Am.  Jour.  Pliarm.  \ 
April,  188«.  / 
The  Cultivation  of  Coca. 
191 
graph,  mere  passing  references  being  made  to  them  for  the  present. 
I  have  about  concluded  that  the  percentage  of  the  sweet  alkaloids 
varies  inversely  as  the  amount  and  continuousness  of  moisture  that 
the  plant  receives.  Thus,  the  Peruvian,  Ecuadorian,  and  Brazilian 
coca,  which,  as  I  have  stated,  is  much  more  Copiously  and  regularly 
watered  than  the  Bolivian,  is  markedly  inferior^  so  that  Bolivia  regu- 
larly exports  about  one-eighth  of  her  crop  to  those  countries.  I  am 
inclined  to  think  that  the  greater  breadth  and  thinness  of  the  northern 
leaf  may  be  partly  due  to  the  greater  water-supply  and  the  consequent 
greater  degree  of  evaporation.  Again,  the  Indian  always  seeks  the 
coca  grown  at  the  higher  elevations,  where  the  humidity  is  much  less 
and  more  irregular  than  in  the  districts  along  the  rivers.  We  are 
thus  obliged,  for  reasons  to  be  elaborated  in  the  future,  to  regard  these 
alkaloids  as  preserving  a  sort  of  a  balance  of  moisture,  by  which  the 
plant  stores  up  during  the  wet  weather  a  concentrated  supply  of  water, 
which  may  be  very  slowly  yielded  up  during  a  time  of  need. 
Having  thus  chosen  a  high  altitude,  the  next  thing  is  to  select  a 
soil.  A  rivalry  exists  between  a  yellow  clay  and  a  hill-side  soil  rich 
in  vegetable  matter.  My  assays  have  yielded  the  best  results  (as  to 
total  alkaloids)  from  soils  of  the  latter  class,  and  I  am  inclined  to 
think  that  those  who  prefer  the  former  soil  do  so  because  it  yields  a 
somewhat  larger  crop. 
The  ground  for  the  nursery-bed  is  prepared  during  the  latter  part 
of  the  dry  season  by  breaking  it  up  very  thoroughly  to  a  depth  of  a 
foot  or  more.  The  fruits  mature  during  the  early  part  of  the  rainy 
season,  December  and  January.  They  are  red,  and  consist  of  a  fleshy 
outer  portion  and  a  shell-like  inner  portion,  which  encloses  the  single 
seed.  These  people  suppose  that  the  germ  cannot  escape  from  the 
shell  if  planted  in  its  natural  condition,  and  they  have  continued  for 
hundreds  of  years  to  deposit  the  seeds  as  soon  as  gathered  in  a  shaded 
place,  in  layers  an  inch  or  more  deep  and  covered  with  a  thin  layer  of 
decaying  leaves  or  similar  substance.  The  heat  generated  by  the 
decomposition  of  the  fleshy  pericarp  serves  to  induce  germination,  and 
the  embryo  bursts  from  its  bony  covering.  This  growth  unites  them, 
in  from  eight  to  fourteen  days,  into  a  solid  mass,  which  is  broken  up 
into  small  pieces  and  planted  in  furrows  in  the  nursery.  In  this 
process  very  many  of  the  sprouts  are  broken  olf  and  the  plants  de- 
stroyed. Mr.  Lohse  has  adopted  the  plan  of  sowing  the  seeds  broad- 
cast as  soon  as  gathered,  and  covering  with  a  little  earth,  or,  better,  a 
