whereby a powder
<-ontained in a suitable vessel is deprived of its soluble constituents by
the descent of a solvent through it. The importance of this process
cannot be overestimated, as the progress made in pharmacy in America
during the last half-century is largely due to the study and development
of percolation, and the introduction of preparations which are the direct
outgrowth of the process.
History.—The practice of exhausting wood-ashes of their soluble
constituents bv pouring water upon them after their introduction into a
conical-shaped wooden vessel called a lye-hopper is an ancient one, and
the process is still practised and known as lixiviation. The first attempt
on record to apply the principle to powdered drugs was made by Count
Real, who about the year 1815 invented a press which consisted of a
metallic cylinder with a stop-cock in the bottom and containing a perfo
rated diaphragm for supporting the substance, and with a tight cover at
the top, to which was attached an upright tube, ten or twelve feet high,
having a funnel soldered to its upper extremity : the cylinder was packed
with the coarsely-ground drug, and water poured into the tube. The
pressure of the column of water was so great, however, that the princi
pal difficulty in using the apparatus was in securing tight joints, and
in preventing the incomplete exhaustion of the drug on account of the
too rapid passage of the water through it. M. Robiquet subsequently
made some experiments to determine the power of ether as a solvent in
extracting the fixed oil from the bitter almond : he observed that ether
poured on powdered bitter almond displaced the fixed oil without mixing
materially with it, and he published his observation. It was reserved,
however, for the Boullay brothers, of Paris, in 1833, to apply the ideas
of Real and Robiquet to drugs and medicinal substances in general, and
to them belongs the credit of first demonstrating the value of the pro
cess of percolation in its pharmaceutical applications. The researches of
the Boullays at once attracted the attention of American pharmacists, and
the labors of Duhamel, Procter, Grahame, Squibb, and others during the
last half-century, and the adoption of the process in the Pharmacopoeias
of 1840, 1850, 1860, 1870, and 1880, sufficiently show the character of
the growth in favor of percolation. In Great Britain, France, and
Germany the process is well known and is practised to some extent, but
maceration still holds in these countries the chief place as a means of
extracting the soluble principles of drugs.
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Note this is just the start of a very informative chapter on Percolation.
Ref. P 227

THE PRACTICE OF PHARMACY: A TREATISE ON THE MODES OF MAKING AND DISPENSING OFFICINAL,UNOFFICINAL, AND EXTEMPORANEOUS PREPARATIONS, WITH DESCRIPTIONS OF THEIRPROPERTIES, USES, AND DOSES.INTENDED AS A HAND-BOOK FOR PHARMACISTS AND PHYSICIANS AND A TEXT-BOOK FOR STUDENTSBY JOSEPH P. REMINGTON, Ph.G., (1886)

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