TAMPICO  JALAP. 
145 
M.  Guibourt,  twenty-five  years  ago  (Pharm.  Jour.,  vol.  ii., 
336)  recorded  17*65  per  cent,  of  pure  resin,  obtained  from  an 
ordinary  specimen  of  officinal  jalap. 
Having  a  quantity  (56  lbs.)  of  fine  selected  Vera  Cruz  jalap 
in  process  for  the  production  of  resin  when  I  saw  their  letter  in 
the  Journal,  I  determined  to  note  accurately  the  quantity  of 
resin,  free  from  matter  soluble  in  water,  and  in  a  dry  and  pul- 
verulent state  ;  this  was  21J  per  cent.,  or  6J  per  cent,  more 
than^the  maximum  found  by  Mr.  Smith. 
Tampico  jalap  of  the  finest  quality  has  not  given  me  the  for- 
tunate results  of  Mr.  Southall,  for  I  have  never  obtained  more 
than  from  12  to  15  per  cent,  of  resin  ;  nevertheless,  by  selecting 
very  heavy  pieces,  probably  2  or  3  per  cent,  more  might  be  ob- 
tained. 
It  is  quite  possible  to  obtain  33  per  cent,  of  alcoholic  extract- 
ive, even  when  in  a  dry  state ;  but  this  extractive  is  not  wholly 
resin,  for  from  it  there  can  be  easily  separated,  by  means  of 
water,  15  per  cent,  of  saccharine  matter,  and  the  greater  part 
in  the  state  of  grape  sugar.  This,  doubtless,  has  been  Mr. 
Southall's  source  of  error  ;  he  has  evidently  taken  the  alcoholic 
extractive  as  pure  resin,  whereas  the  half  is  nothing  more  than 
sugar.  This  saccharine  matter  exists  in  the  officinal  jalap,  but 
in  a  somewhat  different  proportion ;  four  selected  tubercles 
(very  heavy)  gave  20J  per  cent,  of  pure  dry  resin,  associated 
with  which,  in  the  alcoholic  extractive,  was  9f  per  cent,  of 
sugar.  The  sum  of  these  two  very  nearly  coincides  with  the  30 
per  cent,  of  Mr.  Southall,  as  obtained  by  him  from  the  Vera 
Cruz  variety. 
Thinking  it  likely  that  resina  jalapse  was  to  be  met  with  in  an 
impure  state  in  pharmacy,  four  samples  were  obtained  in  town 
from  first-class  sources  (wholesale  and  retail) ;  these  upon  ex- 
amination proved  that  the  suspicion  was  not  unfounded. 
No  1.  Kesinous.   Translucent  at  edges.  Brittle.  Made  from  Vera  Cruz. 
"  2. 
"  3.        "  "  15  p.  c.  moisture.  " 
4'  {  15  p.*  c.'  sugar,  }  Yer?  °Paclue-  7  P-  c-  moisture.  Tampico. 
This  substitution  of  Tampico  for  Vera  Cruz  jalap  has  doubt- 
less been  caused  by  the  praise  lately  bestowed  upon  the  former. 
10 
