140  Adulteration  of  Soft  Soap.  {KmQ^;S^% 
Business  engagements  have  prevented  me  from  carrying  my  experi- 
ments further,  but  I  trust  sufficient  will  be  found  in  these  notes  to 
render  them  suggestive  to  the  medical  practitioner  and  pharmacist. — 
Pharm.  four,  and  Trans  ,  Jan.  18,  1879. 
THE  ADULTERATION  OF  SOFT  SOAP. 
The  "Manufacturers'  Review"  translates  from  the  French  of  M. 
Emile  Picard  the  following  note  on  the  adulteration  of  soft  soap: 
"One  hundred  parts  of  fatty  matter,  combined  with  soda  or  potash, 
yield  230  to  235  parts  of  pure  soft  soap,  containing  33*14  per  cent,  of 
water.  When  certain  adulterants  are  added  in  quantities  too  small 
to  affect  the  appearance  of  the  soap,  100  parts  of  grease  will  yield  320 
to  340  parts  of  what  would  be  a  good  commercial  article,  containing 
33  to  38  per  cent,  of  water.  The  same  quantity  of  grease  can  be 
made  to  produce  380  parts  of  soap  containing  as  much  as  52  per  cent, 
of  water.  The  adulterants  generally  used  are  clay,  resin,  fecula 
and  silicate  of  soda.  All  are  added  to  increase  the  yield  of  soap 
and  the  proportion  of  water  it  can  contain.  Clay  is  the  most  harm- 
less of  these  adulterants.  It  is  partly  dissolved  by  the  alkali,  but  makes 
the  soap  opaque,  and  is  easily  detected  by  its  insolubility  in  water. 
It  increases  the  amount  of  water  required  to  bring  the  soap  to  the 
proper  consistence,  but  is  not  otherwise  harmful.  It  is  less  and  less 
employed  every  day.  Resin  combines  with  alkali,  but  the  resulting 
compound  'possesses  none  of  the  emollient  qualities  of  fats.'  It 
retains  large  quantities  of  water,  but  alters  the  emollient  and  detergent 
power  of  the  soap,  and  makes  it  more  caustic  and  corrosive.  Soaps 
adulterated  with  resin  only  are  clear,  brilliant  and  transparent;  more 
soluble  in  water  than  pure  soap.  They  nearly  always  retain  a  slight 
odor  of  resin,  which  is  most  noticeable  when  the  soap  is  warmed. 
Their  color  is  often  redder  than  usual ;  they  attack  the  skin,  and  make 
linen  yellow.  Fecula  is  very  harmful,  especially  when  combined  with 
silicate  of  soda.  It  is  generally  employed  with  3  or  4  times  its  weight 
of  lye,  water  or  silicate  of  soda.  Soap  made  with  it  contains  an  excess 
of  alkali  and  a  very  large  quantity  of  water.  It  is  more  or  less  opaque 
as  the  proportion  of  starch  is  large  or  small;  it  is  easily  soluble  in 
water;  it  is  much  affected  by  changes  of  temperature,  and  its  deter- 
