of  its  phenomena,  the  facts  and  investigations  are  clearer  and  more
decisive,  but  because  it  has  a  few,  though  very  few,  real  theories,
capable  of  affording  complete  previsions ;  a  thing  as  yet  impracti-
cable, except  in  a  general  manner,  with  living  bodies.  We  shall
have  occasion  to  notice  the  theory  of  proportions,  the  equivalent  of
which  is  not,  in  any  sense,  to  be  looked  for  in  physiology ._  We
must  remember,  while  estimating  the  comparative  imperfection  of
the  sciences,  that  the  importance  to  us  of  their  perfection  is  in  pro-
portion to  their  simplicity ;  our  available  means  being  always  found
to  correspond  with  our  reasonable  wants.  I  hope,  too,  that  this
severe  estimate  of  the  actual  state  of  each  science  will  stimulate
rather  than  discourage  the  student ;  for  it  is  more  gratifying  to  our
human  activity  to  conceive  of  the  sciences  as  susceptible  of  vast,
varied,  and  indeiinite  progress,  than  to  suppose  them  perfect,  and
therefore  stationary,  except  in  their  secondary  developments.
This  leads  us  to  consider  the  function  of  Chemistry  in  the  edu-
cation of  the  human  mind.
