AN  ESSAY  ON  SENNA. 
199 
of  lead,  the  mixture  well  agitated,  filtered,  the  animal  charcoal 
dried  and  treated  with  boiling  ether.  This,  on  evaporation, 
yielded  an  additional  crop  of  the  same  crystalline  substance.  No 
more  could  be  obtained,  however,  by  a  repetition  of  the  process, 
at  least  not  more  than  an  additional  grain  or  two. 
That  this  neutral  crystalline  substance  is  the  long  sought  for 
"  active  principle  of  Senna,"  the  writer  feels  convinced,  especi- 
ally upon  the  similarly  successful  determination  of  several  ex- 
periments since  made  with  the  drug,  and  the  undoubted  purga- 
tive properties  of  the  new  product. 
On  heating  10  grains  of  the  crystals  in  a  porcelain  crucible, 
they  fused,  took  fire,  and  left  a  mass  of  porous  charcoal,  which 
was  entirely  burnt  upon  a  red  hot  iron  plate.  The  active  princi- 
ple was  blackened  by  sulphuric  acid  very  quickly  by  the  aid  of 
heat.  These  tests  show  it  to  be,  without  dispute,  an  organic 
principle. 
Thinking  it  worthy  of  experiment  to  examine  into  the  medicinal 
powers  of  our  indigenous,  officinal  species  of  cassia,  "  Cassia 
Marilandica,"  which  grows  so  profusely  along  the  sandy  river 
banks  of  our  neighborhood,  the  writer  collected  a  quantity  of  the 
leaflets  directly  after  the  maturity  of  its  showy  yellow  flowers. 
An  extract  was  prepared  by  evaporating  the  infusion,  which 
possessed  in  some  degree  the  taste  of  the  extract  prepared  of  the 
imported  Senna.  This  proved  cathartic  in  doses,  equivalent  to 
3ss.  of  the  leaflets,  notwithstanding  the  assertion  of  some  au- 
thorities, that  this  species  of  cassia  is  entirely  inert.  Upon  ex- 
amination, the  plant  yielded  all  the  coloring  matters  found  in  the 
commercial  varieties,  a  somewhat  similar  resin,  though  decidedly 
less  acrid  and  nauseous,  a  large  amount  of  glucose,  and  the  same 
crystalline  cathartic  principle,  the  yield  of  this,  however,  being 
smaller. 
It  is  noteworthy  that  the  percentage  of  active  principle  thus 
obtained  is  so  exceedingly  small.  The  rather  unscientific  method 
of  its  isolation  may  in  a  great  measure  account  for  this.  Upon 
further  investigation,  and  by  capable  experimenters,  it  will  no 
doubt  be  found  to  exist  in  larger  proportions  in  the  drug,  and 
more  advantageous  methods  for  obtaining  it  will  be  probably 
devised. 
