Salicylic  Acid, 
/  Am.  Jour.  Pharm. 
1     July,  1876. 
seems  to  be  a  concentrated  solution  which  will  bear  dilution  with  water 
to  any  extent.  Recently,  a  writer  in  the  "  Druggists'  Circular,"  has 
recommended  the  use  of  sodium  biborate  and  glycerin  in  the  propor- 
tions of  1  part  each  of  salicylic  acid  and  the  biborate  to  16  parts  glyce- 
rin. This  gives  a  solution  containing  about  6  per  cent,  salicylic  acid, 
and  is  freely  miscible  with  water  in  all  proportions. 
While  recently  experimenting  with  this  formula,  it  occurred  to  the 
writer  that  probably  a  still  stronger  and  more  concentrated  solution 
might  be  obtained  by  some  slight  modifications.  After  several  experi- 
ments the  following  formula  was  adduced  : 
Acid,  salicylic,  pur.,       .....  gij 
Sodii  biborat.,  ....... 
Glycerinas,    .        .       .       .       .       .       »      q  s. 
Mix  the  acid  and  borax  with  f3iv  glycerin,  heat  gently  until  dissolved, 
then  add  q.  s.  glycerin  to  make  the  measure  f^i.  This  solution  con- 
tains 25  per  cent,  salicylic  acid,  and  can  be  diluted  with  either  glycerin, 
alcohol  or  water  to  any  degree  desired. 
The  advantages  of  a  concentrated  solution  of  this  description  can 
scarcely  be  overestimated,  as  it  affords  a  very  convenient  mode  of  both 
prescribing  and  dispensing  salicylic  acid. 
June  20th ,  1876 
ON  SALICYLIC  ACID. 
BY  CHARLES  BECKER. 
The  addition  of  the  phosphates  of  ammonium  or  sodium  has  been 
recommended  to  increase  the  solubility  of  salicylic  acid  in  water,  but 
these  agents  really  amount  to  but  very  little,  as  a  solvent  of  1  part  of 
the  acid  in  three  of  either  phosphate,  and  fifty  parts  (by  weight)  of 
water  throws  down  a  precipitate  in  less  than  twenty-four  hours.  An 
addition  of  two  parts  of  sulphite  of  sodium  to  one  of  salicylic  acid,  in 
fifty  parts  of  water,  precipitates  in  a  few  hours.  Borax  in  the  propor- 
tion of  two  parts  to  one  of  salicylic  acid,  and  fifty  of  water,  precipitates 
slightly  after  twenty-four  hours  ;  a  solution  of  one  part  each  of  salicylic 
acid  and  borax,  in  five  parts  of  glycerin  and  twenty-five  of  water,  is 
permanent ;  while  the  same  proportion  of  borax,  acid  and  glycerin,  in 
fifty  parts  of  water,  will  precipitate  after  twenty-four  hours.  A  solu- 
tion of  one  part  of  acid  to  two  of  borax,  in  twelve  parts  of  glycerin, 
made  with  heat,  is  permanent ;  but  when  one  part  of  this  solution  is 
