}  The  Adminiftration  of  Phosphorus,  -  415 
it  is  not  entirely  persistent  after  cooling.  The  decoloration  is  a  sign  of 
the  good  quality  of  the  oil ;  for  the  red-tinted  oils,  extracted  from  the 
seeds  of  various  species  of  Rosace^e^  are  very  slightly  decolorized. 
The  color  is  injurious  to  the  appearance  of  the  product,  although  not 
to  the  solvent  or  keeping  properties  of  the  oil.  The  oil  after  being  raised 
to  a  temperature  of  from  200°  to  250°  C,  is  left  to  cool  partially,  and 
then  filtered,  still  hot,  through  paper.  The  vessel  into  which  it  is 
received  should  be  scrupulously  dry  and  clean.  This  oil  will  dissolve 
about  one-eightieth  of  its  weight  of  phosphorus,  but  it  is  recommended 
not  to  dissolve  more  than  i  per  cent.,  so  as  to  avoid  all  danger  of  super- 
saturation.  A  ground-stoppered  flask  is  then  filled  to  nine-tenths  of  its 
capacity  with  the  oil,  and  i  per  cent,  of  its  weight  of  phosphorus  added. 
The  phosphorus,  cut  under  water  and  weighed  after  drying  with  a 
fine  linen  cloth,  should  be  perfectly  transparent  and  free  from  either 
red  or  white  phosphorus.  The  flask  is  placed  up  to  the  neck  in  a  boiling- 
water  bath  ;  and  when  sufliciently  heated  it  is  closed,  and  after  the  tem- 
perature has  risen  to  about  70°  or  80°  C.  the  bottle  is  well  agitated 
until  the  solution  of  the  phosphorus  is  complete.  Dr.  Mehu  does  not 
operate  upon  more  than  a  kilogram  of  oil  at  a  time,  so  that  the  agita- 
tion may  not  be  too  diflicult.  When  the  flask  has  cooled,  if  it  be 
opened  in  the  dark,  the  oil  presents  a  beautiful  phosphorescence  and 
emits  luminous  vapors.  A  few  drops  of  ether  poured  upon  the  stopper 
at  the  moment  of  opening  the  bottle  suflices  to  prevent  this  oxidation 
and  the  phosphorescence. 
Most  fixed  oils  dissolve  nearly  one-eightieth  of  their  weight  of  phos- 
phorus ;  castor  oil,  however,  dissolves  only  one  part  in  one  hundred 
and  twenty  at  ordinary  temperature.  Experiment  has  shown  that  with 
arsenious  acid  the  results  are  different,  castor  oil  dissolving  three  parts 
in  a  thousand,  whilst  oil  of  almonds  dissolves  scarcely  one  part.  Dr. 
M^hu's  experiments  have  shown  also  that  the  essential  oils  which  con- 
tain no  oxygen,  alone  prevent  the  phosphorescence  of  phosphorated  oil  \ 
oxygenated  essential  oils  do  not  possess  that  power. 
The  pharmaceutical  form  which,  in  Dr.  M^hu's  opinion,  lends  itself 
best  to  the  continued  administration  of  phosphorated  oil  is  that  of  cap- 
sules containing  one  milligram.  He  also  gives  the  following  formula  for 
an  emulsion  : 
Phosphorated  Oil  (i  per  cent.),  ....      o'lo  gram. 
Syrup  of  Gum,      .  .  ,  .  .  ,  30'oo  *' 
Distilled  Peppermint  Water,  ,  .  .  .  -  3o-od 
