^l^itjs™'}      The  Preparation  of  Sapo  Viridis.  397 
salicylate  is  formed,  and  very  strong  vapors  of  acetic  acid  are  evolved 
in  the  cold. 
Salicylic  acid  forms  three  salts  with  ferric  oxide,  a  normal  salt,  a 
basic  salt  and  a  so-called  ferric  ferro-salicylate. 
Compare  the  author's  paper  on  the  "Application  of  these  salts  to 
acidimetry  and  alkalimetry." — Wien.  Sitzungsber.^  lxxiv.  49,  from  Jour* 
Chem.  Soc,  March,  p.  224. 
THE  PREPARATION  OF  SAPO  VIRIDIS. 
By  E.  B.  Shuttleworth. 
During  the  past  two  or  three  years  several  formulae  have  been  pub- 
lished for  the  preparation  of  substitutes  for  green  soap,  but,  as  far  as 
my  own  experience  goes,  none  of  them  give  satisfactory  results.  A  so- 
called  green  soap,  used  until  lately  in  the  hospitals  here,  consisted  of  a 
partly  saponified,  yellowish  and  almost  odorless  mass,  formed  by  boiling 
together,  for  a  considerable  time,  a  mixture  of  2  parts  spermaceti  and 
I  of  solution  of  potash,  sp.  gr.  1*300.  Another  formula,  much  nearer 
the  mark,  directs  the  saponification  of  1  part  of  linseed  oil  by  an  equal 
weight  of  solution  of  potash,  sp.  gr.  1*130.  The  quantity  of  potash  is,, 
however,  insufficient,  and  as  one  of  the  therapeutical  essentials  of  the 
preparation  is  that  the  alkali  be  in  slight  excess,  the  effects  realized  are 
not  always  those  which  are  anticipated.  Lastly,  we  have  a  recipe, 
given  in  a  short  paper  by  Mr.  Herman  Betz,  in  the  "Amer.  Journ. 
Pharm.,"  from  which  it  has  been  reproduced  in  most  of  the  pharma- 
ceutical serial  publications  of  the  time. 
On  first  looking  over  this  formula,  I  did  not  notice  that  the  solution 
of  potash — presumably  that  of  the  U.  S.  P. — is  ordered  in  only  about 
one-third  the  quantity  required  for  saponification,  and  consequently  any 
attempt  to  follow  this  recipe  strictly  would  certainly  end  in  failure  and 
disappointment.  Druggists  are  not  always  skilled  soap-boilers,  and 
though  the  operation  is  simple  it  requires  considerable  experience.  I 
have,  therefore,  taken  the  liberty  of  correcting  this  error,  and  also  beg 
to  add  a  few  plain  and  practical  directions  regarding  the  process. 
In  a  clean  pot  or  dish,  preferably  of  iron  or  copper,  and  capable  of 
containing  at  least  three  times  the  quantity,  put  1  part,  by  weight,  of 
linseed  oil,  heat  gently  and  add  in  two  portions,  3  parts  in  all,  by 
measure,  of  liquor  potassae,  U.  S.  P.  or  B.  P.,  providing  either  come 
