ME.  J.  LISTEE  ON  THE  EAELT  STAGES  OF  INFLAMMATION. 
701 
urethral  irritation  in  cases  where  renal  congestion  becomes  ultimately  established,  which 
seem  to  indicate  that  other  functions  as  well  as  arterial  contraction  may  be  primarily 
arrested  by  nervous  agency  in  the  early  stages  of  inflammation.  The  study  of  the 
pigmentary  system  of  the  frog  has  aflbrded  proof  that  other  tissues  besides  muscular 
fibre  are  under  the  control  of  the  nerves,  and  it  seems  not  unlikely  that  gland-cells  or 
other  forms  of  tissue  may,  like  nerve-cells,  be  reduced  to  a state  of  inactivity  by  excessive 
neiTOUs  action ; and  thus  we  seem  to  have  a clue  to  comprehending  what  at  first  appears 
anomalous,  that  prostration  of  the  vital  energies  of  the  part  actually  inflamed  may  be 
brought  about  by  unusually  great  activity  in  the  parts  of  the  nervous  system  specially 
concerned  with  it.  This,  however,  is  a wide  subject,  which  requires  further  investiga- 
tion. But  in  the  mean  time  we  may,  I think,  consider  as  satisfactorily  established  the 
fundamental  principle,  that  whenever  inflammatory  congestion,  or,  in  other  words,  that 
disturbance  of  the  circulation  which  is  truly  characteristic  of  inflammation,  exists  in  any 
degree,  the  tissues  of  the  affected  part  have  experienced  to  a proportionate  extent  a 
temporary  impairment  of  functional  activity  or  vital  energy. 
Explajvation  of  the  Plates. 
PLATE  XLVII. 
illustrates  the  anatomy  and  physiology  of  the  cutaneous  pigmentary  system  of  the  frog. 
Figs.  1 and  2 are  sketched  from  webs  of  different  feet  of  the  same  animal.  The  creature 
was  dark  when  it  was  killed,  but  one  of  the  legs  afterwards  underwent  the 
usual  post  mortem  change  to  a pale  colour,  and  such  was  its  state  when  fig.  2 
was  drawn.  The  other  limb  was  deprived  of  the  power  of  thus  altering  by 
immersion  for  half  a minute  in  chloroform ; and  fig.  1 shows  the  appearance 
of  the  colouring  matter  in  the  permanently  dark  condition  of  the  integument. 
Fig.  3 represents  two  chromatophorous  cells  with  the  pigment-granules  fully  diffused, 
the  animal  having  been  at  the  time  coal-black.  The  bodies  of  the  cells  are 
seen  to  be  pale,  containing  chiefly  colourless  fluid,  while  some  of  the  finest 
branches  of  the  offsets  are  quite  black,  in  consequence  of  the  dark  molecules 
being  closely  packed  together  in  them.  In  the  same  figure  a capillary  fully 
distended  with  blood-corpuscles  is  also  given. 
Fig.  4 represents  the  colouring  matter  in  the  same  two  cells  during  the  progress  of  the 
process  of  concentration.  The  dark  molecules  are  already  for  the  most  part 
collected  about  the  middle  of  the  body  of  each  cell ; but  in  the  very  centre 
of  each  cell  is  a pale  point,  where  the  granules  seem  not  yet  to  have  insinuated 
themselves  between  the  cell-wall  and  the  nucleus.  The  same  capillary  is  here 
seen  much  reduced  in  calibre. 
Fig.  5 shows  the  pigment  in  the  lower  of  the  two  cells,  concentration  being  still  further 
advanced. 
In  fig.  6 the  process  is  seen  to  be  almost  absolutely  completed,  the  molecules  being 
almost  all  of  them  aggregated  into  a black  circular  mass,  occupying  the  middle 
