436  Reducing  Action  of  Vaseline  and  Paraffin.    {Amix?™£  im  m' 
INQUIRY  INTO  THE  REDUCING  ACTION  OF  VASELINE 
AND  PARAFFIN  ON  PERMANGANATE  OF 
POTASSIUM  AND  NITRATE  OF  SILVER 
WHEN  CONTAINED  IN  PILLS. 
By  Geo.  Smith,  F.  C.  S. 
Mr.  Martiudale  suggested,  in  a  letter  to  the  "Pharmaceutical  Jour- 
nal" for  January  13,  1883,  the  use  of  a  mixture  of  vaseline,  2  parts, 
paraffin  wax,  1  part,  and  kaolin,  3  parts,  as  a  convenient  and  uon- 
oxidizable  excipient  for  making  permanganate  of  potassium  into  pills. 
On  January  28,  1883,  some  pills  containing  2  grains  of  the  salt  in 
each,  and  3  grains  of  the  above  excipient,  were  made  by  the  writer, 
and  coated  at  the  same  time  with  a  solution  of  gum  sandarac  in  abso- 
lute alcohol,  as  recommended  by  Mr.  Martiudale.  Owing  to  other 
engagements  their  examination  was  not  attempted  till  June  26th  last. 
The  results  obtained  may  be  of  interest  to  those  who  may  have 
occasion  to  prescribe  or  dispense  this  remedy. 
As  a  preliminary,  on  boiling  one  of  the  pills  in  a  little  distilled 
water,  ample  evidence  of  the  presence  of  unreduced  permanganate  was 
obtained. 
Three  of  the  pills  containing  6  grains  of  the  salt  (==  *3888  gram) 
were  treated  with  distilled  water  (under  35°C),  until  all  soluble  per- 
manganate was  extracted.  The  resulting  cloudy  solution  was  made 
up  to  500  cc,  and  estimated  with  a  volumetric  solution  of  oxalic  acid 
containing  6 "3  grams  per  litre.  A  mean  of  three  estimations  made  on 
50  cc.  at  each  time,  proved  that  70  per  cent,  of  the  permanganate 
originally  present  in  the  pills  had  been  reduced. 
It  was  observed  that  the  sandarac  coating  reduced  the  permanganate 
as  fast  as  it  went  into  solution  at  first,  and  that  only  after  the  former 
was  completely  oxidized,  did  the  characteristic  deep  reddish  purple 
color  of  the  permanganate  begin  to  appear.  Obviously  this  reduction 
was  considerable,  and  to  avoid  it,  the  pills  were  carefully  scraped,  and 
the  coating  removed  as  completely  as  possible.  One  gram  of  the 
scraped  mass  (representing  *4  gram  of  the  permanganate)  was  broken 
down  and  treated  with  successive  portions  of  distilled  water  (under 
35°C.)  until  all  the  soluble  contents  were  removed,  and  the  resulting 
solution  allowed  to  settle  in  a  beaker.  When  moderately  clear,  it  was 
decanted  and  passed  through  glass-wool  into  a  flask,  the  residues 
