ADecimbe^9OT?'}      Some  Official  Standards  and  Tests.  555 
Oil  of  Sandalwood  we  found  U.S. P.  with  a  high  percentage  of 
santalol  and  in  all  (15)  except  two  samples,  the  optical  rotation  was 
between  —  1 6°  to  —  200,  according  to  U.S.P.  The  two  other 
samples  read  —  10.50  and  —  11 -2°,  respectively.  Both  assayed 
about  91  per  cent,  santalol. 
We  are  making  at  present  tests  of  this  important  drug  by  frac- 
tional distillation  and  shall  be  glad  to  make  our  results  public  later. 
Under  Oil  of  Anise  the  U.S.P.  says:  u  The  oil  should  be  laevo- 
gyrate,  the  angle  of  rotation  being  —  2°  in  a  lOO-mm.  tube  at 
25 0  C.  (absence  of  oil  of  fennel)."  Looking  up  oil  of  fennel  in  the 
U.S.P.  you  will  find  not  a  word  on  the  optical  rotation  of  the  oil — 
not  even  mentioned  whether  it  should  be  dextro-  or  laevogyrate. 
The  question  is,  "  Would  the  angle  of  rotation  be  increased  or 
decreased  by  the  presence  of  oil  of  fennel  "  ?  What  is  the  reason 
for  omitting  the  angle  of  rotation  in  one  case  and  giving  it  in 
another  ? 
Nitroglycerin. — In  assaying  nitroglycerin  in  solutions  as  well  as  in 
tablets  we  use  Lunge's  Nitrometer  with  the  best  results  in  deter- 
mining the  exact  amount  of  absolute  glyceryl  trinitrate.  It  takes  a 
little  experience  to  work  the  nitrometer  quickly,  but  once  acquainted 
with  it,  it  is  easy  to  make  five  or  more  different  determinations  in 
one  hour.  We  assayed  recently  quite  a  number  of  samples  of  spirits 
of  glonoin,  sold  to  contain  10  per  cent.,  and  found  on  the  average 
only  8-5  per  cent,  absolute  nitroglycerin  by  weight.  As  these  spirits 
enter  all  preparations  containing  nitroglycerin,  it  is  necessary  to 
determine  their  absolute  strength  before  using  them.  Tablets  made 
with  glonoin  lose  30  to  40  per  cent,  in  strength  during  manufac- 
turing, and  it  is  necessary  to  allow  a  large  excess  to  bring  the 
finished  tablets  to  a  required  strength.  The  tablets  seem  to  lose 
during  the  granulation  process,  probably  by  evaporation,  as  granu- 
lations ready  for  the  tablet  machines,  and  the  finished  tablets  them- 
selves, were  found  to  contain  the  same  amount  of  nitroglycerin. 
The  age  does  not  seem  to  have  much  effect  on  the  tablets  because  a 
number  of  lots  assayed  nine  months  ago  show  the  same  respective 
amounts  of  nitroglycerin  now. 
Potassium  Arsenite. — In  assaying  potassium  arsenite  powder  for 
arsenous  acid  care  should  be  taken  to  use  the  right  formula.  The 
appendix  of  the  U.S.P.,  under  "  List  of  the  elements  and  principal 
pharmacopoeial  chemicals,"  gives  the  formula  for  potassium  arsenite 
