3H 
The  Influence  of  Oxygen  on  Olive  Oil.  { 
A.m.  Jour.  Pharm. 
July,  1907. 
1.  In  diffused  sunlight 
2.  Same  specimen  .  . 
77*65 
77-21 
275-25 
275-25 
Mean 
77'43 
Mean  275*25 
1.  In  darkness  .  . 
2.  Same  specimen 
70-30 
70-07 
202-34 
201*52 
Mean 
70-18 
201-93 
The  results  of  the  experimentation  here  detailed  demonstrate 
that  the  influence  of  oxygen  on  olive  oil  is  to  decrease  the  iodine 
number  and  at  the  same  time  to  increase  the  saponification  number. 
It  also  acts  decidedly  towards  causing  the  oil  to  become  rancid,  and 
in  addition  it  diminishes  the  intensity  of  color  possessed  originally 
by  the  oil.  The  unsterilized  oil  exposed  to  diffused  sunlight  yielded 
a  slightly  higher  iodine  number  than  the  sterilized  oil  exposed  to 
diffused  sunlight,  but  the  latter  oil  gave  a  slightly  higher  saponifi- 
cation number.  The  sterilized  oil  kept  in  darkness  gave  a  slightly 
higher  iodine  number  than  the  sterilized  oil  exposed  to  diffused 
sunlight,  while  the  latter  gave  a  somewhat  higher  saponification 
number  than  the  sterilized  oil  kept  in  darkness. 
As  to  the  influence  of  nitrogen  on  the  iodine  and  saponification 
numbers  the  experiments  show  that  whether  under  conditions  ot 
sterilization  or  unsterilization  practically  no  change  is  caused  in  the 
iodine  number,  but  in  the  sterilized  oil  in  the  case  of  nitrogen,  as 
well  as  in  the  case  of  oxygen,  there  is  an  increase  in  the  saponifica- 
tion number.  This  is  probably  not  due  to  any  action  of  the  nitrogen 
or  oxygen  upon  the  oil,  but  to  a  cleavage  of  a  portion  of  the  oil 
that  may  occur  at  the  temperature  at  which  sterilization  was  effected. 
In  every  case  with  the  flask  containing  an  atmosphere  consisting 
wholly  of  nitrogen  the  oil  remained  sweet  and  without  the  slightest 
indication  of  its  having  become  rancid. 
Winckel,1  from  experiments  performed  with  oleic  acid,  has  come 
to  the  conclusion  that  fats  do  not  become  rancid  because  of  the 
action  of  enzymes,  but  that  of  first  importance  in  the  production  of 
rancidity  is  the  oxidizing  action  of  oxygen.  The  experiments  de- 
scribed in  this  article  confirm  the  view  of  Winckel.  Our  experiments 
show  that  light  and  moisture  appear  to  have  no  influence  upon  the 
oil  becoming  rancid,  because  the  flasks  containing  the  oil  and 
1  Winckel,  Apoth.  Zeitung,  August,  1905,  p.  690. 
