A%ane'i9i5arm'}  The  Rapid  Determination  of  Heroin.  249 
The  following  method  was  used  and  found,  in  the  absence  of 
morphine  or  any  other  interfering  substance,  to  be  sufficiently  ac- 
curate and  to  possess  the  additional  advantage  of  being  rapid. 
After  the  presence  of  heroin  and  absence  of  morphine  or  other 
interfering  substances  are  ascertained,  a  weighed  amount  of  the 
powder  is  taken  sufficient  to  contain  from  1/50  to  1/20  grain  of 
heroin.  This  can  be  roughly  determined  by  the  qualitative  reactions. 
It  is  placed  in  a  Nessler  tube,  and  1  Cc.  of  a  one  per  cent,  solution 
of  sulphuric  acid  is  added,  and  then  3  Cc.  of  a  solution  consisting 
of  600  Cc.  of  commercial  sulphuric  acid,  300  Cc.  of  water,  and 
25  Cc.  of  a  40  per  cent,  formaldehyde  solution.  This  reagent  will 
produce  a  coloration,  varying  from  a  yellowish  straw  for  1/150 
grain  to  a  deep  cherry  red  for  1/5  grain  of  heroin,  depending  upon 
the  length  of  time  the  reaction  is  allowed  to  proceed  and  the  amount 
of  heroin  present. 
A  series  of  standard  tubes  are  prepared,  containing  1/50,  1/40, 
1/30,  1/20,  and  1/15  grain  of  heroin  respectively  (or  any  other 
suitable  quantity  from  1/150  grain  to  1/5  grain),  and  each  of  which 
is  treated  with  the  reagent  in  the  same  manner  and  at  the  same  time 
as  the  sample.  The  reaction  is  allowed  to  proceed  for  10  or  15 
minutes  in  all  the  tubes,  when  the  coloration  in  the  tube  containing 
the  sample  is  compared  with  the  colorations  in  the  standard  tubes. 
The  standard  tube  which  has  the  same  intensity  of  color  as  the 
sample  contains  the  same  amount  of  heroin,  and  from  this  figure 
we  compute  the  total  amount  of  heroin  in  the  powder  under  exami- 
nation. 
If,  however,  a  mixture  of  cocaine  and  heroin  is  submitted,  we 
determine  the  heroin  and  cocaine  as  follows : 
The  substance  is  extracted  in  the  regular  manner  by  the  im- 
miscible solvents,  and  the  residue  of  heroin  and  cocaine  is  weighed, 
and  dissolved  in  a  known  amount  of  1  per  cent,  sulphuric  acid, 
so  that  1  Cc.  of  the  solution  will  contain  between  1/100  and  1/20 
of  a  grain  of  heroin.  One  Cc.  of  this  solution  is  put  into  a  Nessler 
tube  and  treated  with  3  Cc.  of  formaldehyde  sulphuric  acid  solution. 
The  color  produced  is  compared  and  measured  as  described.  The 
standard  tube  containing  the  same  intensity  of  color  is  used  as  the 
basis  for  computing  the  amount  of  heroin  in  the  weighed  residue, 
and  the  difference  between  the  heroin  and  weight  of  residue  ob- 
tained by  the  immiscible  solvent  represents  the  cocaine. 
The  following  table  illustrates  the  sensitiveness  and  the  limita- 
