■Am.  Jour.  Pharm.  \ 
October,  1895.  / 
Acidimetric  Estimation  of  Alkaloids. 
50/ 
Allow  the  mixture  to  separate  completely.  Treat  50  grammes  of 
the  chloroform-ether  mixture  according  to  processes  A  and  B. 
The  great  difficulty  with  a  number  of  the  processes  in  vogue  is 
the  formation  of  obstinate  emulsions.  Of  the  many  assays  made 
by  the  above  process,  not  more  than  one  per  cent,  formed  emulsions. 
The  results  were  obtained  with  nux  vomica  and  ipecac,  as  shown  in 
chart  on  opposite  page. 
From  the  results  embodied  in  this  paper  it  can  safely  be  con- 
cluded that  methyl  orange  cannot  be  numbered  with  the  indicators 
suitable  for  titrating  alkaloids.  It  fails  to  give  satisfactory  results 
with  N100,  N50,  and  stronger  solutions.  Notwithstanding  the  sensi- 
tiveness claimed  for  methyl  orange,  the  writer  believes  that  its  days, 
as  an  ideal  indicator,  are  numbered.  Even  Prof.  Lunge,  the  staunch 
advocate  of  methyl  orange,  has  admitted  that  a  properly  prepared 
solution  of  litmus  is  quite  superior  to  this  indicator  in  inorganic 
titrations. 
A  solution  of  litmus,  prepared  according  to  the  directions  herein 
employed,  is  quite  unsatisfactory  for  delicate  titrations.  The 
method  proposed  by  Reinitzer  promises  to  be  better  suited. 
Of  the  indicators  thus  far  considered,  hematoxylin,  Brazil  wood 
and  cochineal  give  very  promising  results.  Hematoxylin  justly 
claims  first  place,  and  Brazil  wood  second.  Other  indicators  will  be 
considered  in  due  time. 
As  stated  above,  the  prime  object  of  this  investigation  is  to  ascer- 
tain what  indicators  are  best  adapted  to  the  titration  of  alkaloids  ; 
but  in  order  to  determine  how  reliable  the  results  were,  gravimetric 
determinations  necessarily  formed  a  part  of  the  work. 
When  it  is  remembered  that  not  only  do  analytical  methods  contain 
inherent  limitations,  but  also  that  each  operator  possesses  a  positive 
or  a  negative  equation  of  error,  the  reader  will  undoubtedly  concur 
with  the  writer  that  the  results  are  very  satisfactory.  Attention 
must  again  be  called  to  the  fact  that  the  work  was  conducted  under 
precisely  the  same  conditions. 
As  would  naturally  be  expected,  the  amount  of  alkaloid  obtained 
by  process  B  is  smaller  than  that  secured  by  process  A.  A  small 
per  cent,  of  the  alkaloid  may  be  lost  during  the  process  of  extraction  ; 
the  small  amount  of  coloring  matter  possibly  vitiates  the  results, 
or  perhaps  some  non-alkaloidal  substance  increases  the  yield. 
From  the  hundreds  of  assays  made  by  the  author,  he  feels  justified 
in  stating  that  all  of  the  gravimetric  processes  yield  products  con- 
