Am.  Jour.  Pharm. 
Jan.,  1890. 
Essence  of  Senna  Pods. 
45 
small  quantity  was  prepared  by  the  evaporation  of  an  infusion  in  the 
way  mentioned  subsequently  by  Mr.  E.  H.  Salmon  in  the  Pharma- 
ceutical Journal  of  October  12,  p.  281  (Am.  Jour.  Phar.,,  Nov., 
p.  581).  This  produced  a  dark  liquid  possessing  scarcely  any  odor  or 
taste,  and  in  no  way  reminded  me  of  its  relation  to  senna  leaves.  I 
should  perhaps  have  agreed  with  Mr.  Salmon  that  it  was  tasteless ; 
but  recently  a  customer  mentioned  that  after  taking  "  tasteless  castor 
oil,"  "  tastless  cod-liver  oil,"  and  "  tasteless  cascara  sagrada,"  he  had 
come  to  the  conclusion  that  a  chemist's  notion  of  the  meaning  of 
"  tasteless  "  was  a  rather  extraordinary  one,  and  differed  widely  from 
that  of  the  public  generally  .  This  was  fairly  efficient  as  an  aperient,  but 
as  it  scarcely  came  up  to  expectations  a  larger  quantity  was  prepared,  to 
meet  a  growing  demand,  in  what  I  regard  as  a  more  rational  manner. 
Mr.  Groves  long  since  determined  that  the  activity  of  senna  leaves 
depended  on  the  presence  of  a  compound  of  cathartic  acid  with  cal- 
cium and  magnesium,  and  that  this  was  injured  by  continued  heating. 
The  active  agent  being  cathartin  in  senna  pods  also,  it  was  evident 
that  to  obtain  the  best  results  extraction  by  pressure,  as  advocated  by 
Mr.  E.  W.  Bell  in  The  Chemist  and  Druggist,  October  6,  p.  609, 
must  be  adopted.  Mr.  BelPs  proposal  is  in  fact  all  that  can  be 
desired,  but  experience  on  several  batches  convinces  me  that  he  does 
not  completely  exhaust  the  leaves,  and  that  the  resultant  fluid  extract 
is  not  a  true  valoid. 
In  other  words,  the  sixteen  ounces  of  finished  essence  does  not,  in 
my  experience,  fully  represent  the  activity  of  the  pound  of  pods 
operated  on.  No  doubt  the  evaporation  method  tends  to  produce  the 
more  nearly  tasteless  preparation,  but  this  will  depend  to  some  extent 
on  whether  the  pods  are  old  and  brown  or  new  and  green.  Nearly  all 
the  supply  at  present  is  fairly  old,  for  the  demand  until  recently  has 
been  exceedingly  small ;  but  that  it  has  grown  considerably  will  be 
evident  from  the  fact  that  the  stock  offering  on  the  London  market, 
October  10,  was  from  fifteen  to  twenty  bales,  whereas  a  fortnight 
later,  as  far  as  could  be  ascertained,  this  had  all  been  bought  up,  and 
there  was  not  a  bale  remaining  in  first  hands.  If  the  pods  have  been 
all  well  preserved  they  contain  a  small  quantity  of  oleo-resin  and 
wax,  which  is  readily  extracted  by  ether  (as  sample  now  shown).  Dr. 
James  wrote  in  1752  :  "  The  fruit  or  follicles  of  the  senna  tree  arc 
less  active  than  the  leaves,"  and  this  is  supported  by  some  opinions  at 
the  present  day;  but  Mr.  Salmon  found  those  he  examined  to  contain 
