84  Arrow-Poison  of  the  Somalis.  {Am'Sebr;^aTm' 
ARROW-POISON  OF  THE  SOMALIS.1 
By  Arnaud. 
The  Somalis  on  the  east  coast  of  Africa  prepare  an  arrow-poison 
from  the  aqueous  extract  of  the  wood,  and  especially  of  the  root  of 
Ouabaio,  a  tree  which  is  closely  related  to  although  not  identical  with 
Carissa  Schimperi,  a  native  of  Abyssinia. 
A  concentrated  extract  of  the  wood  in  warm  water  was  prepared 
and  precipitated  with  lead  acetate,  the  filtrate  treated  with  hydrogen 
sulphide,  and  the  second  filtrate  boiled  and  afterwards  concentrated  in 
a  vacuum.  The  concentrated  solution  was  mixed  with  six  times  its 
volume  of  alcohol  of  85°,  boiled,  allowed  to  cool  in  shallow  vessels, 
and  the  crystals  thus  obtained  purified  by  recrystallization  first  from 
alcohol  of  85°  and  afterwards  from  water. 
The  ouabain  thus  obtained  contains  no  nitrogen  and  has  the  com- 
position C30H46O12.  It  forms  thin,  white,  nacreous  lamellae  with  no 
taste,  no  smell,  and  a  neutral  reaction.  It  is  almost  insoluble  in  cold 
water,  but  is  readily  soluble  in  boiling  water,  with  a  great  tendency 
to  form  supersaturated  solutions,  and  also  dissolves  readily  in  moder- 
ately concentrated  alcohol,  but  is  almost  insoluble  in  absolute  alcohol 
and  insoluble  in  ether  or  chloroform.  At  180°,  it  becomes  pasty  with 
slight  decomposition,  and  at  200°  it  is  completely  melted.  A  warm 
aqueous  solution  has  a  rotatory  power  [a]  D  =  —  34°.  A  concen- 
trated aqueous  solution  gives  a  precipitate  with  tannin.  When 
boiled  with  dilute  acids,  it  yields  a  reducing  sugar,  and  hence  it  would 
seem  that  ouabain  is  a  glucoside. 
When  ouabain  crystallizes  from  an  aqueous  solution,  it  contains 
7  mols.  H20  which  is  not  completely  expelled  below  130°. 
When  boiled  with  barium  hydroxide,  ouabain  yields  a  barium-deri- 
vative which  when  dried  at  100°  has  the  composition  Ba(C30H47O13)2. 
Ouabain  has  no  toxic  effect  when  introduced  into  the  stomach,  but 
when  introduced  by  subcutaneous  or  intravenous  injection,  it  acts  on 
the  heart  and  produces  death.  2  milligrams  will  kill  a  dog  of  12  kilos, 
in  a  few  minutes. 
Magnesium  silicate  is  recommended  by  Dr.  Debove  in  chronic 
diarrhoea.  Dose  1'5  to  4*0  gm.  To  phthisical  patients*  it  is  given  with  milk 
for  a  prolonged  period. — D.  Med.  Woch. 
1  Compt.  rend.,  cvi.,  1011-1014,  reprinted  from  Jour.  Chem.  Soc,  1888,  p.  848. 
