532   PAPERS  BEAD  AT  THE  BRITISH  PHARM.  CONFERENCE. 
and  apply  the  test  to  the  distillate.  The  author  added  that, 
since  completing  the  paper,  he  had  found  that  acetone  was  the 
principle  which  prevented  the  formation  of  a  precipitate  by 
methylated  spirit. 
ON  THE  PUEITY  OF  SULPHATE  OF  QUININE  OF  COMMERCE. 
BY  MR.  W.  WALTER  STODDART. 
"  The  author's  experiments  showed  that  quinine,  and  not  cin- 
chonine,  must  be  generally  sought  for  as  the  chief  impurity  in 
commercial  sulphate  of  quinine.  After  pointing  out  the  objec- 
tions to  the  tests  of  Bouchardat  and  Pasteur,  Stokes,  Herapath, 
Brande  and  Pelletier,  Mr.  Stoddart  proposed  a  modification  of 
Liebig's,  and  gave  the  details  of  its  application.  A  second 
trustworthy  and  ready  test,  for  all  possessing  microscopes,  was 
sulphocyanide  of  potassium.  If  a  drop  of  a  solution  of  the  lat- 
ter salt  were  added  to  a  drop  of  saturated  and  neutral  solution 
of  the  suspected  quinine,  and  the  mixture  observed  by  the  micro- 
scope crystals  of  sulphocyanide  of  quinidine  and  sulphocyanide 
of  cinchonine,  both  of  highly  characteristic  form  and  wholly  dis- 
tinct from  the  sulphocyanide  of  quinidine  formed  at  the  same  time, 
would  be  observed  if  either  quinidine  or  cinchonine  were  present. 
For  quantitative  determination,  the  Reporter  employed  De  Vry's 
iodide  of  potassium  reaction,  and  detailed  the  results  of  his  ana- 
lyses of  samples  of  sulphate  of  quinine  from  Messrs.  Howards  & 
Sons,  De  Lisle  &  Co.  (Pelletiers),  Mr.  J.  Hulle,  Messrs.  Herring 
&  Co.,  and  a  German  specimen.  It  was,  he  said,  gratifying  to 
be  able  to  affirm  that  sulphate  of  quinine,  if  purchased  in  bottles 
or  sealed  packets,  as  sent  out  by  the  makers  or  obtained  through 
well  known  wholesale  houses,  is  commercially  pure  and  quite  fit 
for  medicinal  use.  It  was  the  chemist's  own  fault  if  he  were  not 
supplied  with  an  article  of  sufficient  purity." — Proo.  Brit. 
Pharm,  Oonf.  1864. 
ON  THE  RANCIDITY  OF  FATS.     BY  T.  B.  GROVES,  F.R.C.S. 
The  author  states  the  occasion  of  his  paper  to  have  been  the 
observation  of  the  preservative  effect  of  aromatic  oils  on  oxide 
of  mercury  ointment,  which  induced  him  to  compare  the  rela- 
tive efficacy  of  the  various  essential  oils  of  commerce,  both  as 
regards  mixed  ointments  and  the  pure  fats. 
