292 
Carbolic  Acid  and  Creasote. 
(  Am.  .Tour.  Pharm. 
i     July  1,  1873. 
most  .common  impurities  found  in  carbolic  acid  is  coal-tar  oil.  This 
can  be  easily  detected  by  mixing  the  suspected  acid  with  about  twenty 
parts  of  water,  when  the  aeid  will  be  dissolved,  leaving  the  insoluble 
oil  floating  on  the  surface.  Pure  carbolic  acid  gives  a  pure  blue  color 
to  pine  wood  previously  treated  with  hydrochloric  acid;  a  green  color- 
indicates  anilin,  and  a  brown  pyrrhol.  It  ought  not  to  turn  brown  in 
the  air,  even  irr  the  presence  of  ammonia  ;  and  should  give,  with  sul- 
phate of  iron,  not  a  red  but  a  pure  lilac  color.  When  emersed  in  an 
aqueous  solution  of  chromic  acid  it  is  immediately  turned  black. 
There  have  been  a  greac  many  tests  given  to  distinguish  creasote 
from  carbolic  acid;  but  none  of  them  have  proved  satisfactory.  X 
give  below  some  of  the  principal  ones  now  used  for  that  purpose. 
With  three  or  four  volumes  of  a  saturated  aqueous  solution  of  ba- 
ryta, carbolic  acid  forms  a  clear  solution,  which,  after  standing,  gives 
no  deposit,  or  only  a  slight  pulverulent  one,  while  with  creasote  it 
forms  an  incomplete  cloudy  solution. 
With  an  alcoholic  solution  of  chloride  of  iron,  creasote  gives  a  green 
color,  carbolic  acid  a  brown  ;  but  with  art*  aqueous  solution  of  the 
same,  creasote  gives  no  reaction,  while  carbolic  acid  gives  a  blue 
color. 
According  to  Mr.  Morson,  pure  creasote  is  insoluble  in  glycerin,, 
while  carbolic  acid  forms  with  it  a  perfectly  clear  solution.  As  this 
test  has  been  the  subject  of  some  controversy  which  has  attracted  con- 
siderable attention,  I  have  made  a  few  experiments  with  it,  the  re- 
sults of  which  I  give  below. 
I  first  tried  the  common  creasote  of  commerce  with  an  equal  vol- 
ume of  glycerin,  and  found  it  to  be  readily  soluble;  Merck's  gave  the 
same  result,  but  Morson's  refused  to  dissolve  in  glycerin,  spec.  grav. 
1253,  even  after  three  or  four  volumes  had  been  added. 
I  then  carefully  added  carbolic  acid  to  a  mixture  of  Morson's  crea- 
sote and  glycerin,  and  found  that  upon  the  addition  of  twenty- three 
per  cent,  of  Calvert's  No.  2  acid  the  creasote  became  soluble,  forming 
a  perfectly  clear  solution  with  the  glycerin. 
Upon  the  addition  of  water  to  the  three  solutions  of  creasote,  they 
each  became  cloudy,  and  the  creasote  soon  separated  ;  while,  upon  a 
solution  of  carbolic  acid  in  glycerin,  water  had  no  effect  whatever. 
Some  time  ago,  while  preparing  a  catarrh  mixture  in  which  carbolic 
acid  is  used  in  conjunction  with  liquor  ammoniae  fortior,  alcohol  and 
"water,  1  found  that  upon  the  addition  of  the  ammonia  to  the  acid* 
