Anoio°beriPS5rm-}       Assay  of  Wild  Cherry  Bark.  535 
ground  into  fine  powder  and  each  sample  placed  in  a  glass-stoppered 
bottle. 
The  method  of  estimation  was  based  upon  the  conversion  of  the 
glucoside  into  hydrocyanic  acid  and  a  volatile  oil;  second,  upon  the 
distillation  of  the  hydrocyanic  acid  to  separate  it  from  the  bark;  and 
third,  upon  the  estimation  of  the  hydrocyanic  acid.  Two  methods 
were  used.    The  details  of  the  operations  are  as  follows : 
First  method. — Ten  grammes  of  the  drug  were  placed  in  a  small 
flask,  about  100  c.c.  of  water  were  added,  corked  tightly,  macerated 
for  twelve  hours,  and  connected  with  a  large  condenser.  A  moder- 
ate heat  was  then  applied  and  the  distillate  conducted  into  a  solution 
of  potassium  hydroxide,  the  distillation  being  continued  almost  to 
dryness.  About  150  c.c.  more  of  distilled  water  were  added  through 
a  glass-stoppered  thistle  tube,  and  distillation  continued  as  before. 
This  operation  was  repeated  not  less  than  four  times  to  secure  the 
absolute  removal  of  all  the  hydrocyanic  acid  from  the  drug,  after 
which  the  condenser  was  thoroughly  rinsed  to  remove  any  adhering 
hydrocyanic  acid.  The  amount  of  acid  was  then  estimated  volu- 
metrically,  by  titrating  the  slightly  alkaline  solution  of  potassium 
cyanide  with  decinormal  silver  nitrate  solution. 
The  second  method  of  estimation  was  as  follows :  The  drug  was 
macerated  and  distillation  continued  as  in  the  first  method,  but  this 
time  the  distillate  was  conducted  into  a  solution  of  silver  nitrate. 
An  insoluble  silver  cyanide  was  formed.  The  precipitate  was 
allowed  to  settle,  the  supernatant  liquid  decanted  through  small 
counterpoised  filters,  the  precipitate  transferred  to  the  filter,  washed, 
dried  and  weighed. 
The  glucoside  was  estimated  without  decomposition,  as  follows  : 
Five  grammes  of  the  drug  were  placed  in  a  Soxhlet's  apparatus, 
extracted  with  absolute  alcohol  for  six  hours,  and  the  alcoholic  ex- 
tract evaporated  to  a  syrupy  consistence.  An  excess  of  ether  was 
added,  precipitating  all  the  glucoside,  together  with  some  coloring 
matter  and  resin.  The  precipitate  was  washed  with  ether,  on  the 
filter,  and  treated  for  a  short  time  with  100  c.c.  of  boiling  distilled 
water.  The  solution  was  allowed  to  cool.  The  glucoside  in  solution 
was  filtered,  the  filter  washed  with  a  little  hot  water,  and  the  wash- 
ings and  filtrate  mixed.  The  solution  was  evaporated  to  dryness  in 
a  weighed  porcelain  dish,  and  again  weighed ;  the  increase  in  weight 
represented  the  glucoside. 
