f  Reichert  und  Du  Bois-Reymond's  Archiv,  1879.
40  SYMPTOMS.
interval,  the  local  contraction.  Burckliardt  has  found  that  the  latent  interval  for  a  skin
reflex  is  three  times  as  great  as  for  the  knee  jerk.  I  think  that  this  theory  of  reflex
irritability  and  local  stimulation  affords  a  full  explanation  of  all  the  relations  of  these
phenomena  to  the  central  nervous  system,  and  to  the  other  phenomena  of  disease,  and  it
is  the  only  theory  which  adequately  explains  them.
It  seems,  therefore,  that  the  term  "tendon  reflex"  is  altogether  inac-
curate. The  phenomena  are,  according  to  the  explanation  above  given,
dependent  on  a  "muscle  reflex"  irritability,  which  has  nothing  to  do
with  the  tendons.  If  we  wish  to  describe  them  by  a  general  term,  it  is
best  to  employ  one  which  does  not  involve  any  special  theory  of  their
nature.  They  may  be  termed  "tendon  muscular  phenomena,"  but  the
intervention  of  tendons  is  not  necessary  for  their  production ;  the  one
condition  which  all  have  in  common  is  that  passive  tension  is  essential
for  their  occurrence,  and  I  have  suggested*  that  they  be  termed  myotatic
contractions  (raruo?,  extended). f  The  irritability,  on  which  they  de-
pend, is  due  to  and  demonstrative  of  a  muscle  reflex  action  which  depends
on  the  spinal  cord.  It  is  highly  probable,  as  Tschirjew  suggested,  that
the  condition  on  which  the  myotatic  irritability  depends,  is  identical  with
muscular  "tone."  Since  the  experiments  of  Heidenhain,  it  has  been
generally  admitted  that  "tone"  depends  on  tension,  and  is  a  reflex
process.^  A  true  "tendon  reflex"  may  be  excited  by  pinching  the
tendon,  which  is  a  sensitive  structure  ;§  but  the  movement  produced  is  a
start  of  the  whole  limb,  precisely  such  as  results  from  a  pinch  of  the  skin.
