354 
INVESTIGATION  OF  POISONOUS  ALKALOIDS. 
reacts,  even  when  considerably  boiled,  with  the  metallic  copper. 
If  sulphuretted  hydrogen  is  passed  through  muriatic  acid,  me- 
tallic copper  will  assume  in  the  liquid  a  brown  color,  which  dis- 
appears on  boiling,  leaving  the  copper  bright  ;  but  long  con- 
tinued boiling  will  not  remove  the  bluish  black  deposit  in  the 
above  solution  of  ultramarine,  and  after  the  boiling  has  ceased, 
no  gas  bubbles  will  rise  from  the  blackened  copper.  Copper, 
with  a  precipitate  of  arsenic  deposited  upon  its  surface,  becomes 
positive  electric,  and  dissolves  now  freely  in  the  warm  muriatic 
acid  with  the  evolution  of  hydrogen,  and  may  thereby  be  readily 
distinguished  from  the  copper  blackened  by  sulphur.  Indeed, 
I  have  thereby  discovered,  and  afterwards  proved  by  other  re- 
agents, the  presence  of  arsenic  in  samples  of  ultramarine.  The 
latter  being  prepared  by  calcination  of  Glauber's  salt,  charcoal 
and  clay,  the  source  of  arsenic  is  evidently  the  sulphuric  acid  ; 
and  though  its  proportion  may  be  very  minute,  it  must  not  be 
overlooked  in  forensic  analysis.  It  must  be  remarked,  how- 
ever, that  but  little  of  the  arsenic  is  dissolved  by  the  hydro- 
chloric acid,  the  greater  portion  remaining  with  the  insoluble 
residue  as  sulphide  of  arsenic. 
Of  what  nature  the  sulphur  compound  in  ultramarine  and 
in  sulphuret  of  calcium  may  be,  which  is  not  decomposed  by 
boiling  muriatic  acid,  but  produces  the  stated  peculiar  reaction 
with  copper,  cannot  be  decided  yet :  it  is,  however,  decomposed 
by  chlorate  of  potassa. — N.  Jahrb.  d.  Ph.  xvi.  135—143. 
J.  M.  M. 
PROCESS  FOR  THE  EXTRACTION  AND  INVESTIGATION  OF 
POISONOUS  ALKALOIDS. 
By  MM.  V.  Uslar  and  J.  Erdmann. 
Many  difficulties  attend  the  extraction  of  an  alkaloid  when, 
as  in  medico-chemical  researches,  it  is  associated  with  other  or- 
ganic matters.  The  following  is  a  method  recommended  both  by 
its  simplicity  and  its  generality.  It  is  founded  on  the  following 
facts : — 
1.  Free  vegetable  alkaloids  are  soluble  in  amylic  alcohol, 
especially  by  aid  of  heat. 
