NOTE  ON  CARBOLIC  ACID,  ETC. 
265 
These  were  then  used  for  making  other  solutions,  from  which 
the  following  results  were  obtained. 
The  trials  upon  the  lichens  or  cryptogams  were  commenced 
with  solutions  containing  one-half  of  one  per  cent.,  or  five  parts 
in  the  thousand  (jo^o)-  ^  single  application  of  either  had  no 
visible  effect  upon  the  plants.  By  a  second  application  of  the 
same  solutions  to  the  same  places,  the  plants  were  completely 
killed  by  the  cresol,  but  not  visibly  affected  by  the  Phenol.  A 
third  and  fourth  application  of  the  solution  of  Phenol  to  the 
same  spot  produced  no  apparent  effect.  Solutions  containing 
one  per  cent,  were  next  used.  A  single  application  of  this 
promptly  and  entirely  destroyed  the  plant  in  the  case  of  the 
cresol,  but  had  little,  if  any,  effect  from  the  Phenol.  In  repeating 
the  trial,  it  appeared  possible  that  the  younger  and  more  feeble 
plants  were  killed  by  the  single  application  of  Phenol,  but  this 
was  not  certain.  A  second  application  to  the  same  places  killed 
almost  all  the  plants  when  applied  in  localities  where  they  were 
not  very  abundant  and  very  vigorous.  Occasional  patches  of 
the  strongest  plants  were,  however,  generally  left  after  the  second 
application  of  the  solution  of  Phenol  of  one  per  cent.  A  third 
application  of  this,  however,  cleaned  them  ail  off,  apparently  as 
clean  as  did  the  single  application  of  the  solution  of  cresol  of  the 
same  strength. 
Mixtures  of  the  two  solutions  were  then  tried,  with  results 
which  could  have  been  predicted  by  calculation  upon  those  above 
given. 
Then  the  natural  admixture  of  the  phenols  as  they  occur  in 
the  so-called  impure  carbolic  acid,  where  the  liquid  which  distils 
over  between  180°  C.  and  208°  C.  is  taken  altogether,  and  be- 
comes black  by  exposure  to  light  and  air,  80  or  90  per  cent, 
being  soluble  in  water.  This  impure  mixture  produced  very 
decidedly  stronger  effects  than  the  pure  Phenol  solution  of  the 
same  strength,  the  effects  being  estimated  to  be  nearly,  if  not 
quite,  double. 
These  results  seem  to  prove  that  the  crystallized  Phenol, 
or  crystallized  carbolic  acid,  is  by  far  the  least  effective  of  these 
two  chief  tar  products  as  an  azymotic.  But  at  the  same  time 
that  they  are  very  definite  in  regard  to  the  fact,  they  are  much 
