Am.  Jour.  Phaim. 
Jan.,  1879 
Tests  for  Carbolic  Acid,  etc. 
33 
Absolute  cresylic  acid  is  miscible  with  Price's  glycerin  in  all  propor- 
tions. A  mixture  of  one  volume  of  glycerin  and  one  of  cresylic  acid 
is  completely  precipitated  by  one  volume  of  water. 
Creasote  is  insoluble  in  Price's  glycerin,  whether  it  be  added  in  the 
proportion  of  one,  two  or  three  volumes  for  one  of  creasote.  The 
sample  of  Price's  glycerin  used  for  the  above  experiments  was  found 
to  have  a  density  of  1*258. 
10.  Behavior  with  Collodion. — Absolute  carbolic  or  cresylic  acid,  when 
shaken  with  half  its  measure  of  Collodium,  B.  P.,  precipitates  the  nitro- 
cellulose in  a  transparent  gelatinous  form,  very  difficult  to  see.  It  is 
best  observed  by  inclining  the  tube  and  causing  the  liquid  to  flow  gently 
from  one  end  to  the  other.  Creasote  does  not  precipitate  the  nitro- 
cellulose from  collodion,  but  mixes  perfectlv  with  its  etherial  solution. 
Addition  of  much  creasote  to  a  mixture  of  collodion  and  carbolic  or 
cresylic  acid  causes  the  re-solution  of  the  precipitated  nitro-cellulose. 
11.  Reaction  with  Ferric  Chloride. — The  addition  of  one  drop  of  a  10 
percent,  aqueous  solution  of  ferric  chloride  to  15  cc.  of  an  aqueous  solu- 
tion of  cresylic  or  carbolic  acid  causes  a  permanent  violet-blue  colora- 
tion. When  creasote  is  similarly  tested  a  blue  color  results,  which 
almost  instantly  changes  to  green  and  brownish-yellow. 
Other  distinctive  tests  for  creasote  and  carbolic  acid  are  to  be  found 
in  the  books,  but  are  almost  worthless  in  practice.  Thus  the  reactions 
with  bromine,  sulphuric  acid  and  nitric  acid  are  far  too  much  alike  to 
be  of  service  for  distinguishing-  between  these  bodies.  It  has  been 
stated  that  creasote  differed  from  carbolic  acid  in  its  power  of  rotating 
a  ray  of  polarized  light.  I  redistilled  a  sample  of  Morson's  creasote 
to  obtain  it  colorless,  and  carefully  tried  this  test,  expecting  to  find  in 
it  a  possible  means  of  determining  the  creasote  in  a  mixture,  but  the 
rotating  powers  of  creasote  proved  so  exceedingly  weak  as  to  be  quite 
worthless  for  the  intended  purpose,  or  even  as  a  qualitative  test.  It  is, 
however,  quite  possible  that  different  samples  of  creasote  may  exhibit 
considerable  differences  in  this  respect,  but  if  so  the  test  is  valueless  for 
qualitative  purposes,  and  the  problem  is  not  so  much  to  detect  wood- 
creasote  as  to  recognize  an  admixture  of  the  coal-tar  acids.  I  am  also 
unable  to  confirm  the  statement  that  creasote  gives  a  solid  deposit  when 
kept  for  some  hours  at  the  temperature  of  boiling  water. 
I  have  not  obtained  satisfactory  results  by  the  reaction  of  an  alkaline 
solution  of  the  substances  with  hydrochloric  acid  and  pine-wood,  or 
