474 
Alkaloids  of  Coca  Leaves. 
{Am.  Jour.  Pharm^ 
Oct.,  1885. 
Caustic  alkalies  precipitate  the  alkaloid  in  crystalline  form  from 
moderately  dilute  solutions ;  from  stronger  ones  in  amorphous  state,  but 
soon  assuming  crystalline  form.  Thus,  in  a  solution  1 :  500  ammonia 
produces  at  once  a  white  precipitate,  which  soon  changes  to  stellate 
groups  of  crystals.  In  a  solution  1 : 1,000  the  crystals  appear  in  a  few 
minutes;  in  a  solution  1:1,500  the  crystals  develop  only  after  some 
time. 
Caustic  soda  and  potash  produce  very  similar  effects,  the  crystals- 
perhaps  forming  more  promptly.  Where  ammonia  is  the  precipitant 
the  crystals  often  arrange  themselves  in  complicated  growths,  tufts  of 
acicular  crystals  springing  from  the  nodes  of  jointed  stems  formed  by 
the  larger  primary  crystals.    (See  Fig.  3,  A.) 
The  carbonates  and  bicarbonates  of  the  alkalies  produce  in  solutions 
of  the  same  strength  precipitates  of  cocaine  alkaloid,  which  are  at  first 
amorphous,  but  which  gradually  take  crystalline  form,  becoming  ulti- 
mately identical  in  appearance  with  the  crystals  produced  by  caustic 
alkalies. 
Fig.  5. — Precipitate  lorined  by  pUitinum  chloride 
in  solution,  1 :  500,  O-  cocaine  hydrochlorate.  X 
100  diameters. 
Platinum  chloride  produces  at  once  in  solutions  1 :400  a  yellow  pre- 
cipitate, consisting  of  plumose  crystals,  mostly  of  stellate  pattern^, 
bearing  thus  a  general  resemblance  to  snow-flakes.  (See  Fig.  5.)  In 
solutions  1:800  the  cryslals  are  more  simple  in  form,  consisting  gen- 
erally of  one  main  crystal,  with  two  or  three  parallel  branches  joined 
at  an  oblique  angle,  and  these  more  or  less  subdivided.    In  solutions- 
