4.  From  the  combination  of  the  primary  and  secondary  induction  coils
we  obtain  a  current  of  greater  tension,  but  which  still  acts  mildly  when
applied  externally.  Applied  internally,  however,  its  effects  are  far
greater  than  the  first  coil,  both  in  exciting  the  sensibility  and  contractility,
and  the  utmost  caution  must  be  exercised  in  its  use.  In  the  same  degree,
also,  it  acts  upon  the  vagina,  rectum,  bladder,  and  testes.  This  current
is  especially  applicable  in  the  treatment  of  enlargements  of  the  uterus  due
to  subinvolution,  but  is  of  little  or  no  value  when  the  enlargement  is  due
to  fibrous  tissue.  It  is  of  especial  value  in  post-partum  hemorrhage,  and
from  its  power  to  excite  the  sensibility  and  contractility  of  the  bladder  and
rectum  it  may  be  used  with  good  effect  when  these  organs  are  anaesthetic
or  suffer  from  diminished  or  lost  contractility.
5.  From  a  combination  of  the  first,  second,  and  third  induction  coils
we  obtain  the  maximum  of  power  to  excite  both  sensibility  and  contrac-
tility on  the  external  surface  of  the  body,  each  additional  coil,  provided  the
initial  force  or  voltage  is  not  increased,  simply  giving  a  decreasing  power
over  sensation  and  contraction.  Applied  internally,  however,  it  acts  far
less  powerfully  than  either  of  the  two  previously  named  currents;  but  in
the  ordinary  forms  of  paralysis  of  voluntary  muscles  it  will  more  readily
call  for  the  contractions  than  the  current  from  any  other  combination  of
coils.
