1044 Wisconsin Academy of Sciences, Arts, and Letters. 
does not appear to offer any special advantage either from a 
pharmaceutic or therapeutic standpoint. 
4) In the Pharmacopoeias of 1870, 1880 and 1890,t he drug 
was directed to be extracted in a percolator specially adapted 
to the use of volatile solvents. See Part I under “Apparatus 
used.” With the change in menstruum (ether to alcohol), a 
special form of percolator was no longer necessary, and the 
Pharmacopoeia now directs that an ordinary cylindrical, glass 
percolator be used. 
5) In the earlier editions of the Pharmacopoeia (1850 to 1880 
inclusive), it was directed that percolation be discontinued short 
of the complete exhaustion of the drug, the object evidently 
having been to economize in the use of the relatively expen¬ 
sive solvent, ether. With the reduction in the price of the 
latter, however, the economic factor diminished in importance 
and as a result the Pharmacopoeia of 1890 directed that perco¬ 
lation be allowed to proceed until the drug was exhausted. 
This is also the procedure given in the more recent editions of 
the Pharmacopoeia, in which alcohol has replaced ether as the 
extracting menstruum. 
In this connection, it is desired to point out that, whereas 
percolation, when ether is the menstruum used, should be con¬ 
tinued to complete exhaustion of the drug in order that the 
extraction of the total amount of therapeutically active con¬ 
stituents may be assured, this procedure does not appear to be 
necessary when alcohol is the solvent employed. While this 
statement is not in conformity with the present pharma- 
copceial directions governing the extraction of the drug and is 
not supported by direct experimental evidence, it is thought 
to be justified in view of the difference in the solubility of the 
therapeutically active resins in the above mentioned men¬ 
strua. The indifferent resin is but slightly soluble in ether. 
It will, therefore, be extracted but slowly by this solvent and 
will be present in the percolate even to the last portions. Al¬ 
cohol, on the other hand, dissolves both, the acid and indiffer¬ 
ent resins readily. These substances should therefore be con¬ 
tained in toto in the first portions of the percolate. In this 
case, it would therefore hppear that the continuation of the 
process of extraction to the complete exhaustion of the drug 
