312  Acetic  Acid  in  Extracting  Drugs.    {Am jTu°1°,[,i8wfriu; 
In  assaying  these  largely  evaporated  extracts  before  the  evapora- 
tion and  after,  very  slight  loss  of  alkaloids  was  discovered,  and  it  is 
believed  that  these  are  fairly  safe  in  acid  solution  with  no  greater 
heat  than  a  water-bath. 
This  point  is  in  favor  of  the  acid  menstruum,  since  it  is  the  com- 
mon experience  that  evaporation  with  alcoholic  menstrua  generally 
reduces  the  proportion  of  alkaloids,  changing  them  and  probably 
oxidizing  them  as  is  not  probable  with  acid  salts  and  solutions  of 
most  alkaloids. 
It  was  desirable  to  know  with  a  fair  degree  of  accuracy  how 
much  free  acid  an  acetic  acid  fluid  extract  of  cinchona  with  this 
menstruum  would  contain,  and  in  the  above-described  three  por- 
tions of  fluid  extract  the  proportion  was  found  to  be  ii,  IO-2  and 
10  percent.,  and  where  there  had  been  most  evaporation  there  was 
least  free  acid.  The  lowest  of  these  proportions  is  quite  sufficient 
to  secure  the  stability  and  permanency  of  the  preparations  under 
all  ordinary  conditions.  When  this  fluid  extract  is  mixed  with  three 
or  four  times  its  volume  of  water,  the  mixture  has  the  appearance  of 
coffee  with  milk,  and  in  this  condition  the  taste  of  free  acid  is  very 
slight  and  not  disagreeable,  and  the  conclusion  is  reached  that  in  all 
discovered  ways  it  is  a  better  therapeutic  agent  and  a  more  eligible 
preparation  than  the  officinal  fluid  extract  and  at  far  lower  cost. 
THE  ASSAY  PROCESS  FOR  CINCHONA. 
The  cinchona  should  be  in  fine  powder  for  complete  exhaustion, 
and  the  harder  the  bark  the  finer  the  powder  should  be.  The  U.S.P. 
directs  a  No.  60  powder  for  its  preparations,  but  No.  80  or  finer  for 
its  assay  process.  The  B.P.  directs  No.  60  for  both  preparations 
and  assay.  But  the  results  obtained  here  by  the  use  of  10  per  cent, 
acetic  acid  as  a  menstruum  show  that  complete  exhaustion  is  easily 
obtained  with  a  No.  9  powder  for  the  assay  process. 
The  apparatus  and  management  are,  however,  of  great  importance 
in  obtaining  complete  exhaustion  if  the  residue  is  to  be,  as  it  should 
be,  bitter-free  when  well  chewed.  This  is  so  difficult  and  of  so  much 
importance  that  it  appears  to  be  worth  while  to  offer  a  cut  of  an 
extractor  that  has  been  very  successful  in  the  extraction  of  nux 
vomica  and  now  in  the  still  more  difficult  cinchona,  and  that  is  ex- 
pected to  be  equally  applicable  to  many  other  substances. 
This  simple  apparatus  is  shown  in  operation.    The  flattened  end 
