S-ENNA. 
67 
"  adulterating"  Alexandrian  senna  with  the  leaves  of  CynancTium 
Argel.  As  the  latter  are  now  known  to  be  destitute  of  purga- 
tive power,  and  purely  bitter,  it  would  be  interesting  to  ascertain 
the  comparative  potencies  of  pure  senna,  and  of  that  mixed  with 
cynanchum.  Should  it  turn  out  that  the  admixture  really  effects 
an  improvement  of  quality,  we  may  perhaps,  without  great  stretch 
of  charity,  ascribe  the  systematic  admixture  of  the  two  leaves  to 
a  desire  to  improve  the  article.  Cheapen  it,  it  does  not.  It  has 
been  remarked  with  wonder  by  travellers,  that  the  senna  leaves 
are  quite  as  easy  obtainable  as  those  of  the  plant  used  presuma- 
bly for  its  sophistication. 
Senna  was  invariably  exhibited  in  a  watery  vehicle,  and- this 
is  as  it  should  be;  strong  spirit  fails  altogether  to  extract  its 
active  principle,  notwithstanding  Christison's  statement  to  the 
contrary. 
Among  the  more  noteworthy  examinations  of  senna  of  recent 
date  are  those  of  Robert  Rau,  of  Bethlehem,  Pennsylvania,  and 
of  Professor  Dragendorf  and  Herr  Kubly,  of  Dorpat. 
Rau's  results  have  since  been  disproved,  but  as  his  experi- 
ments present  many  points  of  interest  I  will  shortly  enumerate 
them.  The  paper  will  be  found  in  extenso  in  the  American 
Journal  of  Pharmacy/  for  186H.  He  commences  by  asserting  the 
inertness  of  the  resin  extracted  from  senna  by  the  use  of  alcohol, 
and  in  that  is  perfectly  correct. 
The  active  principle  being  supposed  still  to  remain  in  the 
residue  of  the  operation,  the  senna  is  extracted  next  with  cold 
water,  and  to  the  infusion  diacetate  of  lead  is  added  in  excess. 
The  filtrate  from  the  precipitate  thus  formed  is  freed  from  lead 
by  sulphuric  acid,  and  being  then  evaporated,  the  sweet  extract 
was  found  destitute  of  purgative  action.  He  found  the  same 
inertness  in  that  part  of  the  extract  soluble  in  spirit — the  so- 
called  cathartin  of  Lassuigne.  The  yellow  lead  precipitate  was 
next  examined.  When  dried  and  boiled  with  alcohol  it  yielded 
a  substance  of  a  deep  yellow  color  which  was  darkened  bv  alka- 
lies. It  consisted  of  two  resinous  bodies,  chrysoretin,  etc.  The 
residue  suspended  in  water  was  decomposed  with  sulphuretted 
hydrogen,  and  furnished  only  a  tasteless,  gummy  substance  of 
acid  reaction,''  that  seemed  unworthy  of  further  notice. 
