200 
a-  and  fi-Eucaine. 
f  Am.  Jour.  Pharm. 
X       April,  1902. 
very  small  drop  of  a  solution  of  potassium  permanganate  is  added. 
If  the  solution  is  strong  enough  for  a  precipitate  to  appear  at  once 
the  change  can  be  observed  on  the  precipitate,  but  it  is  preferable  to 
watch  the  change  of  color  of  the  solution  itself.  With  either  of  the 
eucaines  the  color  almost  immediately  begins  to  change  to  brownr 
while  with  pure  cocaine  the  original  color  holds  generally  for  fully 
half  an  hour,  but  also  eventually  changes  to  brown.  The  cocaine 
precipitate  examined  under  the  microscope  is  a  beautiful  violet-red 
which  also  in  time  turns  to  brown.  This  is  true  of  the  eucaine  pre- 
cipitates at  first,  but  they  rapidly  change  to  brown.  Excess  of  per- 
manganate should  be  avoided. 
Cocaine  hydrochloride  in  solution,  in  either  water  or  alcohol, 
polarizes  light  strongly  to  the  left.  Antrich1  states  that  this  is  the 
best  test  for  the  purity  of  the  salt.  According  to  this  authority  for 
aqueous  solution  Sd=  — 52-2  and  for  solution  in  alcohol  of  09355 
sp.  gr.,  Sd=  — 68-o6.  A  solution  of  the  hydrochlorides  of  cither  a- 
or  ^9-eucaine  does  not  polarize  light. 
Cocaine  when  used  in  the  eye  almost  always  causes  mydriasis, 
^9-Eucaine  does  not  dilate  the  pupil. 
REACTIONS   CHARACTERISTIC  Or    ^-EUCAINE  HYDROCHLORIDE. 
The  chief  characteristic  property  of  ^-eucaine  hydrochloride  is 
its  comparative  insolubility  in  water  and  alcohol,  and  it  is  readily 
distinguished  from  cocaine  by  this  property.  A  small  test  sample 
of  cocaine  hydrochloride,  if  moistened  with  its  own  volume  of  alco- 
hol or  water,  dissolves  at  once,  while  /3-eucaine  hydrochloride  is  little 
affected.  In  making  the  test,  however,  where  weighed  quantities 
are  not  used,  it  should  be  remembered  that  even  ^-eucaine  is  soluble 
to  the  extent  of  11  per  cent,  in  alcohol,  and  a  too  large  amount  of 
the  solvent  should  not  be  used.  Just  enough  to  moisten  is  all  that  is 
necessary  to  dissolve  cocaine  or  a  eucaine  hydrochloride. 
No  chemical  reactions  of  a  positive  character  have  been  found 
characteristic  of  ,9-eucaine,  but  the  results  with  permanganate,  mer- 
curous  chloride,  platinic  chloride,  and  polarized  light,  will  identify 
cocaine,  while  the  tests  with  potassium  iodide,  potassium  chromate 
and  ammonia  will  distinguish  it  from  a-eucaine.  These  with  the 
other  reactions  noted  will  serve  to  separate  it  from  other  alkaloids. 
( To  be  concluded. ) 
1  Ber.  d.  chem.  Ges.y  20,  310. 
