274 
Saponin  from  Saponaria. 
A.m.  Jour  Pharm. 
May,  1884. 
cool  place,  whereupon  the  sides  of  the  vessel  became  coated  with  a 
copious  yellow  flocculent  deposit  which,  when  freed  from  coloring 
matter  by  treatment  with  a  warm  mixture  of  alcohol  and  ether,  consisted 
of  saponin,  still,  however,  very  impure.  Treatment  with  alcohol  and 
animal  charcoal  still  left  it  contaminated  with  about  3  per  cent,  of 
mineral  matter.  It  was,  therefore  dissolved  in  the  smallest  possible 
quantity  of  water ;  the  cold  solution  was  precipitated  with  saturated 
baryta-wrater ;  the  resulting  barium  saponate,  after  washing  with  baryta- 
water,  was  suspended  in  water  and  decomposed  by  a  current  of  carbonic 
anhydride,  then  heated  to  the  boiling  point,  and  filtered ;  the  filtrate 
evaporated  to  a  syrup  at  a  gentle  heat  was  precipitated  with  alcohol ; 
and  the  still  yellowish  saponin  was  further  purified  with  alcohol  of  90 
per  cent.  The  substance  thus  obtained  still  contained  barium  salts,  to 
remove  which  it  was  dissolved  in  water  and  treated  with  dilute  sul- 
phuric acid,  added  drop  by  drop  ;  and  the  filtered  liquid,  after  concen- 
tration at  a  gentle  heat,  was  precipitated  with  alcohol  and  ether,  these 
operations  being  repeated  a  second  and  a  third  time,  and  the  product 
finally  purified  with  boiling  alcohol  of  90  per  cent,  in  quantity  not 
sufficient  to  dissolve  it  completely.  The  alcoholic  solution  evaporated 
in  a  vacuum  left  perfectly  white  flocks  of  pure  saponin,  which  were 
washed  with  ether  and  dried  over  sulphuric  acid. 
Saponin  thus  prepared  gave,  as  the  mean  result  of  five  analyses  52*65 
per  cent,  carbon  and  7*36  hydrogen,  agreeing  nearly  with  the  for- 
mula C32H54018,  which  requires  52*86  C.  and  7*44  H.  Saponin  from 
Gypsophila  was  found  by  Rochleder  to  contain  52*65  carbon  and  7*34 
hydrogen. 
Pure  saponin  is  a  very  white  amorphous  inodorous  powder,  which 
excites  sneezing  when  inhaled  by  the  nostrils  ;  it  has  a  pungent  disa- 
greeable taste,  and  is  poisonous ;  dissolves  very  freely  in  water,  but  is 
insoluble  in  ether,  benzene,  and  chloroform,  and  only  slightly  soluble 
in  alcohol.  Heated  on  platinum  foil,  it  decomposes,  emitting  an  odor 
of  burnt  sugar,  and  leaving  a  porous  residue  difficult  to  burn.  Saponin 
is  lsevogyrate,  like  most  glucosides;  specific  rotatory  power  [a]D  =  — 
7*30 :  it  is  the  least  optically  active  of  all  known  glucosides. 
Saponin,  as  already  observed,  is  remarkable  for  the  power  of  its 
aqueous  solution  to  dissolve  salts  which  are  insoluble  in  water.  When 
its  aqueous  solution,  mixed  with  lead  acetate,  is  precipitated  by  hydrogen 
sulphide  and  filtered  the  liquid  which  passes  through  is  black  from 
dissolved  lead  sulphide,  which  may  be  precipitated  from  it  by  adding 
