The  two  paralyses  are  often,  but  not  always,  conjoined.  There  may  be
loss  of  reflex  action  to  light,  when  the  pupil  still  dilates  on  stimulation  of
the  skin.  The  pupils  are  often  small,  reduced  to  two,  one  and  a  half,  or
one  millimetre  in  diameter.  The  association  of  these  small  pupils  with
spinal  disease  was  noticed  before  the  more  significant  loss  of  the  light  reflex
was  discovered,  and  the  condition  was  called  "spinal  myosis."  But  the
pupils  are  not  always  small  ;  they  may  be  three,  four,  or  five  millimetres  in
diameter,  although  there  is  no  trace  of  reaction  to  light.  I  think  that  it  will
generally  be  found  that  when  the  pupils  are  not  small  the  skin  reflex  per-
sists, and  when  they  are  small  it  is  lost.  The  small  pupils  may  be  the  result
of  the  loss  of  tone  in  the  radiating  fibres,  accompanying  the  loss  of  the  skin
reflex.  In  cases  of  disease  of  the  third  nerve,  the  ciliary  muscle  is  paralyzed
as  well  as  the  iris.  When  the  reflex  loss  is  due  to  central  degeneration,  the
ciliary  muscle  is  usually  unaffected,  and  the  pupils  contract  during  accom-
modation. In  some  cases,  however,  there  is  also  cycloplegia.  All  the
internal  muscles  of  the  eyeball  are  then  paralyzed,  a  condition  to  which  we
shall  return.
*  This  has  not  yet  been  demonstrated,  but  hardly  admits  of  doubt,  because  the  loss  of  reflex
action  occurs  under  the  same  conditions  as  another  affection  to  be  presently  described — pro-
gressive paralysis  of  the  external  muscles — the  central  and  degenerative  nature  of  which  has
been  proved.
