466 
Alkaloids  of  Coca  Leaves. 
Am.  Jour.  Pharm. 
Oct.,  1885. 
The  writer  has  examined  leaves  which  yielded  no  more  than  0*15  per 
cent.,  and  of  this  scarcely  any  was  capable  of  forming  crystal lizable 
salts.  Freshly  imported  leaves  of  a  recent  crop  contain  generally  0*65 
to  0*8  per  cent,  of  extractible  alkaloid,  but  of  this  not  more  than  one- 
half  generally  consists  of  crystallizable  alkaloid.  In  manufacturing 
operations  the  yield  of  alkaloid  is  much  below  what  assays  show  to  be 
present.  It  is  doubtful  indeed  whether  any  method  of  assay  yet  devised 
extracts  nearly  all  the  alkaloid.  A  good  sample  of  coca  leaves  yields 
a  tincture  which  when  titrated  with  Mayer's  reagent  gives  an  apparent 
alkaloidal  strength  much  higher  than  the  assay  indicates,  but  it  is  alto- 
gether possible  that  the  precipitate  consists  in  part  of  compounds  not 
alkaloidal. 
The  assay  process  adopted  by  the  writer  has  been  recently  des(;ribed 
in  detail  ;^  it  consists  in  treating  the  leaves,  in  fine  powder,  with  about 
eight  times  their  weight  of  a  mixture  of  stronger  ether  95  volumes, 
spirit  of  ammonia  5  volumes,  and  washing  out  the  alkaloid  after  24 
hours'  maceration  from  an  aliquot  portion  of  the  solution,  first  into 
acidulated  water,  then  from  alkaline  solution  into  ether,  evaporating 
and  weighing.  Some  assays  have  been  reported  from  Bolivia  which 
seem  to  show  that  the  leaves  when  freshly  gathered  contain  a  much 
larger  proportion  of  alkaloid  than  after  transportation  to  this  country. 
This  confirms  the  statement  that  has  been  often  made,  that  in  Peru 
and  Bolivia  coca  leaves  are  believed  to  deteriorate  very  rapidly,  so 
that  when  more  than  six  months  old  they  are  not  considered  fit  for 
use.  It  is  even  stated  that  the  coca  chewers  find  that  the  leaves  when 
they  arrive  at  the  coast,  in  the  usual  mode  of  transportation,  are  less 
active  than  at  the  beginning  of  their  journey.  In  a  climate  as  damp 
as  that  of  the  coca-producing  regions  it  is  probably  next  to  impossible 
to  dry  the  leaves  properly  before  packing,  and  it  is  easy  to  understand 
how  under  these  conditions  they  suffer  even  from  so  short  a  journey. 
Some  packages  of  coca  shipped  from  Lima  apparently  in  good  con- 
dition, at  the  end  of  their  voyage  were  found  by  the  writer  much 
heated — temperature  in  the  centre  of  the  package  110°F. — and  evi- 
dently greatly  deteriorated.  These  leaves  contained  nearly  18  per 
cent,  of  moisture ;  had  they  been  really  dry,  i.  e.,  so  as  to  contain  10 
per  cent,  or  less  of  moisture,  they  would  probably  have  lost  nothing 
in  the  transportation. 
1  "Chicago  Pharmacist,"  September,  1885. 
