68 
SENNA. 
The  dried  sulphide  boiled  in  alcohol  yielded  a  resinous,  very 
nauseous  substance  insoluble  in  water,  soluble  in  alcohol  and  in 
ether. 
The  dried  sulphide  boiled  in  ether  gave  a  crop  of  interlaced 
acicular  crystals  of  dirty  white  color,  at  first  tasteless,  afterwards 
persistently  bitter  and  nauseous.  Five  grains  purged  actively 
five  hours  after  taking.  A  second  quantity  of  crystals  was  ob- 
tained from  the  liquid  by  treatment  with  animal  charcoal,  and 
boiling  as  before  in  ether.  He  claims  for  this  substance  the 
position  so  long  usurped  by  the  pretended  senna  Cathartin  of 
Lassaigne  and  Fenuelle,  and  names  it  "  Sennin." 
The  characteristics  of  this  new  "  Sennin"  are  thus  described  : — 
It  is  insoluble  in  water,  cold  or  hot,  insoluble  in  acids,  insoluble 
in  alkalies,  insoluble  in  cold  alcohol ;  soluble,  to  some  extent,  in 
hot  alcohol  and  in  ether,  but  especially  soluble  in  chloroform. 
All  this  being  true,  how  on  earth  could  the  sennin  have  been 
induced  to  leave  its  nidus  by  the  mere  action  of  cold  water  ? 
This  consideration  determined  me  on  repeating  the  experiment, 
but  fortunately  I  was  saved  the  trouble  by  the  announcement  of 
Herr  Kubly,  who  has  carefully  trodden  the  same  path  as  Mr. 
E-au,  but  with  greater  discernment,  that  the  "  dirty-white  inter- 
laced acicular  crystals"  were  in  point  of  fact  neither  more  or 
less  than  sulphur.  It  must,  however,  be  remembered  to  Mr. 
Rau's  credit,  that  he  gave  the  finishing  blow  to  the  pretensions 
of  Lassaigne's  Cathartin,  and  also  proved  the  incorrectness  of 
Martins'  assertion  respecting  chrysophanic  acid — it  exists  in 
senna  in  very  minute  proportion  only. 
My  own  experiments  were  commenced  in  1862,  by  an  exami- 
nation of  the  precipitate  that  so  invariably  collects  at  the  bottom 
of  old  samples  of  Liquor  Sennse.  I  found  it  to  consist  of  phos- 
iphate  and  sulphate  of  lime  combined  with  resinous  acids,  some 
of  which  were  soluble  in  alcohol,  some  in  ether,  some  only  in 
alkaline  solutions.  The  whole  treated  with  liquor  potassse  in 
considerable  excess,  dissolved,  producing  a  rich  brown  color. 
JFrom  the  filtered  solution  hydrochloric  acid  precipitated  the 
Tesins — brown  in  color  when  pulverulent,  black  when  fused  into 
masses.  Eight  grains  of  this  substance  taken  for  a  dose  pro- 
duced no  efi'ect  whatever  on  the  bowels.    As  similar  resinous 
