AFebmaryfib9iomj      Fat  Decomposition  and  Glycerin.  71 
showed  the  presence  of  peroxide  of  hydrogen.  Unfortunately  the 
author  only  gives  a  few  results  about  the  same  preparation  when 
kept  in  flint  glass  bottles  for  a  longer  period,  but  from  what  can 
be  learned  from  his  data  the  deterioration  of  the  peroxide  of  hydro- 
gen solution  is  usually  much  greater  when  kept  in  flint  glass  bottles 
than  when  kept  in  amber  colored  containers.  It  may  be  stated  at 
the  same  time  that  those  preparations,  in  which  the  percentage  of 
absolute  peroxide  of  hydrogen  was  reduced  to  two-thirds  of  their 
original  peroxide  strength  only,  possessed  a  rather  high  acidity. 
This  indicates  that  higher  acidity  tends  to  preserve  the  peroxide 
strength  of  peroxide  of  hydrogen  solutions. 
Since  writing  the  above,  a  paper  by  Prof.  Coblentz  on  this  subject 
has  been  presented  to  the  Revision  Committee  in  which  he  shows  that 
acetanilide  is  not  necessary  for  preserving  peroxide  solutions,  but 
also  holds  out  against  increasing  the  acidity  because  of  its  interfering 
with  the  usefulness  of  the  solution  in  surgical  work,  and  because 
manufacturers  should  use  less  alkaline  glass.  We  agree  with  him 
on  the  acetanilide  proposition,  but  we  think  he  is  wrong  on  the  other 
two,  for  even  if  the  amount  of  acid  allowed  by  the  present  U.S. P. 
is  doubled  as  we  suggest,  it  will  not  affect  the  most  sensitive  mucous 
surface  in  the  human  body.  And  as  to  glassware,  we  have  seen  that 
both  flint  and  amber  glass  possess  ample  alkalinity  to  soon  neutralize 
the  small  amount  of  free  acid  allowed  by  the  8th  Revision  require- 
ments, and  when  one  considers  the  increased  contact  with  the  glass 
affected  by  the  shaking  during  transportation,  and  this  must  be 
considered  by  the  Revision  Committee,  the  neutralization  of  the  free 
acid  is  greatly  augmented  as  compared  with  the  condition  presented 
by  mere  standing  contact  in  a  laboratory. 
PRACTICAL  APPLICATION  OF  THE  TWITCHELL  PROC- 
ESS OF  FAT  DECOMPOSITION  AND  RECOVERY 
OF  GLYCERIN. 
By  W.  J.  Warner. 
The  intention  of  this  article  is  to  state  the  advantages  of  the 
process  as  applied  to  refining  of  glycerin  and  its  advantages  and 
applicability  to  soap  making,  as  well  as  a  description  of  the  process 
as  "  worked  "  on  a  commercial  basis  in  a  plant  handling  50,000  lbs. 
of  fat  per  day. 
The  Twitchell  process  has  superseded  all  others  'in  the  candle 
