326 
Assay  of  Volatile  Oils. 
(Am.  Jour.  Pharm. 
I       July,  1909. 
filter,  and  evaporate  to  600  c.c. ;  in  this  dissolve  the  sugar  by  heat 
and  when  cold  strain,  add  the  oils,  and  make  up  to  1000  c.c.  with 
water. 
As  an  alternative  formula: 
Fluidextract  buckthorn  berries   200  c.c. 
Oil  of  fennel  2  c.c. 
Oil  of  cassia  2  c.c. 
Syrup,  sufficient  quantity  to  make  1000  c.c. 
Mix. 
THE  USE  OF  THE  CENTRIFUGE  IN  THE  ASSAY  OF 
VOLATILE  OILS. 
By  Frank  X.  Moerk. 
In  a  paper  presented  to  the  American  Pharmaceutical  Associa- 
tion at  the  1908  meeting,  the  suggestion  was  made  that  the  assays 
of  some  of  the  volatile  oils  could  be  more  conveniently  and  accurately 
made  by  the  use  of  the  centrifuge  than  by  the  official  method  of 
shaking  the  oils  with  reagents  in  a  flask  or  burette,  for  the  reason 
that  in  the  latter  method  it  is  almost  impossible  to  prevent  adhesion 
of  the  oil  to  the  container. 
The  centrifuge  has  been  in  use  as  a  laboratory  apparatus  since 
about  1889,  when  it  was  first  applied  in  rapidly  determining  the  fat 
content  of  milk  and  cream. 
A.  S.  Mitchell  in  the  Journal  of  the  Am.  Chem.  Society,  1889, 
page  1 132,  proposed  a  centrifugal  method  for  determining  lemon  oil 
in  lemon  extracts ;  and  C.  D.  Howard  in  the  same  journal,  1908, 
page  608,  recommended  the  addition  of  a  small  quantity  of  chloro- 
form to  assist  in  the  centrifugal  separation  of  oils  from  flavoring 
extracts.  J.  Hortvet  and  R.  M.  West  in  the  Journ.  Industr.  and 
Engineer.  Chemistry,  1909,  page  84,  published  a  very  valuable  paper 
upon  the  analysis  of  flavoring  extracts  in  which,  after  a  critical 
study  of  the  subject,  the  centrifuge  is  recommended  for  certain 
extracts.  The  above  suggestion,  therefore,  appears  to  be  original 
for  the  examination  of  volatile  oils  for  their  characteristic  con- 
stituents. 
From  the  U.S.P.  assays  the  method  using  the  centrifuge  appeared 
to  be  most  applicable  in  the  assay  of  the  oils  of  cloves,  pimenta, 
