ON  THE  CULTIVATION  OF  JALAP. 
353 
Let  us  now  consider  what  is  the  climate,  and  what  the  soil,  of 
the  region  in  which  the  jalap-plant  (Exogonium  Purga,  Benth.) 
naturally  thrives, — and  what  the  method  actually  pursued  for 
collecting  and  preparing  the  drug  for  the  market.  On  these 
subjects,  the  most  graphic  information  that  I  have  met  with  is 
contained  in  a  letter  addressed  by  Dr.  Schiede,  a  German  travel- 
ler and  botanist,  to  Dr.  D.  F.  L.  von  Schlechtendal ;  it  bears 
date  Mexico,  26  October,  1829,  and  was  published  in  the  periodi- 
cal called  Linncea  the  following  year.  Of  this  letter,  the  follow- 
ing is  a  translation  : 
"  Before  I  leave  Chiconquiaco*  I  must  communicate  to  you 
the  most  interesting  facts  which  I  have  observed  on  the  occur- 
rence of  Convolvulus  Jalapa,  as  well  as  what  I  have  learnt  re- 
specting the  collection  of  the  root  and  its  preparation  for  the 
market.  In  my  last  collections  from  Jalapa,  I  sent  you  a  large 
number  of  flowering  specimens,  and  added  a  short  description  of 
the  plant,  so  that  this  latter  I  may  here  omit. 
"  The  herbaceous  plant  whose  tuberous  root  furnishes  the  al- 
most indispensable  medicine  called  Jalap,  does  not  grow  in  the 
immediate  vicinity  of  Jalapa,  but  several  thousand  feet  higher, 
on  the  eastern  slopes  of  the  Mexican  Andes,  especially  about 
Chiconquiaco  and  the  neighboring  villages,  and  also,  as  I  hear, 
about  San  Salvador,  on  the  eastern  slope  of  the  Cofre  de  Perote. 
The  mean  altitude  at  which  the  plant  occurs  may  be  stated  as 
about  6000  feet.  In  this  region  it  rains  almost  the  whole  year 
through.  During  summer,  fine  clear  mornings  are  commonly 
succeeded  by  violent  showers  in  the  afternoon  ;  in  winter  indeed 
these  latter  do  not  occur,  but  dense  mists  lie  for  days  and  weeks 
with  but  few  clear  intervals,  on  the  mountains  as  well  as  on  their 
declivities.  The  plant  prefers  shade,  and  is  found  only  in  woods, 
where  it  climbs  over  trees  and  bushes.  The  flowers  appear  in 
August  and  September.  The  root  is  dug  up  during  the  whole 
year,  but  probably  that  is  preferable  which  is  collected  before 
the  young  shoots  appear, — that  is  to  say,  in  March  and  April. 
Note.- — Chiconquiaco  is  a  village  situated  on  the  mountain  known  as 
the  Cofre  de  Perote,  and  in  the  region  called  by  the  Mexicans  Tterra  1 
fria. — D.  H. 
23 
