The  sight  is  generally  firom  the  first  seriously  impaired,  or
quite  destroyed,  the  iris  convex  anteriorly,  the  lens  and
humors  of  the  eye  slightly  cloudy,  the  pupil  dilated,  and,
on  looking  towards  the  bottom  of  the  eye,  there  will  appear


*  If  anj  surgeon  has  an  opportunity  of  seeinj^  and  treatxng  an
animal  affected  uith  melanosiii  only  in  a  slight  dejrree,  I  wr/oM  imgf^eM
the  propriety  of  his  eodeavouriDg  to  test  the  effect  of  the  ff^min$^
measures : — About  once  a  meek,  open  a  rein  in  f^/me  eonfeniein
situation,  and  remme,  accordinp:  to  the  sdze  of  the  animal,  Mrtenl
ounces  of  blood,  and  afterwards  inject  an  eqoal  qnantity  f4  ntua
holding  in  solution  a  little  of  the  carbonate  and  the  utunaul^A  mda,

3k


458

to  be  a  dull  dark  slate-coloured  body  situated  deeply  within
it. Hitherto  there  is  not  necessarily  present  any  material
uneasiness,  either  of  a  local  or  general  character,  nor  is
there  much,  perhaps  not  any,  superficial  redness. As
the  disease  advances  the  symptoms  put  on  a  more  serious
aspect,  for  then  the  posterior  chamber  is  filled  with  the
melanoid  mass,  the  lens  is  dislocated,  the  iris  compressed,
and  all  those  symptoms  are  produced,  which  tension  of
the  globe,  firom  whatever  cause  arising,  would  be  likely
to  excite. If  the  disease  continues,  and  the  patient  is  not
destroyed  by  the  extension  of  the  disease  in  other  parts,
(and  particularly  in  the  brain,)  the  cornea,  or  sclerotica,
will  either  give  way,  or  otherwise  it  may  be  necessary  to
make  an  opening  into  the  eye-ball,  to  relieve  the  intoler-
able anguish  which  sometimes  results  from  the  confinement
of  the  melanoid  growth. Before  the  external  tunics  give
way,  the  nature  of  the  disease  is  rendered  evident,  by  the
black  dingy  mass  behind  the  lens,  and  generally,  also,  by
a  peculiar  dark-brown  appearance  of  the  sclerotica. I  do
not  deem  it  necessary  to  pursue  this  part  of  my  subject
further,  for  the  symptoms  which  may  arise,  when  the
melanoid  mass  is  protruded  through  the  external  tunics,
will  be  modified  by  so  many  circumstances  which  are  not
peculiar  to  this  disease,  but  which  accompany  various
other  local  sources  of  irritation  arising  from  other  causes,
that  I  cannot  pretend  to  mention  them  in  detail. 