Am.  Jour.  Pharm.) 
Oct.,  1885.  J 
Alkaloids  of  Coca  Leaves. 
469 
fixed  and  volatile  oils.  The  aqueous  solutions  yield  by  spontaneous 
evaporation  acicular  crystals,  which  after  drying  over  sulphuric  acid 
seem  to  be  anhydrous.  Crystals  obtained  from  alcoholic  solutions  are 
certainly  anhydrous.  Their  form  is  that  of  rhombic  plates,  but  the 
crystals  are  generally  very  imperfectly  formed.    (Fig.  2.) 
Fig.  2.— Cocaine  muriate.  Crystals  obtained  by 
spontaneous  evaporation  of  a  drop  of  satu- 
rated aqueous  solution.   X  100  diameters. 
Cocaine  hydrobromate  is  a  salt  less  employed  than  the  hydrochlo- 
rate,  but  deserving  to  be  better  known.  It  crystallizes  readily  from 
:aqueous  solutions  in  slender  transparent  prisms  (Fig.  4),  which  are 
permanent  in  the  air.  They  contain  two  molecules  (8*57  per  cent.)  of 
-water  of  crystallization.  The  purity  of  the  salt  is  at  once  manifest  in 
its  crystalline  appearance,  and  there  is  no  reason  why  it  should  not 
always  be  offered  in  the  form  of  distinct  crystals.  It  contains  of 
course  a  smaller  proportion  of  cocaine  than  the  muriate  (72*2  per 
cent,  in  the  former,  89*25  per  cent,  in  the  latter),  so  that  to  produce 
the  same  elfect  a  larger  quantity  will  be  required. 
Cocaine  citrate  has  been  employed  to  a  limited  extent  in  dentistry, 
but  has  no  points  of  superiority  over  the  muriate.  It  does  not  easily 
assume  the  crystalline  form,  and  owing  to  its  hygroscopic  nature  it  is 
very  troublesome  to  dispense.  It  can  be  formed  into  pellets  for  den- 
tists' use  without  the  addition  of  any  excipient ;  but  by  the  use  of  a 
small  amount  of  excipient  the  hydrochlorate  can  be  made  easily  to 
answer  the  same  purpose. 
