"^°''Dec\Sr'°'''}        Solubility  of  Mercuric  Iodide  in  Fats.  611 
without  any  sensible  deposit  taking  place  during  cooling,  or  even  after 
eight  days. 
Olive  Oil. — At  100°C.  olive  oil  l:)ehaves  nearly  like  almond  oil 
towards  biniodide  of  mercury.  It  deposits  slowly  the  excess  of  bin- 
iodide,  and  does  not  appear  to  retain  more  of  it  when  cold. 
Poppy  Seed  Oil. — At  about  100°C.  poppy  seed  oil  dissolves  notably 
more  biniodide  of  mercury  than  almond  oil.  At  that  temperature  I 
have  dissolved  15'35  grams  of  biniodide  of  mercury  in  1,000  grams 
of  the  oil.  When  cold,  poppy  seed  oil  retains  in  solution  three  times 
as  much  of  the  biniodide  as  almond  oil.  A  solution  of  10  grams  of 
biniodide  of  mercury  in  1,000  grams  of  poppy  seed  oil  did  not  become 
turbid  even  after  remaining  ten  days  in  the  cellar.  This  experiment 
was  made  twice. 
Nut  Oil. — At  about  100°C.  nut  oil  dissolves  15  grams  of  biniodide 
of  mercury  in  1,000  grams.  In  the  cold,  nut  oil  retains  in  solution 
about  13  grams  of  the  biniodide  per  kilogram. 
Poppy  seed  oil  and  nut  oil  are  both  drying  oils ;  they  are  distin- 
giiished  from  almond  oil  and  olive  oil  by  possessing  a  solvent  power  a 
little  greater  when  hot,  and  nearly  three  times  as  great  when  cold. 
Castor  Oil. — Castor  oil  is  one  of  the  most  powerful  solvents  of  bin- 
iodide of  mercury.  By  heating  in  a  porcelain  capsule,  in  a  steam- 
bath,  to  about  100°C.,  and  using  a  small  glass  pestle  as  a  stirrer,  it  is 
possible  to  dissolve  1  gram  of  biniodide  of  mercury  in  25  grams  of 
eastor  oil,  or  40  grams  in  1,000  grams  of  oil.  Upon  being  left  to 
cool,  the  oil  deposits  only  half  the  dissolved  biniodide. 
A  solution  of  1  gram  of  biniodide  of  mercury  in  40  grams  of  cas- 
tor oil  still  deposits  slowly  red  crystals  of  the  biniodide. 
A  solution  of  1  gram  of  biniodide  of  mercury  in  50  grams  of  castor 
oil  does  not  become  turbid  in  cooling,  and  even  after  standing  a  month 
at  the  ordinary  temperature  it  remains  absolutely  clear.  This  solution 
contains,  therefore,  one-fiftieth  of  its  weight  of  biniodide  of  mercury. 
It  appears  to  me  capable  of  satisfying  all  therapeutic  requirements, 
The  combination  of  the  biniodide  with  the  bichloride  of  mercury 
dissolves  readily  in  the  oil.  At  the  temperature  of  the  vapor-bath  it 
is  easy  to  dissolve  80  grams  of  biniodide  of  mercury  and  48  grams  of 
bichloride  of  mercury  in  1,000  grams  of  castor  oil.  Only  a  small 
proportion  of  the  mixture  separates  during  the  cooling;  the  deposit 
contains  a  whitish  crystalline  combination  of  the  two  constituents. 
The  castor  oil  retains,  when  cold,  nearly  10  per  cent,  of  a  mixture  of 
