Am.  Jour,.  Pharm. 
Nov.,  1885. 
Cotton  Seed  Oil. 
567 
below  '920  and  never  above  '923.  The  greater  number  of  samples 
average  from  -920  to  -921. 
The  next  point  I  would  notice  is  the  "  congealing  "  point.  This^  of 
course,  is  very  much  a  matter  of  arrangement  on  the  part  of  the 
refiner,  but  I  am  speaking  at  present  of  this  oil  as  it  is  to  be  found 
commercially.  Even  with  the  uniformity  of  specific  gravity  just  men- 
tioned, I  have  found  considerable  variation  in  the  freezing  point,  some 
samples  beginning  to  thicken  at  a  temperature  of  45°F.,  or  even 
above  this,  while  others  did  not  thicken  until  some  degrees  below  32°. 
The  former  samples,  I  may  state,  were  mostly  home  prepared,  the  lat- 
ter, American.  I  merely  mention  this  point  to  show  that  a  consider- 
able variation  may  exist  in  the  physical  properties  of  many  genuine 
oils  at  present  in  circulation. 
Another  point  which  I  endeavored  to  determine  was  the  keeping 
properties  of  this  oil.  I  have  noticed,  elsewhere,  the  case  of  a  sample 
which  I  had  in  my  possession  for  nearly  ten  years,  and  which,  although 
devoid  of  the  nutty  sweetness  of  a  fresh  sam})le,  had  not  developed 
rancidity  or  smell  to  any  extent.  I  have  here  two  samples,  one  of 
American  origin,  and  one  home  prepared,  which  I  have  had  exposed 
to  bright  sunshine  for  nearly  four  months.  The  members  will  be  able 
to  judge  for  themselves  of  their  keeping  properties  under  this  crucial 
test.  They  have  both  bleached  somewhat  lighter  in  color,  but  they 
have  not  developed  any  smell,  while  the  taste  is  still  sweet  and  nutty, 
and  no  test  that  I  have  been  able  to  apply  has  detected  the  least  acid- 
ity. Under  similar  conditions  olive  oil  develops  both  taste  and  smell, 
and  acidity  also  may  readily  be  detected. 
Another  point  which  1  was  anxious  to  determine,  and  which  is 
important  from  a  pharmaceutical  point  of  view,  was  the  place  which 
cotton  seed  oil  held  among  the  fixed  oils  as  regards  drying  properties. 
Opinion  seems  to  be  pretty  much  divided  upon  this  point,  but  my 
experiments  show  that  those  authorities  who  place  this  oil  midway 
between  a  drying  and  a  non-drying  oil  are  about  correct.  Taking  for 
example  five  weighed  quantities  of  cotton  I  saturated  them  with  a 
weighed  quantity  of  home  prepared  cotton  seed  oil,  of  American  oil, 
and  of  olive,  almond  and  linseed  oils,  respectively,  and  placed  them 
on  the  water-bath.  Six  hours'  exposure  to  this  heat  having  made  no 
perceptible  change  on  any  of  the  samples,  with  the  exception  of  the 
linseed,  I  transferred  them  to  the  sand-bath  and  carefully  cooked  them 
over  it  until  the  linseed  sample  was  hard  and  dry.    At  this  stage  the 
