NOTE  ON  CARBOLIC  ACID,  ETC. 
263 
efficient  as  an  azymotic  than  the  pure  crystals  of  Phenol. 
Through  a  small  experience  of  two  years  or  more,  this  convic- 
tion has  been  strengthened  until  the  question  of  separating  these 
substances  and  rejecting  the  cresol  was  no  longer  in  doubt, 
though  still  not  proven ;  and  lately  a  series  of  experiments 
were  made  which  have  set  the  matter  at  rest  in  the  writer's 
mind,  and  are  now  to  be  briefly  referred  to. 
It  was  found,  as  expected,  that  a  very  dilute  solution  of  the 
impure  mixed  phenols  very  promptly  destroyed  and  detached 
the  cryptogamous  plants,  which  grew  in  the  form  of  a  green 
mildew  upon  the  brown  stone  and  drab  stone  fronts  and  areas  of 
residences  which  were  shaded  and  damp.  This  troublesome  and 
unsightly  defect  being  so  perfectly  and  so  easily  controlled  by 
the  creasote,  suggested  that  these  plants  would  be  an  easy 
practical  test  of  the  azymotic  efficacy  of  the  phenols  in  solutions 
of  various  strengths.  The  cryptogams,  as  they  grew  upon  a 
brick  pavement  in  a  damp  place,  were  made  the  subject  of  the 
experiments,  and  the  solutioas  were  applied  with  a  camel's  hair 
pencil.  In  a  preliminary  series  of  trials,  solutions  of  the  impure 
mixture,  of  various  strengths,  were  applied  without  apparent 
effect,  the  plants  looking  as  green  and  healthy  as  ever  on  the 
evening  of  the  day  of  the  application.  A  shower  came  in  the 
night,  however,  and  in  the  morning  the  bricks  were  bare  and 
clean  wherever  the  solutions  had  been  placed.  It  was  then 
remembered  that  the  destruction  of  the  chlorophyl  of  plants  was 
a  kind  of  fermentation,  and  it  was  argued  that  these  solutions 
killed  the  plants  by  their  azymotic  power,  but  by  their  antiseptic 
power  had  prevented  the  destruction  of  the  chlorophyl,  which  is 
the  common  evidence  of  death  in  the  green  parts  of  plants. 
The  plants  had  lost  their  hold  with  their  vitality,  and  the  rain 
drops  had  washed  them  away,  leaving  the  boundary  lines  of 
contact  of  the  solution  as  sharp  as  though  made  with  a  knife, 
though  quite  invisible  the  evening  before  after  the  solutions  had 
dried  off. 
This  little  observation  shows  the  need  for  a  new  word  to  ex- 
press the  peculiar  power  of  this  substance  over  vitality,  and 
which  might  subserve  the  purposes  of  convenience  and  accuracy 
of  expression  now  when  this  peculiar  and  comparatively  new 
