544 
A frican  Copaiba. 
( Am.  Jour.  Pharrru 
t       Nov.,  1893. 
not  take  place  in  the  dark,  nor  under  red  glass ;  it  is  the  work  of 
the  more  refrangible  rays  of  light  only. 
As  has  often  been  observed,  sublimed  phenol  does  not  redden  as 
rapidly  as  the  distilled  product ;  in  fact,  according  to  Bidet,  it  does 
not  color  at  all  on  exposure  when  thus  purified.  This,  however,  is 
not  the  case,  the  sublimed  product  becomes  colored  quite  as  quickly 
as  distilled  phenol  when  in  solution,  and  that  it  is  slower  in  turning 
pink  when  in  the  solid  state  is  due  to  the  fact  that  the  crystals 
obtained  by  sublimation  are  less  hygroscopic  than  the  distilled  pro- 
duct. In  absence  of  moisture,  under  all  conditions,  no  coloration 
ensues ;  hence  the  appearance  of  the  color  in  those  portions  of  the 
sample  which  have  become  partially  liquefied.  Phenol  placed  in 
vacuo  can  be  exposed  to  light  for  months  without  becoming  red,, 
nor  does  it  color  either  in  presence  of  moisture  when  air  is  absent, 
or  in  presence  of  air  when  perfectly  dry.  Both  air  and  moisture  are 
necessary  for  the  coloration  to  take  place. 
The  similarity  between  the  colored  products  formed  by  the  action 
of  moist  air  and  phenol  and  that  produced  by  hydrogen  peroxide 
naturally  led  one  to  look  to  the  latter  as  the  real  factor  in  the 
oxidation.  That  such  is  the  case  has  been  conclusively  shown  by 
Dr.  A.  Richardson,  who  has  succeeded  in  detecting  the  presence  of 
hydrogen  peroxide  in  reddened  phenol,  both  by  the  chromic  acid 
and  by  the  titanic  acid  test. 
This  same  color  is  produced,  together  with  a  complexity  of  other 
substances,  when  phenol  is  electrolyzed  in  acid  solution.  The  nature 
of  the  colored  product  formed  is  still  under  investigation,  and  not 
until  the  coloring-matter  itself  is  more  completely  studied  can  any 
conclusion  be  drawn  as  to  the  course  of  the  oxidation. 
AFRICAN  COPAIBA.1  ^ 
BY  John  C.  Umney,  F.C.S. 
I  have  already  called  attention  to  the  principal  general  characters 
of  this  oleoresin  as  imported  from  the  Niger  basin  in  a  preliminary 
note  (A.  J.  P.,  1892,  p.  33),  and  compared  two  samples  from  that 
source  with  specimens  of  South  American  origin.  The  results  may 
be  briefly  summarized  thus : 
1  Read  at  British  Pharmaceutical  Conference,  Nottingham,  August  16,  1893. 
through  Pharm.  Jour.  Trans.,  September  9,  1893,  p.  215. 
