214  Liquor  Cresolis  Compo situs,  U.S. P.     { Am  May?i908arm' 
Perfect  solubility,  although  very  desirable,  is  by  no  means  the 
most  important  point  in  this  preparation.  Our  first  aim  must  be  to 
produce  a  preparation  of  maximum  efficiency  as  an  antise  ptic  and 
germicide  with  the  minimum  amount  of  caustic  or  irritating  prop- 
erties. As  will  be  seen  from  the  following  tests,  the  reduction  of 
the  quantity  of  soap  in  the  preparation  renders  it  excessively  irri- 
tating. The  tests  with  substances  and  preparations  mentioned 
below  were  carried  out  in  the  following  manner : 
One  drop  of  each  was  spread  over  approximately  one  square  inch 
of  skin  on  the  human  arm,  and  the  action  noticed  and  recorded  at 
intervals.  All  of  them  were  tried  on  several  persons,  so  as  to 
obtain  fairly  reliable  results.  Numbers  I  to  6  inclusive  produced 
escharotic  action  in  from  one  (phenol)  to  twenty  (Liquor  cresolis 
comp.  containing  16  per  cent,  of  soap  and  50  per  cent,  of  cresol) 
minutes.  Numbers  7  to  16  inclusive  only  reddened  the  skin,  while 
the  remainder  produced  no  noticeable  irritation  ;  these  were  com- 
pared as  to  their  relative  irritating  properties,  by  noticing  the  effect 
of  diluted  solutions  on  mucous  membranes.  They  are  given  in  the 
order  of  their  action,  beginning  with  the  most  escharotic. 
(1)  Phenol. 
(2)  Liquor  cresolis  compositus,- 8  per  cent,  soap,  50  per  cent, 
cresol. 
(3)  Paracresol. 
(4)  Cresol  U.  S.  P. 
(5)  Metacresol. 
(6)  Liquor  cresolis  compositus,  16  per  cent,  soap,  50  per  cent, 
cresol. 
(7)  Orthocresol. 
(8)  Cresol  U.  S.  P.,  alcohol,  equal  volumes. 
(9)  Liquor  cresolis  compositus,  24  per  cent,  soap,  50  per  cent, 
cresol. 
(10)  Seven  per  cent,  solution  of  phenol. 
(11)  Liquor  cresolis  compositus,  32  percent,  soap,  50  per  cent, 
cresol. 
(12)  Five  per  cent,  solution  of  phenol. 
(13)  Cresol  U.  S.  P.  2  parts,  alcohol  1  part,  glycerin  I  part. 
(14)  Liquor  cresolis  compositus  from  paracresol. 
(15)  Potassium  cresolate  sol.  (rep.  50  per  cent,  cresol). 
(16)  Liquor  cresolis  compositus  (incompletely  saponified). 
