$60  Antiseptic  Materials.  {AmNoT;Sarm* 
It  sometimes  becomes  necessary  to  make  the  iodoform  gauze  10,  and 
even  25  per  cent,  in  strength,  in  which  case  the  benzin  method  cannot 
be  used,  and  recourse  is  then  had  to  the  older  method  of  Weir,  of 
iodoform  and  soap-suds,  modified  by  the  omission  of  mercuric  chlo- 
ride, which,  as  White  has  pointed  out,  results  in  mutual  decomposi- 
tion of  the  mercuric  chloride  and  the  soap.  To  use  this  method, 
take  the  iodoform  and  mix  it  with  ordinary  castile  soap-suds  in  the 
proportion  of  about  1  to  15;  pour  this  mixture  over  the  purified 
gauze  and  distribute  it  evenly  through  the  meshes  by  rubbing. 
When  dry,  wrap  in  paraffin-paper. 
Dr.  La  Place,  however,  prefers  to  use  a  pastry  mixture  of  iodo- 
form, ether,  alcohol  and  glycerin  to  spread  over  the  gauze  and 
exposed  to  the  air  until  all  the  alcohol  and  ether  have  volatilized. 
To  make  sublimated  gauze  the  following  formula  is  used  : 
Mercuric  chloride,  21^  gr. 
Ammonium  chloride,  21^  gr. 
Boiled  water,  6  pints. 
Purified  gauze,  100  oz.  av.  (about  54  yds.) 
Dissolve  the  chlorides  in  the  water,  immerse  the  gauze,  pre- 
viously cut  into  pieces  of  3  yards  ("  short  "J  or  6  yards  ("  long"), 
each,  in  length.  Express  moderately,  or  so  that  no  liquid  shall  be 
left.  Dry  in  a  clean,  dry  room,  upon  an  antiseptic  clothes-line. 
Remove,  wrap  in  parafifin-paper  and  keep  in  a  well-closed  container. 
It  is,  perhaps,  needless  to  say  that  in  all  these  operations  the  hands 
should  be  kept  germicidally  clean  with  "  bichloride  "  solution. 
The  product  contains  ^  of  one  per  cent,  of  the  active 
ingredient.  The  package  should  never  be  opened  until  about  to 
be  used,  and  then  only  by  the  physician,  and  who  uses  it  either  dry 
or  immerses  it  in  the  mercurial  solution,  before  applying  to  the 
wound. 
To  protect  the  edges  of  the  wound  from  irritation  by  the  anti- 
septic used,  it  is  usual  to  employ  a  piece  of  oiled  silk,  coated  with 
copal  varnish,  and  dusted  with  powdered  dextrine  (I  part),  pow- 
dered starch  (2  parts)  and  "  J^"  carbolic  acid  solution  (16  parts). 
This  is  the  so-called  "  Lister-protective."  The  dextrine  and  starch 
are  used  to  give  the  varnished  silk  a  surface,  which  will  allow  a  film 
of  water  to  evenly  spread  itself  over  it.  It  is  applied  along  the 
entire  length  of  the  wound,  leaving  free  the  ends  from  which  the 
drainage  tube  or  catgut  protrudes. 
