260  Pharmacy  of  Liquid  Petrolatum.  {AmjJu°nUe!'i?oh3arm" 
weigh.  Connect  and  repeat  the  latter  operations  until  constant 
weight  is  obtained ;  the  difference  between  the  original  weight  ot 
the  apparatus  and  that  after  reaction  with  the  acid  and  displace- 
ment of  the  carbon  dioxide  is  the  weight  of  the  liberated  carbon 
dioxide. 
The  two  drying  flasks  are  necessary  to  protect  the  apparatus  from 
increase  in  weight  due  to  absorption  of  extraneous  moisture. 
THE  PHARMACY  OF  LIQUID  PETROLATUM. 
By  B.  Fui^erton  Cook,  P.D. 
Liquid  petrolatum,  described  in  the  United  States  Pharmacopoeia 
as  "a  mixture  of  hydrocarbons,  chiefly  of  the  marsh-gas  series, 
obtained  by  distilling  off  the  lighter  and  more  volatile  portions  from 
petroleum  and  purifying  the  residue  when  it  has  the  desired  consist- 
ence," was  first  officially  recognized  in  1890. 
Although  this  substance  is  not  identical  with  the  more  or  less 
crude  petroleum  oils  that  have  been  known  and  used  since  the 
earliest  historical  periods,  having  been  mentioned  by  Herodotus, 
and  probably  played  some  part  in  the  rites  of  the  fire-worshipers  in 
Persia,  nevertheless,  this  purer  product  has,  to-day,  largely  replaced 
those  cruder  oils  in  both  medicine  and  pharmacy. 
While  there  is  a  broad  field  of  interest  for  an  historical  study  of 
the  medicinal  uses  to  which  they  were  applied  under  the  various 
names  of  Oil  of  Baku,  Mecca  Oil,  St.  Quirinu's  Oil,  Oil  of  Modena 
or  Seneca  Oil  (see  Pharmaceutical  Journal,  1897),  yet  this  paper  has 
been  limited  to  the  practical  part  it  takes  in  present-day  pharmacy. 
There  are  at  least  four  distinct  fields  into  which  it  has  entered  that 
will  be  spoken  of  in  turn :  they  are,  first,  the  administration  of  the 
oil  internally  as  a  nutrient  in  wasting  diseases;  secondly,  as  a  sooth- 
ing application  to  inflamed  mucous  membrane ;  thirdly,  as  a  part 
base  for  ointments,  and  lastly,  as  the  carrier,  when  dissolved  in 
ammonium  oleate,  of  various  active  medicaments  which  are  to  be 
applied  externally.  This  form  of  liquid  petrolatum  has  been  known 
under  the  trade  names  of  Vasogen  and  Valsol,  and  also  as  oxygen- 
ated petrolatum  and  petrox.  Mr.  M.  I.  Wilbert,  in  a  paper  which 
appeared  in  the  American  Journal  of  Pharmacy  (1901,  p.  220), 
has  thoroughly  canvassed  the  pharmacy  of  this  preparation, 
and  also  its  medical  uses,  and  you  will  be  referred  to  that  article 
for  any  further  details. 
