PHARMACEUTICAL  APPLICATION  OF  GLYCERINE.  65 
received  the  name  of  glyceroles.  Many  substances  are  more 
soluble  in  glycerine  than  in  water  or  alcohol.  When  an  aqueous 
or  spirituous  solution  is  applied  to  the  skin  it  rapidly  becomes 
dry ;  and  it  seems  reasonable  to  suppose  that  absorption  would 
then  be  greatly  retarded.  Glycerine  is  free  from  this  objection, 
and  its  peculiar  power  of  penetrating  the  pores  of  the  skin  ren- 
ders it  the  best  menstruum  for  many  substances.  Dr.  Richter, 
of  Vienna,  proposed,  in  1857,  a  caustic  application,  composed  of 
one  part  of  iodine,  two  of  iodide  of  potassium,  and  two  of  glyce- 
rine. I  am  surprised  that  this  in  various  states  of  dilution  has 
not  been  more  frequently  used  instead  of  the  tincture.  Glycerine 
dissolves  five  grains  of  iodine  to  the  ounce  without  the  addition 
of  iodide  of  potassium.  A  glycerole,  composed  of  tannin  one 
part,  glycerine  four  parts,  is  a  very  elegant  preparation,  and  is 
used  as  an  application  to  the  throat,  etc.,  per  se,  and  as  an  ad- 
dition to  gargles,  lotions,  injections,  etc.  One  ounce  of  glyce- 
rine dissolves  fifteen  grains  of  atropia,  and  seems  to  offer  some 
advantages  over  solutions  containing  acids  in  combination  with 
the  alkaloid  in  ophthalmic  surgery.  Borax  is  soluble  in  glyce- 
rine to  the  extent  of  fifty  per  cent.,  and  by  adding  this  solution 
to  tincture  of  myrrh,  we  obtain  a  «*  tincture  of  myrrh  with  bo- 
rax" superior  to  that  prepared  in  the  ordinary  manner.  The 
non-resinous  vegetable  extracts  are  soluble  in  glycerine,-— a  so- 
lution of  the  alcoholic  extract  of  Calabar  bean  has  lately  been 
used  with  success. 
In  the  other  class  of  medicaments,  viz.,  internal  remedies,  the 
use  of  glycerine  has  hitherto  been  more  limited.  Although  gly- 
ceroles have  often  been  brought  before  our  notice  as  substitutes 
for  syrups,  I  do  not  find  that  they  generally  possess  any  superi- 
ority. I  have  prepared  the  glycerole  of  iodide  of  iron  in  two 
ways : — first,  by  making  a  very  concentrated  solution  of  iodide 
of  iron  (about  equal  weights  of  water  and  iodine  with  iron  wire, 
q.  s.)  and  filtering  this  solution  into  glycerine;  and,  secondly, 
by  a  process  suggested  by  Mr.  James  C.  Leamy,  of  America,  in 
1848,  viz.,  to  make  a  more  dilute  solution  of  the  iodide,  mix 
with  the  glycerine,  and  evaporate  the  water  over  a  water-bath. 
The  former  is  nearly  colorless,  but  remains  so  only  for  a  few 
days.  The  latter  is  of  a  pale  straw  color,  and  appears  much 
less  liable  to  undergo  further  change.  A  glycerole  of  carbonate 
5 
