582 
Senna  Pods. 
Am.  Jour.  Pharm. 
Xov.,  1889. 
The  pod  or  legume  consists  of  the  two  valves  of  the  carpellary 
leaf,  bearing  about  half  a  dozen  seeds  attached  by  a  capillary  funicu- 
lus to  the  marginal  placentas ;  each  valve  consists  of  three  layers,  the 
outer,  epidermis,  pierced  with  stomata  and  easily  pervious  to  water ; 
next,  a  central  mass  of  parenchyma  traversed  by  the  "  veins ; M  it  is 
in  this  layer  that  the  cathartin  is  stored  ;  lastly,  a  fibrous  tissue  devoid 
of  active  principle. 
The  advantages  claimed  by  Dr.  Macfarlane  in  the  use  of  the  pods 
over  the  leaves  are  the  absence  of  nauseous  taste  and  of  tendency  to 
cause  griping  pains,  both  of  which  are  associated  with  the  use  of  the 
leaves.  It  was  shown  in  a  paper  printed  in  the  Pharmaceutical 
Journal,  March  18,  1876,  by  C.  L.  Diehl,  that  senna  leaves,  when 
previously  treated  with  alcohol  and  then  dried,  will  give  preparations 
which,  while  possessing  the  purgative  qualities,  are  tasteless  and  do 
not  gripe. 
The  treatment  with  alcohol  had  removed  the  resinous  and  odorous 
principles  to  which  the  griping  and  nauseous  taste  are  due,  leaving 
the  cathartin  unchanged,  it  being  insoluble  in  alcohol. 
The  pods  being  richer  in  cathartin,  and  not  containing  either  resin 
or  oil,  render  them  especially  well  adapted  for  use  as  an  efficient 
aperient,  and  one  not  too  rapid  in  action. 
Cold  water  readily  dissolves  out  the  cathartin  from  the  pod,  which 
it  will  not  do  from  the  leaf,  owing  to  the  impervious  nature  of  its 
epidermis.  Accordingly  for  the  preparation  of  a  fluid  extract,  cold 
water  will  be  found  the  best  menstruum.  Two  macerations  of  the 
carefully  picked  over  pods,  which  should  also  be  torn  in  pieces,  will 
be  found  to  practically  exhaust  them.  The  first  maceration  should 
be  for  twenty-four  hours,  for  the  second  twelve  is  sufficient.  For 
one  pound  of  pods,  six  pints  of  cold  distilled  water  for  the  first  and 
about  three  pints  for  the  second  maceration,  is  a  sufficient  quantity  to 
use,  the  liquors  when  strained  off  to  be  evaporated  to  thirteen  fluid- 
ounces  and  the  usual  four  ounces  (25  per  cent.)  of  spirit  added,  and 
after  standing  a  few  hours  to  be  filtered,  and,  if  necessary,  made 
up  to  sixteen  fluidounces  with  distilled  water. 
This  makes  an  almost  black  looking  liquid  of  specific  gravity 
1040  (average),  perfectly  tasteless,  and  of  which  the  adult  dose  is 
one-half  to  two  fluidrachms,  the  smaller  dose  seldom  failing  to  pro- 
duce purgation. — Phar.  Jour,  and  Trans.,  October  12,  1889, 
p.  281. 
