^ApSim™'}  Oil  of  Bitter  Almonds.  159 
ing  section  of  the  description  of  this  test  in  the  U.S. P.  should  be  so 
modified  in  wording  as  to  obviate  the  fallacy  of  its  present  reading. 
Hydrocyanic  Test,  Qualitative. — This  well-known  test  requires 
no  comment,  and  we  may  pass  it  by,  merely  calling  attention  to  the 
fact  that  six  of  the  samples,  which  were  in  whole  or  part  evidently 
artificial  benzaldehyde,  yet  contained  hydrocyanic  acid,  showing  that 
an  attempt  had  been  made  to  duplicate  more  nearly  the  genuine  oil.. 
Hydrocyanic  Acid  Estimation. — The  determination  of  hydrocyanic 
acid  present  in  oil  of  bitter  almonds  may  be  accomplished  with  a  fair 
degree  of  accuracy  with  the  method  given  in  the  U.S. P.,  and  although 
the  U  S.P.  specifies  that  magnesium  hydroxide  free  from  chlorides 
shall  be  used,  yet  an  hydroxide  containing  chlorides  will  be  equally 
useful  if  a  blank  test  be  run  alongside  of  the  assay.  The  quantities 
found  range  from  0  69  per  cent,  in  number  15  to  the  very  high 
figure  of  6  44  in  number  9,  which  sample  is  also  the  one  having  the 
highest  specific  gravity.  Numbers  13  and  31  are  below  the  U.S.P. 
standard,  while  the  remaining  four  are  within  the  limits  of  2  to  4 
per  cent.  Three  of  these  four,  however,  it  will  be  seen  by  reference 
to  the  chlorinated  compound  test,  were  not  natural  oils. 
Benzaldehyde  Estimation. — Few  practical  problems  in  connection 
with  the  whole  field  of  volatile  oil  analysis  have  recently  attracted 
more  attention  than  the  methods  for  the  estimation  of  aldehydic  or 
ketonic  constituents.  The  method  of  estimating  such  constituents 
by  use  of  acid  or  neutral  sulphite  of  sodium  received  its  early  and 
widest  application  to  the  estimation  of  citral  in  lemon  oil,  but  has 
since  been  extended  to  various  other  oils,  and  among  the  more  recent 
applications  of  the  method  is  that  to  oil  of  bitter  almonds.  In  con- 
nection with  work  upon  a  large  number  of  oils  of  this  character, 
Burgess  {Analyst,  1904,  78)  applied  the  method  to  benzaldehyde 
and  oil  of  bitter  almonds,  and  carried  out  the  estimation  by  meas- 
urement of  the  uncombined  oil.  More  recently,  S.  S.  Sadtler  has 
applied  the  observations  of  Tiemann  [Bcrichte,  31,  3334),  who 
demonstrated  the  liberation  of  alkali  by  the  action  of  sodium  sulphite 
on  an  aldehyde,  to  the  determination  of  various  aldehydes  and  among 
them  benzaldehyde  in  oil  of  bitter  almonds.  In  a  paper  read  before 
the  Chemical  Section  of  the  Franklin  Institute  {Jour.  Franklin  In- 
stitute, December  1903)  he  described  a  method  for  the  quantitative 
estimation  of  aldehydes  and  ketones  based  upon  this  reaction  and 
the  determination  of  the  alkali  formed.    Another  article  of  similar 
