Am.  Jour.  Pharru. 
25  ov.,  1892. 
Ben  co) '  l-Pseu  do  tro pein  e . 
579 
ing  this  in  the  usual  manner.  But  amongst  the  ferrocyanides  there 
are  some,  like  the  zinc,  nickel  and  cobalt  salts,  which  are  very- 
difficult  to  filter  off,  although  this  presents  no  difficulty  with  mer- 
cury, lead  and  silver  salts.  The  ferricyanides  are,  however,  more 
easily  filterable. 
BENZOYL-PSEUDOTRO  PEINE    (TROPACOCAINE  ?). 
This  base  occurs,  associated  with  cocaine,  cocamine,  cinnamyl- 
cocaine  and  other  bases,  in  Java  coca  leaves,  and  to  some  extent  in 
other  coca  leaves.  It  was  first  recognized  by  Giesel,1  who  separated 
the  base  in  the  form  of  a  hydrobromide,  but  did  not  describe  the 
method  by  which  the  separation  was  effected.  The  chief  points  of 
difference  from  cocaine  were  the  melting  point  of  490  C,  and  the 
comparatively  lesser  solubility  of  the  hydrobromide  and  the  nitrate. 
The  hydrochloride  also  differed  from  that  of  dextro-cocaine  and 
the  base  was,  moreover,  optically  inactive.  Further  investigation 
by  Liebermann2  showed  that  the  composition  of  this  base  was  not 
analogous  to  that  of  cocaine,  and  that  when  split  up  under  the  influ- 
ence of  hydrochloric  acid  it  yielded,  instead  of  ecgonine,  a  base 
isomeric  with  tropine  from  atropine  but,  having  a  much  higher 
melting  point  than  that,  it  was  considered  to  be  identical  with  the 
base  obtained  by  the  similar  splitting  up  of  hyoscine.  The  other 
product  of  the  transformation  being  benzoic  acid,  the  new  coca  base 
was  named  benzoyl-pseudotropeine,  and  Liebermann  succeeded  in 
reproducing  it  synthetically.  At  the  meeting  of  the  British  Medi- 
cal Association,  at  Nottingham,  attention  was  directed  to  this  base 
by  Dr.  A.  P.  Chadbourne,  of  Boston,  U.  S.  A.,  who,  in  a  paper  read 
before  the  Section  of  Pharmacology  and  Therapeutics,3  described 
the  results  of  an  extended  investigation  carried  out  in  the  Pharma- 
cological Institute  of  Berlin  University  with  the  assistance  of  Pro- 
fessor Liebreich  and  Dr.  Langgaard.  He  showed  that  in  many 
respects  the  physiological  action  of  this  base  differs  from  that  of 
cocaine.  It  is  a  powerful  local  anaesthetic ;  but  in  the  eye  does  not 
cause  the  ischaemia  characteristic  of  cocaine,  or  the  marked  irritation 
and  hyperemia  produced  by  the  group  of  substances  which 
Liebreich  has  termed  ansesthetica  dolorosa.    It  was  found  to  be 
1  Pharm.  Zeitung,  July  4,  1891. 
2  Berichte,  xxiv,  2336  j  Jlmer.  Jour.  Phar.,  1892,  44- 
■  British  Medical  Journal,  August  20,  1892,  p.  402. 
