COLD WATER AS A SOLVENT OF DRUGS. 
65 
when mixed with gum, the possibility of which, even out of the 
tissue, was long ago shown by the late Dr. Babington ; secondly, 
that it does not dissipate, but retains the volatile matter ; and, 
leaves behind the starch. Extracts prepared from such infusions 
are more aromatic, more transparent, more soluble, and less liable 
to decomposition. If it is objected that the produce is often con- 
siderably larger when the temperature is employed, I admit it. 
So also is the bulk of scammony when adulterated with flour and 
chalk. But virgin scammony has not a greater superiority over 
the adulterated drug than has the high flavored, soluble, translu- 
cent product of cold maceration over the nauseous, half-soluble, 
hard, opake, starchy extract produced by boiling. 
2. The quantity of cold water is also important. I have been 
led to adopt as a rule of maceration of most substances, twice their 
weight of cold distilled water, adding for each subsequent mace- 
ration as much additional distilled water as the amount of infusion 
previously drained off or expressed. To be thoroughly saturated 
with this small quantity of fluid, the article must be coarsely pow- 
dered, bruised, or cut into small pieces, and repeatedly pressed 
into the fluid with a rammer or with the hand. The specific gra- 
vity of the infusion seldom increases after four or six hours mace- 
ration. In some cases, as roots, leaves, hop, colocynth, &c, strong 
pressure is absolutely necessary to displace the fluid : but in the 
case of barks coarsely powdered, three fifths of the fluid will gene- 
rally drain off without pressure, if time be allowed. If a larger 
quantity of water is employed in maceration, the additional mat- 
ter taken up is chiefly gum and other inactive principles, and the 
medicine is both weakened and impaired by their addition, and is 
liable to become further deteriorated by the longer continuance of 
the heat required to get rid of the superfluous water. 
3. To preserve watery extracts and for the convenience of exhi- 
bition, it has been customary to reduce them to a pilular consist- 
ence. To this there are serious objections. Extractive matter is 
rendered less soluble by the separation of its water, and by the 
heat required for its evaporation ; and the constituents, by being 
brought into too close contact, form new and often very soluble 
compounds, and continue to do so long after the completion of the 
extract, until the properties and value of the medicine are mate- 
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