Thus,  where  a  grantor  of  land  warranted  the  same  to  be  free
of  incumbrances,  he  cannot  set  up  against  his  grantee  or
privies*'  a  mortgage  purchased  by  him  on  the  same  property;
nor  can  a  grantor  with  warranty  if  he  pays  the  mortgage  en-
force it  against  the  interest  of  his  grantee.""

SUBROGATION.
Subrogation  has  been  defined  as  "the  substitution  of  a  new
for  an  old  creditor,  or  in  its  more  general  sense,  the  fact  of
putting  by  transfer  a  person  in  the  place  of  another  or  a  thing
in  place  of  another  thing.  By  this  transfer  the  new  creditor
is  subrogated  to  all  the  rights  of  the  original  creditor."^""  The
doctrine  of  subrogation  is  not  founded  upon  contract  but  in
natural  justice  and  is  enforced  in  courts  of  equity.
The  doctrine  of  subrogation  finds  frequent  application  in
reference  to  mortgages.
""Ann  Arbor  Sav.  Bank  vs.  Webb,  56  Mich.,  377.
Smith  vs.  Roberts,  91  N.  Y.,  470.
Hanlon  vs.  Doherty,  109  Ind.,  37.
"Dutton  vs.  Ives,  5  Mich.,  515.
"See  Arnold  vs.  Green,  116  N.  Y.,  566.
"Hancock  vs.  E'leming,  103  Ind.,  533.
'"Knighton  vs.  Curry,  62  Ala.,  404.
