538  Effect  of  Phosphatic  Manures.  {A^tJo°ber.SrilJ- 
had  been  growing  in  the  neighborhood  of  a  manure  heap,  afforded 
as  much  as  22  per  cent,  of  resin,  which  may  be  considered  the 
largest  yield  on  record. 
The  question  of  manuring  is  one  of  great  importance  in  cultivat- 
ing drugs  for  the  purpose  of  increasing  their  active  principles.  It 
has  been  proved  over  and  over  again  in  cinchona  culture  that  nitro- 
genous and  phosphatic  manures  increase  the  amount  of  alkaloids  in 
the  bark ;  on  the  same  principle  potash  is  good  for  tobacco  crops, 
and  magnesia  and  lime  cause  a  development  of  sugar  in  the  sugar 
•cane.  There  is  no  doubt  that  better  results  would  be  obtained  in 
growing  medicinal  plants  if  attention  were  directed  to  a  proper  sys- 
tem of  applying  suitable  fertilizing  agents  to  the  crops. 
With  regard  to  the  Nilgiris,  it  is  known  that  there  is  a  deficiency 
of  lime  and  phosphoric  acid  in  the  soil,  and  an  addition  of  these 
two  ingredients  has  always  proved  beneficial  to  the  local  tea,  coffee 
and  cinchona  estates. 
For  the  purpose  of  observing  the  action  of  these  substances  on 
the  growth  of  jalap  tubers,  and  the  effect  they  would  have  of 
increasing  the  active  principle,  an  experiment  was  made  in  which 
some  powdered  mineral  phosphate  and  superphosphate  were  em- 
ployed. Into  one  box  was  placed  some  ordinary  soil  of  poor 
quality ;  in  the  second  the  soil  was  mixed  with  some  mineral  phos- 
phate in  the  proportion  of  16  cwt.  an  acre,  and  in  the  third  the 
soil  was  mixed  with  superphosphate  in  the  same  proportion.  In 
each  of  these  boxes  was  planted  a  small  jalap  tuber,  and  the  boxes 
were  left  undisturbed  for  nine  months.  The  plant  that  grew  from 
the  tuber  in  the  third  box  was  much  taller  than  that  in  the  second, 
and  the  plant  in  the  second  was  finer  than  that  in  the  first.  The 
subterranean  portion  of  the  plants  corresponded  with  the  aerial 
growth,  for  when  they  were  taken  up  the  tubers  were  found  to  have 
developed  remarkably  in  the  manured  soil. 
The  respective  weights  were  as  follows: 
Per  Cent. 
Fresh.  Dry.  of  Water. 
No.  i,  Uumanured  32  7-62  76*2 
"    2,  Phosphate  85  22*44  74'2 
"3,  .   228  54'20  76-2 
The  percentage  of  resin  was  then  estimated  in  the  dry  powder 
with  the  following  results ;  the  amount  of  ash  was  also  taken  in  each 
sample : 
