146 
TAMPICO  JALAP. 
I  cannot  agree  with  Mr.  Southall  that  both  jalaps  and  their 
respective  resins  are  equally  active,  inasmuch  as  the  resin  in 
Tampico  jalap  is  present  invariably  in  much  smaller  quantity, 
and  is  chemically  different  from  the  true  resin,  of  jalap,  for  it  is 
almost  wholly  soluble  in  ether,  whereas  in  the  other  only  12  per 
cent,  is  dissolved.  This  soluble  portion  is  known  as  jalapic  acid, 
the  insoluble  as  jalapin*  (this  test  affords  a  ready  means  of  dis- 
tinguishing it  from  other  resins,  such  as  guaiacum,  scammony, 
etc.).  Jalapin  is  known  to  the  chemist  as  rhodeoretin,  from  the 
rose-red  color  produced  by  the  action  of  oil  of  vitrol  upon  it, 
and  in  this  reaction  it  is  resembled  by  the  Tampico  resin,  which 
seem  similar  to  that  obtained  from  the  tyomcea  orizabensis,  the 
male,  fusiform,  or  stalky  jalap  of  Guibourt,  whose  resins  from 
this  reaction  was  named  para-rhodeoretin. 
In  odor,  Tampico  jalap  much  resembles  peat  fuel, — peat 
probably  is  used  in  the  drying  of  the  root ;  this  peculiar  smell  is 
very  characteristic;  it  clings  to  it  even  after  it  has  been  dried  in 
a  stove  for  a  considerable  time  ;  in  its  powder  it  is  easily  recog- 
nized, and  even  its  extract  and  resin  retain  the  odor  to  a  slight 
extent ;  but  it  is  not  impossible  that  this  peculiarity  is  due  to  vola- 
tile oil,  as  a  species  of  the  Order  Convolvulacece  yields  a  volatile 
oil  (Rhodoriza). 
Since  making  the  above  experiments,  Mr.  D.  Hanbury  has 
kindly  lent  me  a  paper  entitled,  "  Etude  sur  les  Convolvulacees 
Purgatives,"  by  M.  Ambroise  Andouard.  The  author  states, 
that  Tampico  jalap  is  that  described  by  the  late  M.  Guibourt  as 
"jalap  digite  majeur  ;  analyses  of  some  specimens  indicate  5 
per  cent.,  the  finest  examined  yielded  14  per  cent.  He  fully 
coincides  with  the  opinions  of  Guibourt,  who  says  that  Tampico 
jalap  should  not  be  used  in  the  preparation  of  medicines,  in 
which  jalap  is  a  constituent.  He  (the  author)  does  not  think 
that  this  jalap  should  be  even  classed  with  the  false  jalaps,  such 
as  the  male  or  fusiform  jalap,  or  the  rose  odor  jalap.  The 
resin  he  states  is  purgative,  for  he  himself  has  tested  its  efficacy 
in  a  few  cases ;  his  opinions  are  also  confirmed  by  other  experi- 
*  A  large  proportion  of  jalapin  used  in  this  country  is  supplied  by 
the  German  market. — and  is  nothing  more  than  the  decolorized  resin  of 
either  Tampico  or  the  fusiform  or  male  jalap. 
