268     CRYSTALLINE  DEPOSIT  FROM  OIL  OF  BITTER  ALMONDS. 
The  crystals  had  a  deep  yellow  color,  and  were  strongly  im- 
pregnated with  oil  of  bitter  almonds.  As  much  of  the  oil  as 
possible  was  removed  by  strongly  compressing  the  crystals  be- 
tween folds  of  blotting-paper.  The  crystals  were  then  digested 
with  boiling  water,  in  which  they  readily  dissolved.  After  re- 
peated solutions  and  crystallizations,  they  presented  the  usual 
characters  of  benzoic  acid.  On  analysis,  0.4215  grm.  substance 
dried  at  212°  F.,  when  burnt  in  a  current  of  oxygen  gas,  gave 
1,069  carbonic  acid  and  0.2005  water  = 
Calculated  numbers.        Found  numbers. 
14  C.       .       .      68.853     .      .  69.16T 
6H.       .       .       4  915     .      .  5.283 
4  0.       .       .      26.232     .      .  25.460 
100.000  100.000 
The  silver  salt  was  prepared  by  neutralizing  the  acid  with  am- 
monia, and  then  adding  a  solution  of  nitrate  of  silver.  When 
subjected  to  analysis,  0.3883  grm.  salt  gave  0.525  carbonic  acid 
and  0.317  water. 
L1711  grm.  salt  gave  0.5516  silver. 
Calculated  numbers.        Found  numbers. 
AgO.       .       .        50.654      .      .    50.533  . 
14  C.       .       .        36.684      .      .  36.909 
5H.      .      .         2.183      .      .  2.317 
3  0.      .      .       10.479      .      .  10.241 
100.000  100.000 
From  these  results  it  is  clear  that  the  crystalline  deposits  from 
oil  of  bitter  almonds  examined  by  me  were  simply  benzoic  acid, 
and  this  I  have  reason  to  believe  was  also  the  case  with  two  out 
of  three  samples  described  by  Dr.  Pereira ;  for  through  the  kind- 
ness of  Professor  Redwood,  I  obtained  three  small  specimens  of 
these  deposits  from  Dr.  Pereira's  collection,  now  in  the  posses- 
sion of  the  Pharmaceutical  Society.  That  marked  No.  1,  I  found 
to  be  simply  benzoic  acid.  I  received  also  a  specimen  given  to 
the  Pharmaceutical  Society  by  Mr.  Whipple  ;  it  was  also  benzoic 
acid.  The  specimen  marked  No,  3,  and  which  amounted  only  to 
a  few  grains  in  weight,  was  that  examined  by  Drs.  Pereira  and 
Letheby.    It  consisted  of  small,  acicular,  lemon-yellow  crystals, 
