536  Assay  of  Wild  Cherry  Bark.         {A m0£p£m' 
In  order  to  test  the  accuracy  of  the  above  method,  and  to  ascer- 
tain the  number  of  distillations  necessary  to  obtain  all  of  the  acid, 
the  distillates  were  collected  separately,  and  the  acid  in  each  esti- 
mated with  the  following  results : 
First  distillate  .  .  .  .   17 T5  per  cent,  hydrocyanic  acid. 
Second    "    11*2       "  "  " 
Third  !.  .  .  .  .  .  .  .  ...    5*25  -  ^ 
Fourth    "       ...........     105      "  'f 
Fifth       ' ■••       .  .  .  ...  .  .  ,  ,  .  .     o-oo      "  " 
To  verify  the  above,  a  number  of  experiments  were  made  by  add- 
ing a  known  quantity  of  hydrocyanic  acid  to  previously  exhausted 
bark  and  to  other  drugs  like  cinnamon.  These  were  subjected  to 
distillation  under  exactly  the  same  conditions  as  in  the  preceding 
case,  with  the  following  results  : 
First  distillate   56*0  per  cent,  of  total  acid  added. 
Second    "   32*0      "  " 
Third      "    8"o 
Fourth    "   28  " 
Fifth       "   .  .  .    o-o      "  " 
In  no  case  could  all  of  the  hydrocyanic  acid  which  was  mixed  with 
the  powder  be  recovered.    The  loss  was  about  1  per  cent. 
ASSAY  OF  BARK. 
Average  results  of  several  estimations  upon  each  sample  of  the 
bark  : 
Thick  Bark. 
First  method,  No.  1,    -035  per  cent,  of  hydrocyanic  acid. 
2,  0-35 
3,0-34 
4,0-323 
5,0-348       "  " 
vSecond  method,  "    1,  C319       "  "         "  " 
2,  0-323 
Thin  Bark. 
First  method,  No.  1,  0-24  per  cent,  of  hydrocyanic  acid. 
"  "    2,  0-264 
"    3>  0-27 
"  "    4,  0*268 
Second  method,  "    r,  0*229 
"  2,0-238 
Yield  of  amygdalin  (or  allied  substance) 
Thick  bark,  average  4-12  per  cent. 
Thin  bark,  average  3*16  per  cent. 
