Am  j'uTv"'i899arm'}     Acetic  Acid  in  Extracting  Drugs.  311 
a  fluid  extract  or  extract  which  on  dilution  splits  up  into  insoluble 
or  difficultly  soluble  cincho-tannates  can  be  a  good  therapeutic 
agent,  or  that  a  preparation  of  the  same  alkaloidal  strength  that 
does  not  so  split  on  dilution  is  not  better. 
The  difference  in  the  cost  of  the  two  menstrua  is  very  great,  the 
alcoholic  menstruum  costing  about  eight  times  as  much  as  the  acid, 
whilst  the  acid  is  much  easier  to  manage  in  the  percolation  and  in 
the  standardizing  process,  since  evaporation  does  not  injure  the  per- 
colates nor  materially  increase  the  cost  by  the  loss. 
The  U.S.P.  standardizes  its  preparations  of  yellow  cinchona  in 
an  indirect  way  by  requiring  that  the  cinchona  from  which  they 
are  made  shall  contain  not  less  than  5  per  cent,  of  total  alkaloids 
and  at  least  2-5  per  cent,  of  quinine,  by  an  assay  process  which  it 
gives,  wherein  a  chloroform  extract  is  weighed  as  total  alkaloids. 
Although  this  is  not  the  only  objection  to  this  assay  process,  it 
secures  a  cinchona  powder  that  should  contain  at  least  5  per  cent, 
of  total  alkaloids,  equal  to  50  grammes  in  I, OOO,  or  25  grammes  in 
500.  The  cinchona  used  for  this  investigation  contained  4*9  per 
cent,  of  total  alkaloids  equal  to  49  grammes  in  1,000,  or  24-5 
grammes  in  500,  or  say  in  500  c.c.  for  facility  of  comparison, 
although  this  500  c.c.  weighs  534  grammes. 
The  U.S.P.  requires  for  its  fluid  extract  that  1,000  c.c.  should  rep- 
resent 1,000  grammes  of  5  per  cent,  cinchona,  or  500  c.c.  containing 
25  grammes  of  alkaloids  from  500  grammes  of  cinchona.  No  one 
of  the  first  percolates  from  either  portion  by  either  menstruum 
comes  up  to  this  officinal  requirement,  but  those  by  the  acid  men- 
struum were  easily  brought  to  it  by  evaporation. 
The  first  500  c.c.  of  the  first  portion  was  evaporated  to  150  c.c, 
and  then  contained  the  proportion  of  25  grammes  of  alkaloids  in  500 
c.c. 
The  first  500  c.c.  of  the  second  portion  was  evaporated  to  238 
c.c,  and  then  contained  the  officinal  proportion  of  25  grammes  of 
alkaloids  in  500  c.c. 
The  first  500  c.c.  of  the  third  portion  was  evaporated  to  298 
c.c,  and  then  contained  the  officinal  proportion  of  25  grammes  of 
alkaloids  in  500  c.c. 
In  the  first  of  these  three  the  loss  in  standardizing  by  evapora- 
tion was  greatest,  and  then  it  amounted  to  about  350  grammes  of  10 
per  cent,  acid,  at  a  cost  of  less  than  4  cents.  But  this  is  a  maximum 
loss  that  in  practice  could  rarely  exceed  half  this  amount. 
