This  reflex  he  describes  as  ' '  a  contraction  of  the  myo-
cardium of  varying  duration. "  This  may  be  due  to  an
effect  sometimes  observed  by  stimulating  the  ac^cel-
erators,  i.e.,  to  ''strengthen  the  contraction  of  the
heart,"  which  may  estal)lish  an  equilibrium,  or  ac-
cepting Sajous'  views  the  action  may  be  due  to  a
secondary  effect  on  the  vagus  and  indirectly  on  the
adrenals.  This  effect  may  be  induced  by  an  inter-
rupted vibration  or  concussion  applied  to  the  spine
of  the  7th  cervical  vertebra,  or  as  demonstrated  by
the  author  by  interrupted  vibration  applied  between
the  transverse  processes  of  the  7th  cervical  and  1st
dorsal  vertebrae.  Abrains  observed  that  although
the  reflex  is  usually  more  noticeable  in  the  left  ven-
tricle, in  some  cases  it  is  confined  to  the  left  ventricle ;
but,  on  the  other  hand,  when  muscle  percussion  is
used  the  right  ventricle  only  contracts.  Normally
this  is  of  short  duration.
It  is  of  interest  to  note  the  effect  of  manual  fric-
tions on  "the  lower  cervical  nerves  of  the  sympathetic
system  as  observed  by  Cyriax.f

"As  a  general  rule  there  is  temporaiy  vaso-con-

•Abrams.    Spondylotherapy.    The  Heart  Keflex  of  Contraction,  page  201.
j  Cyriax.     Elements  of  Kellgren's  Manual  Treatment,  page  162.
HEAET,  BLOOD  VESSELS,  AND  DUCTLESS  GLANDS      193

striction  which  is  followed  by  a  certain  amount  of
vaso-dilatation  with  improved  and  slowed  cardiac
action."  Fainting  may  often  be  relieved  by  this
method.
