536 
Economy  of  Time  in  Percolation.      j A August  i92irm' 
until  750  cc.  of  additional  percolate  were  obtained  in  each  case,  after 
which  the  marc  was  percolated  with  a  fresh  portion  of  the  official 
menstruum,  and  this  weak  percolate  was  put  aside.  The  activity  of 
each  of  the  several  portions  of  percolate  was  then  estimated  by  means 
of  the  biologic  test  on  cats.  The  protocol  (in  brief)  of  an  experiment 
with  each  of  these  two  drugs  follows. 
Strophanthus. — One  hundred  grammes  of  strophanthus  in  No. 
60  powder  were  packed  in  a  percolator,  this  was  percolated  with 
purified  petroleum  benzin  to  remove  fat,  the  defatted  powder  (weigh- 
ing 74  grammes),  was  then  moistened  with  alcohol  and  allowed  to 
stand  two  hours  (instead  of  six  hours),  after  which  it  was  packed 
firmly  in  a  conical  percolator,  alcohol  was  added  and  percolation  was 
allowed  to  proceed  at  once.  The  first  portion  of  250  cc.  of  percolate 
was  obtained  in  a  period  of  about  twenty-one  hours,  and  the  second 
portion  of  750  cc.  in  the  succeeding  period  of  twenty-nine  hours.  Per- 
colation of  the  marc  was  continued  until  250  cc.  of  weak  percolate 
were  obtained. 
The  activity  of  the  several  portions  was  estimated  by  the  method 
described  by  Hatcher  and  Brody.  (Am.  J.  Pharm.,  1910,  Vol.  82,  p. 
360  )  The  activity  of  the  first  portion  of  250  cc.  was  equal  to  about 
17,780  cat  units  (this  amount  would  suffice  to  kill  17,780  kilos  of  cats 
with  intravenous  injection)  ;  the  activity  of  the  second  portion  of 
750  cc.  was  about  equal  to  that  of  the  first  portion  of  250  cc.  (the  total 
activity  of  the  mixed  first  and  second  portions  being  about  35,000  cat 
units)  ;  the  activity  of  the  weak  percolate  was  equal  to  about  926  cat 
units. 
These  results  indicate  that  the  first  portion  of  only  250  cc. 
contained  about  half  of  the  total  of  the  active  principles  of  the  seed, 
that  the  second  portion  of  750  cc.  contained  rather  less  than  half, 
and  that  the  250  cc.  of  weak  percolate  contained  about  2.5  per  cent, 
of  the  total  active  principles. 
Aconite. — One  hundred  grammes  of  powdered  aconite2  were 
moistened  with  menstruum  consisting  of  a  mixture  of  three  volumes 
of  water  and  seven  volumes  of  alcohol,  and  allowed  to  stand  during 
a  period  of  two  hours,  after  which  it  was  packed  in  a  percolator, 
2  The  powder  u.ced  in  this  experiment  was  obtained  from  a  reputable  firm 
and  was  labeled  No.  60  powder,  but  was  evidently  about  No.  80  powder. 
