424 
Studies  in  Extraction. 
5  Am.  Jour.  Pharm. 
(      June,  1921. 
tus  was  then  tightly  closed  and  was  allowed  to  macerate  exactly 
48  hours  when  percolation  was  commenced.  The  flow  of  percolate 
was  so  adjusted,6  that  one  gallon  of  percolate  was  obtained  in  about 
one  hour  and  one-half.  The  percolation  was  discontinued  at  5.30 
P.  M.,  and  was  recommenced  at  8  A.  M.  the  following  day.  The 
procedure  followed  in  collecting  the  samples  was  this :  Each  gallon 
of  percolate  was  collected  separately  in  a  clean  bottle  connected  by 
a  rubber  tube  with  the  percolator  to  avoid  contact  with  the  air.  The 
whole  gallon  was  thoroughly  mixed  and  a  portion  was  then  taken 
for  analysis. 
During  the  process  the  temperature  of  the  percolator  varied 
from  230  to  260  C.  Fresh  menstruum  was  added  continually  to  re- 
place that  percolated  out. 
The  specific  gravity  of  the  samples  was  determined  on  a  West- 
phall  balance  standardized  against  water  at  o°  C.  Alcohol  was  de- 
termined in  a  few  samples  by  distillation  of  50  ml.  samples,  dilution 
of  the  distillate  to  100  ml.  and  determination  of  the  alcoholic  content 
from  the  specific  gravity  at  15. 6°  C. 
The  extract  was  determined  by  the  following  procedure :  25  ml. 
of  the  percolate  were  pipetted  off  into  a  weighed  evaporating  dish ; 
the  pipette  was  rinsed  with  10  ml.  of  distilled  water  and  the  rinsings 
were  added  to  the  sample.  This  was  then  evaporated  to  constant 
weight  on  a  water  bath  and  was  then  heated  to  nearly  constant  weight 
in  an  oven  at  1050  C.  The  weight  of  extract  so  obtained  multiplied 
by  four  gave  the  extract  per  100  ml.  Of  course,  volatile  oils  were 
driven  off  and  lost.  Check  determinations  of  this  method  showed  it 
to  be  accurate  within  0.5  per  cent. 
The  data  obtained  by  the  analyses  and  some  of  the  calculations 
are  recorded  in  Table  I. 
TABLE  I,  PART  I. 
Extract. 
Per  100  ml. 
Alcohol 
Time. 
Sample 
.  S.G. 
(E.)      Per  Gallon. 
by  Vol. 
9.25  A.  M. 
1 
1.0448 
22.40  Gm.    848.  Gm. 
3i-65% 
11. 15  " 
2 
1-0415 
21.60  *  817.7 
I. IO  P.  M 
•  3 
1-0355 
20.12  761.6 
2-45  " 
4 
1. 026 1 
18.38  695.8 
32.5 
3-55  " 
5 
1.0157 
14-04  531-5 
8  Cf.  Discussion,  this  Journal,  Vol.  92,  p.  854  (1920). 
