472 
Alkaloids  of  Coca  Leaves. 
(  Am.  Jour.  Phiirm. 
t       Oct.,  1885. 
these  authorities,  ecgonine  has  the  characters  rather  of  an  acid  than  of 
an  alkaloid.  It  is  neutral  in  reaction  and  combines  with  alkalies  to 
form  compounds  which  have  a  faintly  alkaline  reaction  and  are  very- 
soluble  in  water  and  in  alcohol.  It  forms,  however,  double  salts  with 
platinum  and  gold  chlorides,  but,  unlike  those  of  most  alkaloids,  these 
are  readily  soluble  in  water.  By  destructive  distillation  of  the  barium 
compound  of  ecgonine  these  authors  obtained  an  isotropine,  CgH^gj^O, 
which  they  regard  as  raethoxyethyltetrahydropyridine,  ecgonine 
being  methoxyethyltetrahydropyridine-carboxylic  acid,  while  cocaine 
is  methyl  benzo-methoxyetliyl-tetrahydropyridine-car  boxy  late,  an  ex- 
treaiely  plausible  and  lucid  view,  no  doubt,  but  one  which  we  must 
be  content  to  leave  to  the  theorists  to  discuss. 
For  the  identification  of  cocaine  the  organoleptic  properties  of  the 
alkaloid  are  of  the  first  importance.  The  benumbing  effect  upon  the 
tongue  is  unlike  that  of  any  other  substance,  and  is  produced  by  a  very 
minute  quantity  of  the  substance.  The  effect  on  the  mucous  mem- 
brane of  the  eye  is  equally  striking.  One  drop  of  a  4  per  cent,  solu- 
tion will  blanch  the  entire  conjunctiva,  an  effect  which  is  most  strik- 
ingly manifested  on  the  vascular  inner  surface  of  the  lids.  The  anses- 
thetic  effect  is  also  very  noticeable,  even  from  this  small  quantity  of 
the  agent,  and  may  be  fully  developed  by  repeating  the  application 
two  or  three  times  at  intervals  of  two  minutes.  More  or  less  dilata- 
tion of  the  pupil  generally  follows  such  an  application,  but  this  does 
not  appear  to  be  a  constant  effect.  It  is  questioned  by  some,  indeed, 
whether  cocaine  itself  dilates  the  pupil  at  all,  this  effect  being  attrib- 
uted to  hygrine,  or  some  other  accompanying  alkaloid.  I  am  inclined 
to  think  the  effect  is  really  produced  by  cocaine ;  at  least  I  have  not 
succeeded  in  producing  a  salt  which  does  not  exhibit  this  action.  It 
is  certainly  safe  to  say  that  it  is  not  due  to  contamination  with  hygrine, 
which  could  not  be  present  in  the  purified  product. 
Reactions  of  the  various  impurities  liable  to  occur  in  cocaine  have 
not  as  yet  been  sufficiently  studied.  One  curious  one  I  may  mention, 
although  the  explanation  of  it  is  not  yet  found.  This  is  the  develop- 
ment of  an  intense  green  color  by  the  action  of  acids.  When  the  im- 
pure alkaloid  is  treated  with  hydrochloric  acid  to  produce  a  salt  the 
solution  assumes  this  color  as  long  as  the  acid  remains  in  excess.  As 
the  solution  becomes  neutral  the  green  color  fades,  passing  finally  to  a 
brownish  shade,  with  separation  of  a  flocculent  brown  precipitate. 
The  color  suggests  the  idea  that  there  may  be  present  some  chlorophyll 
