144       Recent  Literature  Relating  to  Pharmacy.    {ArMSch, 5o!.rm' 
accuracy,  and  some  are  very  much  lower  than  they  should  be. 
Whilst  correct  results  may  follow  in  some  cases,  careful  investigation 
is  needed  betore  the  process  can  be  said  to  be  as  accurate  as  the 
well-known  acetylation  method.  This  is  well  emphasized  in  the  case 
of  sandal  oil  and  santalol.  It  is  established  that  no  pure  sandal  oil 
yields  less  than  about  90  per  cent,  of  santalol,  and  that  pure  santalol 
yields  results  agreeing  with  over  100  per  cent.,  rather  than  under; 
but  the  new  process  gives  only  81  per  cent,  for  the  oil,  and  95  per 
cent,  for  the  pure  alcohol. 
The  second  of  the  papers  deals  with  Umney's  and  Thoms's  pro- 
cesses for  the  determination  of  eugenol  in  oil  of  cloves.  It  is  pointed 
out  (as  is  well  known)  that  the  use  of  10-per-cent.  alkali  causes  some 
of  the  non-phenolic  constituents  of  the  oil  to  be  absorbed,  but  that 
better  results  are  obtained  by  the  use  of  3  to  4  per  cent,  alkali. 
Indeed,  oils  prepared  by  mixing  known  quantities  of  eugenol  and 
terpenes  gave  results  within  i  to  2  per  cent.,  and  very  reliable  results 
may  usually  be  obtained  by  the  absorption-process  with  dilute  alkali. 
Three  samples  were  prepared  from  pure  eugenol  and  pure  sesqui- 
terpenes of  85  per  cent.,  90  per  cent.,  and  95  per  cent,  strength. 
The  three  results  in  each  case  are  as  follows  : 
Per  cent.  Per  cent.  Per  cent. 
Actual  eugenol  value  85*0            90*0  95*0 
Acetic  pyridine  method  .........  84*4            89^5  95*9 
Absorption  process  (dilute)  85*3             90*0  95*0 
Thoms's  process                                  .  81-5            87*2  91*4 
Two  samples  of  normal  clove  oil  also  gave  results  in  which  the 
absorption  and  the  esterification  processes  were  in  accord.  Two 
other  samples  which  were  examined  showed  results  in  which 
Thoms's  process  was  in  very  good  agreement  with  the  acetic-pyri- 
dine  method  ;  whilst  Umney's  process  gave  far  too  high  figures — as 
much  as  95  per  cent.,  against  80  per  cent,  by  the  other  two  processes. 
The  figures  appear  to  us  most  unsatisfactory  and  unconvincing ;  but 
the  authors  sum  up  their  conclusions  as  follows  : — (1)  The  esterifica- 
tion-process  with  acetic  anhydride  and  pyridine  serves  to  determine 
the  eugenol  in  oil  of  cloves  so  long  as  no  other  phenol  or  alcohol  is 
assumed  to  be  present.  (2)  Umney's  method  can  lead  to  most 
erratic  conclusions,  except  when  the  clove  oil  is  one  whose  physical 
characters  are  quite  normal  throughout.  (3)  Thoms's  process  gives 
too  low  results  when  the  oil  contains  a  high  amount  of  nonphenolic 
constituents. — Chemist  and  Druggist,  Dec,  1901,  p.  1053. 
