]VIE.  J.  LISTEE  ON  THE  EAELT  STAGES  OF  INFLAMMATION. 
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the  instrament,  arranged  the  fine  platinum  wire  extremities  of  the  poles  at  a short 
distance  from  one  another  at  opposite  sides  of  one  of  the  webs,  so  that  the  current  might 
pass  through  a part  in  the  field  of  view,  the  circulation  meanwhile  remaining  healthy. 
I now  completed  the  circuit  of  the  battery,  when  the  leg  became  instantly  drawn  up  by 
reflex  action ; yet  on  re-examination  of  the  web,  I found  that,  momentary  as  the  shock 
had  been,  the  part  through  which  it  had  passed  had  become  affected  with  intense 
inflammatory  congestion,  gradually  shading  off  towards  the  healthy  condition,  which 
existed  at  a little  distance.  After  about  a quarter  of  an  hour  resolution  of  the  con- 
fused mass  of  stagnant  corpuscles  occurred,  and  shortly  after  this  the  creature  regained 
the  power  of  voluntary  motion.  I afterwards  repeated  the  experiment,  both  upon  the 
same  animal  and  upon  another  specimen,  and  always  with  the  same  results ; and  I par- 
ticularly observ^ed  in  one  case  that  the  white  corpuscles  were  affected  with  great  adhe- 
siveness in  the  congested  region. 
"With  regard  to  the  manner  in  which  the  abnormal  condition  of  the  blood  was  brought 
about  in  these  cases,  it  has  been  afready  mentioned  in  Section  I.  that  the  galvanic  cur- 
rent produces  no  increase  of  the  adhesiveness  of  the  red  corpuscles  of  blood  outside  the 
body ; but  after  what  has  been  stated  in  the  last  Section,  the  reader  will  see  no  reason 
to  think  such  an  effect  likely.  It  may,  however,  seem  not  improbable  that  the  galvanic 
shock  might,  by  its  direct  action  upon  the  blood  within  the  vessels,  reduce  it  to  the 
same  condition  as  if  removed  from  the  body.  But  that  this  was  not  really  the  cause  of 
the  congestion,  was  clear  from  the  fact  that  in  the  parts  less  intensely  affected,  where  the 
corpuscles  still  moved  slowly  though  possessed  of  considerable  adhesiveness,  the  same 
condition  continued  long  after  all  the  blood  which  was  in  the  vessels  when  the  shock 
was  transmitted  had  passed  away.  In  this  case  therefore,  as  in  all  the  others  which  we 
have  considered,  the  blood  was  affected  secondarily  to  the  tissues.  This  being  established, 
the  natural  interpretation  of  these  experiments  appears  to  be,  that  the  portion  of  the 
web  affected  was,  as  it  were,  stunned  by  the  shock,  and  its  functions  suspended  like  those 
of  the  brain ; the  resolution  of  the  inflammation,  like  the  return  of  volition,  depending 
on  recovery  of  function  on  the  part  of  the  tissues  concerned. 
From  such  considerations  as  these,  it  appears  that  all  those  agents  which  produce  inflam- 
matory congestion  when  applied  to  the  web,  though  differing  widely  in  their  nature,  agree 
hi  ha\ing  a tendency  to  inflict  lesion  upon  the  tissues  and  impair  their  functional  activity. 
But  powerful  as  are  the  arguments  thus  obtained  by  inference,  it  is  very  desirable  to 
confii’m  them  by  direct  observation,  and  it  fortunately  happens  that  the  cutaneous  pig- 
mentary system  of  the  frog  is  a tissue  which  discharges  functions  very  apparent  to  the 
eye,  so  that  it  is  easy  to  trace  their  modifications  under  the  influence  of  irritation. 
In  the  first  experiment  with  mustard  described  in  the  last  section  (performed  Septem- 
ber 29th,  1856),  the  space  on  which  the  irritant  had  acted  presented  a very  striking 
difference  from  the  rest  of  the  web  in  the  appearance  of  the  pigment,  which  in  healthy 
parts  was  in  the  form  of  small  roundish  black  dots ; while  in  the  mustard  area,  and  accu- 
rately corresponding  to  the  extent  of  stagnation  in  the  capillaries,  each  spot  was  extended 
to  a stellate  figure. 
MDCCCLVIII.  4 U 
