PHARMACEUTICAL  APPLICATIONS  OF  GLYCERINE. 
63 
wards  made  by  Mr.  G.  F.  Wilson,  F.  R.  S.,  of  the  firm  of  Price 
and  Co.,  Vauxhall.  As  a  source  of  glycerine  he  employs  palm- 
oil  bleached  by  exposure  to  the  air  ;  this  is  decomposed  in  suitable 
apparatus  by  steam  at  a  temperature  of  550°  to  600°  F.,  main- 
tained for  several  hours.  The  glycerine  is  then  allowed  to  distil 
over  with  the  fat  acids  and  water,  and  is  concentrated  by  evapo- 
ration. Price's  glycerine  is  well  known  at  home  and  abroad  for 
its  great  superiority  and  almost  absolute  purity,  being  of  neces- 
sity free  from  inorganic  matter.  For,  as  Mr.  Wilson  has  himself 
said,  "  The  only  chemical  agents  used  for  decomposing  the  neu- 
tral fat,  and  separating  its  glycerine,  are  steam  and  heat,  and 
the  only  agents  used  in  purifying  the  glycerine  thus  obtained, 
are  heat  and  steam."  Mr.  Wilson  tells  me  that  they  are  now 
making  one  ton  per  week  of  this  pure  medicinal  glycerine,  and, 
in  order  to  ensure  its  perfect  purity,  it  is  frequently  distilled 
five  or  six  times.  Like  Bennett's  watches,  Price's  glycerine 
leaves  "  nothing  to  be  desired  but  the  money  wherewith  to  buy 
it." 
It  is  in  external  remedies  that  the  greatest  field  appears  to 
be  open  for  the  further  introduction  of  this  substance  in  phar- 
macy, and  I  shall  first  call  attention  to  the  compound  of  starch 
and  glycerine  known  as  "  plasma."  It  had  long  been  thought 
desirable  to  find  a  substitute  for  fatty  matters  in  ointments  not 
liable  to  become  rancid,  and  in  1853  Mr.  Schacht,  of  Clifton,  read 
a  paper  before  the  Pharmaceutical  Society,  in  which  he  proposed 
for  that  purpose  a  mixture  of  seventy  grains  of  starch  with  one 
ounce  of  glycerine,  heated  together  to  a  temperature  of  240Q  F. 
The  product  is  a  plastic  mass  well  suited  in  most  respects  for 
the  purpose,  but  has  been  objected  to  from  its  tendency  to  absorb 
moisture  and  become  fluid  by  long  exposure  to  the  atmosphere. 
The  inconvenience  arising  from  this  source,  however,  might  be 
easily  obviated  by  keeping  the  plasma  in  air-tight  jars,  and  dis- 
pensing it  when  necessary  in  wide-mouthed  bottles.  A  much 
more  serious  hindrance  to  its  general  use  is  the  fact  that  it  costs 
about  five  times  as  much  as  the  ordinary  adipose  basis  of  oint- 
ments. 
I  have  made  a  variety  of  experiments  with  "plasma,"  substi- 
tuting in  its  composition  for  the  common  wheat  starch  that  of 
arrow-root,  rice,  potato,  tous-les-mois,  etc.,  all  of  which  yield 
