60 
USE  OF  YELLOW  WAX  IN  OINTMENTS. 
In  reply  to  query  35th  the  writer,  to  whom  the  matter  was 
referred,  regrets  his  inability,  either  from  the  writings  of  others 
or  his  own  experiments,  to  say  with  certainty  to  what  principle 
yellow  wax  owes  its  preservative  properties ;  but  inclines  to  the 
belief  that  it  is  balsamic,  containing  benzoic  or  some  analogous 
acid. 
To  give  some  idea  of  the  length  of  time  for  which  the  con- 
servative power  of  yellow  wax  may  be  relied  on,  the  writer 
would  ask  attention  to  the  samples  of  cerates  which  accompany 
this  paper. 
No.  1.  Ceratum  adipis,  made  with  good  yellow  wax  January 
25th,  1867,  and  now  nearly  twenty  months  old,  is  in  a  good 
state  of  preservation. 
No.  2.  Ceratum  adipis,  made  with  Phillips'  strained  yellow 
wax,  March  11th,  1867,  now  about  eighteen  months  old,  is  in 
a  good  state  of  preservation. 
No.  3.  Ceratum  adipis  made  with  Phillips'  bleached  wax, 
March  11th,  1867,  now  about  eighteen  months  old,  bears  de- 
cided evidence  of  rancidity. 
These  samples  were  all  made  from  the  same  lot  of  lard,  have 
been  kept  partly  in  the  cellar  and  partly  on  the  shelves  in  the 
store,  exposed  to  the  same  temperature  that  the  cerates  of  the 
shop  are  required  to  stand  ;  generally  covered  to  keep  out  dust, 
but  always  together,  and  hence  under  precisely  the  same  cir- 
cumstances. 
The  writer  would  here  state  that  in  former  times,  when  using 
bleached  wax,  he  has  often  been  obliged  to  throw  away  portions 
of  simple  cerate  as  unfit  for  use  on  an  inflamed  surface,  but  that 
since  using  the  yellow  wax  (now  about  four  years)  no  such  occa- 
sion has  arisen. 
In  the  preparation  of  cold  cream,  which  is  required  to  be  par- 
ticularly white,  the  writer  continues  the  use  of  bleached  wax ; 
but  in  making  glycerin  cream  yellow  wax  is  used,  and,  while 
the  latter  keeps  perfectly  well,  the  former  sometimes  bears  evi- 
dence of  rancidity  perceptible  over  the  perfumed  waters  and 
essential  oils  in  its  composition. 
In  making  ceratum  plumbi  sub-acetatis,  or  Goulard's  cerate, 
which  is  perhaps  the  most  difficult  to  preserve  of  the  officinal  ce- 
