Am.  Jour,  riiarm.  1 
September,  1911.  J 
Standard  Surgical  Dressings. 
419 
Purified  cotton  should  contain  no  more  than  a  very  small  quan- 
tity, if  any,  of  visible  impurities,  and  on  combustion  of  five  grammes 
or  more  should  not  leave  more  than  0.2  per  cent,  of  ash. 
Ten  grammes  of  purified  cotton  are  saturated  with  100  c.c. 
neutral  distilled  water,  the  water  pressed  out  and  divided  into  two 
portions,  each  of  which  is  placed  in  a  white  porcelain  dish.  To 
one  portion  is  added  3  drops  phenolphthalein  T.  S.,  and  to  the 
other  portion  one  drop  methyl  orange  T.  S.  Neither  portion  should 
develop  a  pink  color  (absence  of  acid  or  alkaU). 
If  20  grammes  be  extracted  in  a  narrow  percolator  with  ether 
until  300  c.c.  percolate  is  secured,  the  percolate  should  on  evaporation 
to  dryness  in  a  tared  beaker  leave  a  residue  of  not  more  than 
0.5  per  cent,  of  the  weight  of  cotton  used  (limit  of  fatty  matter). 
A  blank  test  should  be  made  with  an  equal  quantity  of  the  ether  used. 
If  20  grammes  be  extracted  in  a  narrow  percolator  with  alcohol 
until  200  c.c.  percolate  is  secured,  the  percolate  should  not  be  of 
a  blue  or  green  tint  (absence  of  dyes)  and  on  evaporation  to  dryness 
in  a  tared  beaker  the  residue  should  amount  to  not  more  than  0.5 
per  cent,  of  the  cotton  used  (limit  of  resins  and  soap).  A  blank 
test  should  be  made  with  an  equal  quantity  of  the  alcohol  used. 
If  20  grammes  be  extracted  in  a  narrow  percolator  with  hot 
distilled  water  (80°  to  90°  C.)  until  200  percolate  is  secured,  the 
percolate  should  not  be  clouded  (absence  of  soap),  and  on  evapora- 
tion to  dryness  in  a  tared  beaker  the  residue  should  amount  to  not 
more  than  0.2  per  cent,  of  the  weight  of  cotton  used  (limit  of  soluble 
salts).  A  blank  test  should  be  made  with  an  equal  quantity  of  the 
water  used. 
Gauze  cloth,  otherwise  known  as  surgical  gauze,  came  into  use 
as  a  wound  dressing  with  Listerism.  Lister  first  applied  lint,  after- 
wards what  was  known  as  cheese  cloth,  which  by  evolution,  was 
converted  into  surgical  gauze,  and  finally  a  combination  of  absorbent 
gauze  and  cotton.  The  tendency  of  modern  surgical  technic  has 
been  to  simplify  dressings.  All  other  substances  have  to  a .  large 
extent  been  abandoned  and  gauze  made  to  constitute  almost  solely 
the  dressing  material. 
A  good  quality  gauze  has  numerous  and  obvious  advantages  over 
any  other  material  for  this  purpose.  It  is  highly  absorbent,  pliable, 
with  an  open  texture  that  is  firm  and  strong,  it  is  free  from  the 
loose  fibres  and  irritating  particles  found  in  unspun  cotton.  It 
is  cool,  light,  and  readily  shaped  into  required  forms. 
