PHARMACEUTICAL  NOTICES. 
117 
which  is  doubtless  the  laetucone  of  Lenoir.  These  are  readily 
separated  from  each  other  by  boiling  in  alcohol ;  which,  dissolv- 
ing the  laetucone,  leaves  the  caoutchouc-like  substance  behind. 
This  is  extremely  tenacious  and  ductile,  susceptible  of  being 
drawn  out  into  very  fine  and  long  threads,  like  masticin ;  but  on 
being  heated,  it  successively  melts,  bubbles  up,  sends  forth  a 
white  smoke  smelling  exceedingly  like  burnt  caoutchouc,  and 
loses  its  characteristic  tenacity. 
The  hot  alcoholic  solution  of  the  laetucone  lets  most  of  it 
fall  in  white  flocculi  on  cooling,  and  the  rest  is  obtained  by 
slow  evaporation.  The  best  English  lactucarium  purified  by  this 
process  lost  about  one-fourth  of  its  weight,  became  easily  reduced 
to  an  impalpable  powder,  and  appeared  to  be  of  a  more  decidedly 
bitter  taste,  doubtless  from  its  particles  having  become  divested 
of  their  tough  wrapper  of  caoutchoucoid,  if  we  may  venture  on 
the  coinage  of  a  name  for  this  somewhat  peculiar  substance. 
There  is  some  difficulty  in  obtaining  the  chloroformic  liquor, 
after  maceration,  entirely  clear  from  particles  of  impalpable 
lactucarium  floating  in  it,  and  even  passing  with  it  through  the 
filter :  but  this  may  be  obviated  by  using  the  process  of  dis- 
placement, with  a  closed  percolator  to  prevent  loss  by  evapora- 
tion ;  and  the  chloroform  may  afterwards  be  recovered  by  care- 
ful distillation.  I  have  tried  ether,  instead  of  chloroform, 
hoping  to  substitute  a  cheap  solvent  for  an  expensive  one ;  but 
ether  will  not  answer  the  purpose. 
The  English  lactucarium  appears  to  be  considerably  less 
loaded  with  these  insoluble  matters  than  the  German.  While 
the  English  lost  about  one-fourth  of  its  weight  by  the  above 
treatment,  the  sample  of  the  German  article  lost  about  one  half ; 
more  than  thirty  per  cent,  being  the  pure  caoutchouc-like 
matter,  and  about  ten  per  cent,  being  the  laetucone ;  both  of 
them  well-marked  substances,  but  probably  as  devoid  of  the 
medicinal  virtue  of  the  lactucarium,  as  narcotine  is  of  that  of 
opium. 
Philadelphia,  2nd  mo.  12th,  1858. 
