Am.  Jour.  Pharm. 
July,  1902. 
Cheap  Drugs. 
315 
England  the  tuber  is  collected  in  autumn  from  cultivated  plants 
after  the  overground  parts  have  died  down,  whereas,  in  Germany, 
the  tubers  are  collected  from  wild  plants  during  the  flowering  period, 
this  being  done  to  distinguish  the  particular  species  yielding  the 
drug.  The  commercial  drug  may  consist,  then,  of  partially  ex- 
hausted summer  tubers,  autumn  tubers,  or  a  mixture  of  both. 
No  doubt,  much  of  the  early  opposition  to  Rhamnus  purshiana  as 
compared  to  Rhamnus  frangula  was  due  to  the  collection  of  the 
former  at  improper  seasons  as  well  as  to  the  product  being  collected 
from  other  species  of  Rhamnus.  It  is  well  known  that  wild-cherry 
bark  varies  according  to  its  position  on  the  tree.  Then,  too,  col- 
lectors are  not  always  able  to  distinguish  the  species  yielding  the 
official  bark.  Stoeder  has  made  the  interesting  observation  that 
the  pomegranate  bark  yielded  by  trees  with  white  flowers  is  pre- 
ferred by  the  natives  of  Java;  next  in  value  is  the  bark  of  the  trees 
with  red  flowers,  which  are  most  common  in  Java  and  Europe ;  lastly, 
there  is  the  variety  with  black  flowers  producing  a  bark  which  is  still 
less  valuable. 
The  age  of  the  plant  influences  the  nature  of  its  products  in  some 
instances  as  in  the  case  of  coca,  there  being  a  slight  increase  in  the 
amount  of  alkaloids  produced  in  the  leaves  of  the  plant  up  to  the 
age  of  about  ten  years ;  after  twenty  years  there  is  a  diminution  in 
alkaloids,  although  the  yield  is  fair  in  plants  thirty  to  forty  years  old. 
The  position  of  leaves,  as  well  as  age,  in  influencing  the  nature  and 
amount  of  active  constituents,  offers  a  most  fertile  field  for  investiga- 
tion. In  the  case  of  eucalyptus,  the  product  of  a  tropical  tree,  the 
Pharmacopoeia  specifies  the  leaves  produced  on  older  parts  of  the 
plant.  In  herbs  it  directs  in  a  number  of  cases  that  the  leaves  and 
flowering  tops  be  used.  It  is  likely  that  there  is  a  difference  in  the 
constituents  of  the  leaves  found  on  different  parts  of  the  same  plant : 
for  instance,  in  sumach,  the  upper  leaves  contain  a  larger  proportion 
of  tannin  in  June  than  the  lower  leaves,  and  as  the  season  advances 
the  decrease  in  tannin  in  the  upper  leaves  is  also  much  less  than  in 
the  lower  leaves.  It  is  not  unlikely  that  in  this  climate  the  older 
leaves  of  herbs,  which  are  more  or  less  withered  and  imperfect,  are 
like  autumn  leaves  deficient  in  medicinal  activity. 
The  influence  of  the  weather  in  affecting  the  quality  of  drugs  is 
seen  in  certain  instances.  Bad  weather  at  the  time  of  harvesting  of 
fennel  will  produce  a  drug  having  the  appearance  of  an  exhausted 
