* 
ON  THE  CULTIVATION  OF  JALAP.  355 
their  almost  daily  warmth.  Around  Cordova,  the  plant  will  not 
succeed,  the  climate  being  too  warm.  I  would  advise  you  to 
plant  some  of  the  tubers  out  in  the  free  air,  treating  them  like 
Dahlias, — that  is,  to  take  up  the  roots  in  October,  and  plant 
them  again  in  March  or  April.  Although  the  plants  may  not 
flower  or  ripen  seeds,  the  tubers  will  grow  in  size,  and,  what  is 
more  important,  will  multiply  underground  ad  infinitum.  If 
Jalap  roots  have  so  far  failed  in  Europe,  it  is  because  they  have 
been  treated  as  hothouse  plants." 
Having  these  data  regarding  the  climate  and  soil  which  are 
natural  to  the  jalap  plant,  we  must  next  consider  what  regions 
offer  conditions  sufficiently  similar  to  render  the  culture  of  the 
plant  probably  successful.  It  is  plain  from  the  accounts  I  have 
quoted  that  a  humid  climate  having  a  temperature  rising  in  sum- 
mer to.  about  75°  F.,  and  sinking  in  winter  to  the  freezing 
point,  is  that  which  the  plant  naturally  affects  ;  and  this  is  con- 
firmed by  the  fact  that  the  plant  thrives  perfectly  well  in  the 
open  air  during  the  summer  months,  in  gardens  in  the  south  of 
England,  but  that  it  will  not  endure  unprotected  the  severe 
frosts  of  winter.  Whether  the  great  altitude  above  the  sea-level 
at  which  it  occurs  in  Mexico  is  an  indispensable  condition  for 
its  complete  development,  is  a  point  on  which  we  have  no  infor- 
mation. 
[The  author  now  suggests  Cornwall,  Devonshire,  the  Isle  of 
Wight,  Madeira,  and  some  localities  in  India,  as  probably  suita- 
ble for  its  cultivation,  and  then  continues  :] 
It  must  not,  however,  be  supposed  that  no  attempts  to  culti- 
vate jalap  have  been  made,  though  it  may  be  safely  asserted 
that  none  have  resulted  in  obtaining  for  the  market  a  better 
supply  of  the  drug.  In  Mexico,  as  Schiede  relates,  the  Indians 
were  commencing  in  1829  to  cultivate  the  plant  in  their  gardens  ; 
and  I  have  been  informed  by  a  London  druggist  that  some  of  the 
jalap  now  found  in  the  market  is  derived  from  cultivated  plants. 
The  late  Dr.  Royle  states  that  he  sent  plants  obtained  from  the 
Royal  Horticultural  Society  and  from  Dr.  Balfour,  of  Edin- 
burgh, to  the  Himalayas,  where  he  hoped  they  would  soon  be 
