AmMay^Sfm'}        History  of  Soap  in  Pharmacy.  215 
new  cut,  that  the  vertue  of  the  Spatula  may  be  mixed  with  the 
Plaister,  etc."  Those  who  have  access  to  medical  books  of  still  older 
dates  will  probably  find  in  them  similar  descriptions.  This  lead  soap, 
or  plaster,  as  it  was  generally  called,  entered  into  all  pharmacopoeias 
and  will  probably  remain  official  as  long  as  medicaments  are  used. 
The  method  of  making  it  is  based  on  the  same  principle  and  does 
not  differ  materially  in  the  various  countries;  litharge,  olive  oil  and 
water  are  boiled  till  saponification  takes  place.  The  lead  plaster 
forms  the  base  of  a  number  of  other  plasters  and  is  often  mixed  with 
a  soluble  soap;  for  instance,  in  a  London  Pharmacopoeia  of  1720,  a 
soap  plaster  is  described,  consisting  of  hard  soap  and  lead  plaster. 
When  the  manufacture  of  soap  became  a  prominent  industry, 
additions  of  various  natures  were  made,  first  to  impart  an  agreeable 
odor  and  make  the  soap  more  attractive  and  desirable  as  a  toilet 
article  ;  but  soon  other  ingredients  were  added  with  a  view  of  giving 
it  medicinal  virtues.    These  so-called  medicinal  soaps,  containing 
various  medicaments  that  were  otherwise  applied  in  the  form  of 
ointments  or  plasters,  as  sulphur,  tar,  carbolic  acid,  etc.,  were  in  the 
beginning  a  strictly  commercial  enterprise,  until  two  German  derma- 
tologists, Dr.  Unna,  of  Hamburg,  and  Dr.  Eickhoff,  of  Elberfeld, 
took  this  matter  up  in  1885  and  created  medicinal  soaps  on  strictly 
scientific  principles.    Both  wrote  a  series  of  articles  recommending 
soaps  in  place  of  plasters  and  setting  forth  their  advantages  very 
eloquently.    These  advantages  consist  in  the  fact  that  soaps,  as 
compared  with  plasters,  are  less  troublesome,  more  effective,  cleaner 
and  less  disagreeable,  absolutely  harmless  and  less  expensive.  Four 
different  methods  of  application  are  recommended  by  these  derma- 
tologists, viz.,  simple  washing ;  rubbing  dry  the  applied  foam  with 
woolen  cloths ;  allowing  the  foam  to  dry  on  the  skin ;  and,  finally, 
retaining  the  applied  foam  by  means  of  water-tight  dressings.  The 
third  method,  the  drying  of  the  foam  on  the  skin,  is  the  most  usual 
one.    While,  therefore,  the  soaps  thus  applied  will  also  exercise 
their  cleansing  properties,  they  are  principally  used  as  plasters,  and 
if  we  call  the  lead  plaster  an  insoluble  soap,  we  may  just  as  well  call 
these  medicated  soaps  soluble  plasters.    Both  Drs.  Unna  and  Eick- 
hoff lay  great  stress  on  the  necessity  of  preparing  a  good  soap-stock 
to  which  the  medication  is  added.    They  reject  the  cocoanut-oil 
soap,  which  is  largely  used  as  a  fine  toilet  soap,  on  account  of  its 
foaming  properties,  and  state  that  nine-tenths  of  the  skin  diseases, 
