ABSORBING  POWER  OP  THE  ROOTS  OF  PLANTS. 
155 
Vessels  of  water  are  also  freely  at  hand  in  case  of  accident. 
Also  a  quantity  of  sand  is  strewed  in  a  layer  of  several  inches 
deep  beneath  the  racks  upon  which  the  frames  of  matches  are 
set  to  harden,  so  that  in  case  of  a  frame  of  matches  falling,  the 
flames  may  be  quickly  extinguished.  A  lotion,  composed  of 
olive  oil  and  lime  water,  is  exceedingly  useful  to  apply  to  the 
skin  in  cases  of  burning  by  phosphorus. 
(To  be  continued.) 
ABSORBING  POWER  OF  THE  ROOTS  OF  PLANTS. 
By  Dr.  Jessest. 
Dr.  Daubeny  has  established  that  different  species  of  plants, 
growing  in  the  same  soil,  take  up  therefrom  different  foods,  and 
certain  minerals  in  different  proportions.  This  selection,  it  will 
be  said,  is  made  through  "  vital  force," — a  convenient  phrase  for 
hiding  anything  that  you  cannot  or  have  not  inquired  into.  If 
we  went  down  to  the  elementary  composition  of  the  human  body, 
the  term  might  be  defined  as  meaning  the  formation  and  com- 
bination of  cells.  In  this  sense  it  corresponds  with,  and  has 
comparatively  the  same  range  as  the  term  "  crystallizing  force," 
as  regards  minerals.  The  force  which  puts  together  crystals,  and 
that  which  puts  together  cells,  and  forms  them  into  living  bodies, 
is  equally  an  unknown  force  ;  wTe  use  for  each  the  term  mention- 
ed. Taking  44  vital  force"  to  mean  the  formation  and  combination 
of  cells,  the  secretive  power  of  plants  was  thence  to  be  explain- 
ed. Some  ancient  philosophers  held  that  plants  desired  and  se- 
lected food  nearly  in  the  same  way  as  animals.  That  opinion 
was  long  ago  given  up  ;  but  where  is  the  difference  between  an- 
imals and  plants  ?  Men  and  animals  move  to  food  that  they  want ; 
plants  grow  for  it.  This  was  a  point  too  often  overlooked.  But 
animals  can  move  away  or  cease  to  take  food  when  satisfied  ; 
plants  advance  their  roots  amongst  their  food,  and  they  cannot 
use  the  same  parts  of  the  same  root  for  obtaining  that  root  a 
second  time.  They  have,  so  to  speak,  to  throw  cut  new  fibres 
every  time  they  want  food.  A  sound  rootlet  took  up  fluid,  whether 
nutritive  or  not,  in  a  manner  different  from  an  injured  one ; 
and  many  physiologists,  and  nearly  all  chemists,  have  experi- 
mented on  wounded  plants,  without  knowing  it,  owing  to  the 
delicate  handling  which  rootlets  require.  The  absorption  goes  on 
