58 
ON  THE  RANCIDITY  OF  FATS. 
prescribed  proportions,  and  a  smaller  quantity  using  benzoin- 
ated  lard.  To  small  portions  of  the  former  I  added  essential 
oils,  in  the  proportion  of  four  drops  to  the  ounce.  The  oils  I 
used  were  fennel,  almond,  bergamotte,  cassia,  turpentine,  laven- 
der, neroli,  lemon,  rose,  rosemary,  caraway,  nutmeg,  savine, 
pimento^  cumin,  clove  and  sassafras.  I  also  tried  creasote, 
balsam  of  Peru,  Venice  turpentine,  and  powdered  guaiacum. 
These  were  all  put  into  willow  boxes,  and,  in  order  to  hasten 
the  reaction,  placed  in  a  warm  situation,  whose  temperature 
ranged  between  70°  and  80°. 
On  the  28th  of  the  following  February  (85  days),  I  observed 
the  ointment  made  with  plain  lard  to  be  slightly  discolored. 
By  the  11th  of  March  (96  days),  the  change  had  developed  it- 
self in  the  lavender,  neroli,  lemon,  rosemary  and  caraway, 
which,  with  the  plain,  were  most  discolored.  Next  came  cassia, 
Venice  turpentine,  less  discolored,  and  then  fennel,  almond,  and 
bergamotte,  least  discolored.  In  some  cases  the  interior  was 
more  discolored  than  the  exterior.  April  19th,  1862,  (135 
days),  the  most  changed  were  the  plain  and  bergamotte ;  the 
next  best,  cassia,  lemon,  rosemary,  lavender,  almond,  and  tur- 
pentine ;  the  least  changed,  neroli,  Venice  turpentine,  fennel, 
and  caraway.  The  rest  continued  good.  On  the  2d  of  June 
(179  days),  the  only  kinds  remaining  undiscolored  were  rose, 
pimento,  clove,  creasote,  cumin,  sassafras,  guaiacum,  and  bal- 
sam of  Peru,  the  least  affected  of  the  remainder  being  benzoin, 
which  now  had  given  way. 
By  the  10th  of  September,  (279  days),  rose  and  cumin  had 
become  discolored,  leaving  good  only  clove,  pimento,  Peruvian 
balsam,  sassafras,  guaiacum,  and  creasote,  all  of  which  at  the 
present  date  are  apparently  as  good  as  ever. 
December  5th'  of  the  following  year  (1862),  I  put  by,  under 
the  same  circumstances,  another  series  of  ointments  containing 
four  drops  to  the  ounce,  and  a  second  series  containing  only 
two  drops  to  the  ounce  of  the  following  oils,  etc. : — Clove,  sas- 
safras, pimento,  balsam  of  Peru,  and  creasote, — those,  in  fact, 
that  had  comported  themselves  best  on  the  prior  occasion. 
By  May  5th,  1862  (151  days),  the  plain  ointment  was  spoiled. 
By  August  11th,  1862  (249  days),  the  benzoinated  and  No.  2, 
sassafras.    At  the  present  date  (August  29th,  1864),  balsam  of 
