112 
Surgeons  Grit  Soap. 
{Am.  Jour.  Pharni. 
March,  1911. 
This  method  had  its  disadvantages,  however.  It  required  from 
five  to  six  weeks  to  become  firm  and  hard  enough  for  its  intended 
use.  It  also  was  somewhat  brittle.  This,  however,  was  overcome 
to  some  extent  by  using  potassium  hydroxide  instead  of  the  sodium 
hydroxide,  but  the  length  of  time  for  hardening  was  not  materially 
decreased.  Of  course,  this  could  have  been  overcome  by  using 
animal  fat  or  tallow,  but  it  is  not  always  practicable  or  possible 
to  obtain  this  readily. 
It  then  occurred  to  the  writer  that  stearic  acid  and  cottonseed 
oil  in  equal  proportions  might  produce  a  soap  that  would  harden 
at  once  or  in  much  less  time  than  the  method  described  above. 
Accordingly  some  experimentation  was  carried  on  with  this  fatty 
acid  and  cottonseed  oil  and  the  results  were  both  encouraging  and 
satisfactory.  So  much  so  in  fact,  that  the  following  formula  and 
method  of  procedure  was  finally  decided  upon  as  yielding  the  better 
product. 
Cottonseed  oil   500  c.c. 
Stearic  acid    500  Cms. 
Sodium  hydroxide   150  Cms. 
Alcohol    150  c.c. 
20  per  cent,  solution  sodium  chloride  q.s. 
Distilled  water  q.s. 
Powdered  pumice    300  Gms. 
Heat  the  cottonseed  oil  and  stearic  acid  until  the  acid  is  com- 
pletely dissolved.  Then  add  the  sodium  hydroxide,  dissolved  in 
a  litre  of  distilled  water,  and  heat  for  15  minutes  with  constant  stir- 
ring. Next  add  the  alcohol  and  stir  until  saponification  is  effected. 
This  is  noticed  by  the  mixture  becoming  homogeneous  in  a  few 
minutes.  Then  add  one  litre  of  a  20  per  cent,  solution  of  sodium 
chloride  and  stir  vigorously.  Allow  to  stand  until  the  soap  is  hard- 
ened ;  the  alkaline  liquid,  which  remains  at  the  bottom  of  the  con- 
tainer, is  then  drained  out  by  punching  a  hole  in  the  soapy  mass  on 
one  side.  It  is  then  washed  two  or  three  times  with  distilled  water, 
melted,  and  while  still  on  the  fire,  the  powdered  pumice  is  added, 
and  the  whole  thoroughly  incorporated.  While  still  hot  it  is  poured 
into  suitable  moulds.  In  twenty-four  hours  the  soap  is  sufficiently 
hard  enough  for  use. 
