By  the  assimilation  of  the  food,  I  mean  its  conversion  into
a  part  of  the  living  body.  This  is  effected  by  a  series  of
processes,  each  of  which  is  preparatory  to  that  which  follows
it.     Most  of  them  have  been  named.
Prehension  is  the  act  by  which  the  food  is  taken  into  the
mouth.  At  pasture  the  grass  is  seized  by  the  lips,  com-
pressed into  a  little  bundle,  and  placed  between  the  front
teeth,  which  separate  it  from  the  ground,  by  incision,  aided
by  a  sudden  jerk  of  the  head.  In  stable-feeding,  the  lips  and
teeth  are  used  in  nearly  the  same  way.  They  seize  the  food
and  place  it  within  reach  of  the  tongue,  but  they  produce  no
change  upon  it.  The  front  teeth  have  less  to  do  in  stable
than  in  field-feeding,  but  in  neither  case  do  they  masticate
the  food.  Prehension  of  fluids  is  performed  by  sucking.
The  lips  are  dipped  in  the  water,  and  the  cavity  of  the  mouth


ASSIMILATION    OF    THE    FOOD.  219

is  enlarged  by  depressing  the  tongue,  by  bringing  it  into  the
channel — the  space  between  the  sides  of  the  lower  jaw.
Prehension  may  be  difficult  or  interrupted  by  palsy  or  injury
of  the  lips,  soreness  of  the  tongue,  or  loss  of  the  front  teeth.
Colts  often  experience  difficulty  in  grazing  while  changing
the  teeth.  They  lose  flesh  for  a  while,  and,  if  they  lose  much,
some  rich  fluid  or  salt  boiled  food  may  be  given  till  the
mouth  get  well.  Horses  that  have  lost  one  or  two  of  their
fore-teeth  by  falls,  become  unfit  for  turning  out.  Those  that
have  lost  a  large  portion  of  the  tongue  can  not  empty  a  pail.
