ON  THE  LEAVES  OF  WILD  CHERRY. 
423 
THE  LEAVES  OF  WILD  CHERRY.    (Cerasus  serotina.) 
Br  William  Procter,  jr. 
The  poisonous  nature  of  the  leaves  of  the  wild  cherry  tree  has 
long  been  known.  Dr.  Coxe,  in  his  Dispensatory,  (edition  1806,) 
says,  "  The  distilled  water  of  the  leaves  is  a  powerful  poison  to 
different  animals,  which  seems  dependent  on  the  presence  of  the 
same  principles  which  exist  in  peach  kernels,  &c,  lately  shown 
to  be  prussic  acid."    It  is  usual  to  import  the  "  Aqua  Lauro- 
cerasi"  of  the  foreign  Pharmacopoeias  to  meet  the  demand  of 
physicians  for  this  form  of  hydrocyanic  acid.     It  is  believed 
that  the  distilled  water  of  the  leaves  of  wild  cherry  may  be  sub- 
stituted for  it  with  perfect  reliability  and  equal  uniformity.  The 
question  has  been  asked,  whence  comes  the  volatile  oil  and  prus- 
sic acid  of  the  cherry  laurel  leaves  ?  Does  amygdalin  exist  in 
them  ?  Liebig  was  not  able  to  detect  amygdalin  in  the  cherry 
laurel  leaf.     He  believes  that  the  oil  is  secreted  in  the  leaf, 
like  other  volatile  oils,  ready  formed,  but  probably  derived  from 
pre-existing  amygdalin  in  the  circulation  of  the  plant.  This 
view  is  rendered  probable  by  experiments  in  the  paper  on  amyg- 
dalin, before  quoted,  in  which  the  presence  of  amygdalin  in 
3mall  quantity  was  detected  in  the  alcoholic  extract  of  dried 
wild  cherry  leaves.    To  ascertain  the  hydrocyanic  acid  value  of 
the  leaves,  1,000  grains,  recently  gathered,  were  cut  and  bruised 
quickly,  put  in  a  bottle,  with  twelve  fluid  ounces  of  water,  ma- 
cerated twenty-four  hours,  and  distilled  till  three  fluid  ounces 
had  passed  over.    The  first  ounce  was  quite  milky,  the  volatile 
oil  in  suspension  soon  separating  from  it,  and  collecting  in  glo- 
bules at  the  bottom  of  the  receiver.    The  greater  part  of  the 
oil  and  the  acid  were  in  this  portion,  because,   when  the  other 
two  ounces  of  water  had  distilled,  they  re- dissolved  the  oil,  and 
retained  it  in  solution.    1,000  grains  of  this  distilled  water, 
when  treated  with  a  weak  solution  of  nitrate  of  silver,  afforded 
3.25  grains  of  cyanide  of  silver,  indicating  0.65  grains  of  anhy- 
drous hydrocyanic   acid  in  that  quantity  of    the  distilled 
water.    It  is  believed,  that  if  the  quantity  of  distilled  water 
was  made  equal  in  weight  to  the  leaves  distilled,  that  the  strength 
of  the  water  would  amount  to  one-tenth  of  one  per  cent,  which 
is  that  of  the  best  cherry  laurel  water. 
