54 
CONSTITUTION  OF  COAL-TAR  CREOSOTE. 
Flence  the  author  concludes,  that  this  acid  is  produced  from 
one  of  the  insoluble  matters  of  the  wood,  from  some  substance 
which  no  doubt  stands  in  near  relation  to  tannic  acids,  and 
which  is  perhaps  produced  from  this  in  the  course  of  vegetation, 
or,  on  the  contrary,  may  furnish  the  material  for  its  formation. 
Starch  and  cellulose  are  not  the  sources  of  this  pyrogenous 
acid,  for  straw,  paper,  and  starch  do  not  furnish  it  on  distilla- 
tion. It  appears,  therefore,  that  one  of  the  substances  incrust- 
ing  wood  furnishes  the  material  for  this  pyrogenous  acid. 
A  more  extended  investigation  of  the  distribution  of  the  tan- 
nic acids  in  the  vegetable  kingdom,  which  is  not  yet  completed, 
has  already  led  the  author  to  the  result  that  the  tannic  acids  ex- 
ist in  perennial,  but  not  in  other  plants,  which  certainly  indi- 
cates a  close  connexion  with  the  formation  of  wood.  Potentilla 
tormentilla  and  Solanum  dulcamara,  which  are  perennial  plants, 
contain  tannin  ;  the  annual  species,  Potentilla  anserina  and  So- 
lanum  tuberosum,  contain  none. — Chem.  Gaz.,  from  Buchners 
Neues  Repertorium,  iii.  p.  74. 
ON  THE  CONSTITUTION  OF  COAL-TAR  CREOSOTE. 
By  Prof.  Williamson. 
For  some  years  past  it  has  been  a  debated  question  among  che- 
mists, whether  the  peculiar  body  orginally  described  by  Reichen- 
bach  as  creosote,  and  subsequently  analysed  by  Ettling  and  others, 
has  any  real  existence,  or  whether  the  properties  which  were  attri- 
buted to  it  are  not  to  be  more  correctly  ascribed  to  the  hydrate  of 
phenyle,  which  can  be  obtained  in  a  state  of  great  purity  from  at 
least  one  sort  of  commercial  creosote  by  mere  distillation,  and 
which  possesses  in  an  eminent  degree  the  antiseptic  properties  for 
which  creosote  is  remarkable. 
With  a  view  of  obtaining  some  light  on  this  question, Mr,  Fairlie 
undertook,  in  the  laboratory  of  University  College,  an  investigation 
of  the  portions  of  coal-tar  creosote  which  boil  higher  than  the  hy- 
drate of  phenyle.  The  result  of  his  experiments  has  been  to  show 
that  a  body  homologous  to  hydrate  of  phenyle  may  be  obtained 
from  the  crude  creosote,  in  fact  the  next  term  of  the  series  above 
hydrate  of  phenyle  itself.    Some  qualities  of  commercial  creosote 
