ME.  J.  LISTEE  ON  THE  EAELT  STAGES  OE  INFLAMMATION. 
663 
The  precise  limitation  of  the  effect  produced  upon  the  blood  in  these  two  experiments 
to  the  area  covered  by  the  mustard,  showed  that  it  was  the  result  of  a direct  action  of 
the  irritant  either  upon  the  blood  that  flowed  beneath  it,  or  upon  the  tissues  of  the  part 
of  the  web  on  w'hich  it  lay,  the  blood  being  in  the  latter  case  affected  secondarily.  I 
made  several  experiments  to  determine  whether  the  adhesiveness  of  the  corpuscles  in 
blood  out  of  the  body  was  increased  by  contact  with,  or  vicinity  to  mustard,  placing 
minute  portions  of  it  between  plates  of  glass,  and  shedding  a drop  of  blood  from  a frog, 
so  that  it  might  run  in  betw^een  the  plates,  and  watching  the  result.  I could,  however, 
detect  no  evidence  of  such  change  in  the  corpuscles  as  I was  seeking ; whence  I inferred 
that  the  blood  had  been  only  affected  secondarily  to  the  tissues  in  the  two  mustard 
experiments. 
A careful  study  of  the  effects  produced  by  the  local  application  of  chloroform  to  the 
web,  confirmed  in  every  respect  the  conclusions  previously  arrived  at.  If,  while  the  eye 
of  the  observer  is  over  the  microscope,  a minute  drop  of  this  liquid  is  placed  with  a 
camel’s-hair  brush  upon  the  part  in  the  field  of  view,  it  evaporates  in  perhaps  two  or 
three  seconds ; and  if  the  web  be  dry,  the  time  of  its  disappearance  can  be  distinctly 
seen.  Yet  though  it  has  so  short  a time  to  act,  it  produces  so  powerful  an  effect  upon 
the  part,  that  the  red  corpuscles  immediately  experience  obstruction  to  their  progress, 
and  move  too  slowly  in  abnormal  numbers  through  the  capillaries,  which  perhaps  become 
entirely  clogged  with  them ; the  arteries  meanwhile  being  in  the  state  best  adapted  for 
easy  transmission  of  the  blood,  ^.  e.  full  dilatation.  In  one  such  experiment  I saw  a few 
corpuscles  sticking  together  in  a capillary  and  moving  wdth  difficulty,  from  evident  ten- 
dency to  adhere  to  its  parietes,  their  number  gradually  becoming  augmented  by  the 
adhesion  of  others  that  followed,  till  the  mass  grew  so  large  as  to  fill  the  vessel  for  some 
distance,  when  it  finally  stopped.  In  another  case,  the  circulation  being  perfectly 
natural  in  the  web,  and  the  corpuscles  moving  on  at  slight  intervals  with  no  tendency 
to  adhere,  on  a drop  of  chloroform  being  applied,  I saw  the  very  same  corpuscles 
instantly  become  checked  in  their  progress  by  sticking  to  each  other  and  to  the  capil- 
lary walls,  and  move  on  slowly  in  masses  with  considerable  intervals.  Thus  the  nature 
of  the  effect  produced  upon  the  red  corpuscles  of  the  blood  when  chloroform  is  applied 
to  the  web  is  the  same  as  that  caused  by  mustard,  viz.  an  abnormal  degree  of  adhesive- 
ness ; whereas  the  earliest  evidence  of  the  direct  action  of  chloroform  on  blood  out  of 
the  body  is  the  loss  of  the  adhesive  property  of  the  red  discs,  as  has  been  mentioned  in 
Section  I.*  That  the  effect  on  the  blood  within  the  vessels  of  a part  inflamed  by 
chloroform  is  secondary  to  a change  in  the  tissues  is  further  proved  by  the  circumstance, 
that  abnormal  accumulation  of  slowly  moving  corpuscles  may  last  for  hours  together 
stagnation  in  them.  This  I noticed  particularly  in  a case  in  which  caustic  ammonia  was  the  irritant  em- 
ployed. I would  remark,  however,  that  the  eye  is  apt  to  be  much  deceived  on  this  point  unless  the  micro- 
meter is  used.  Those  vessels  which  are  crammed  with  corpuscles,  being  of  dark  crimson  colour,  look  at  first 
sight  larger  than  others,  reaUy  of  the  same  size,  which  contain  the  normal  proportion  of  liquor  sanguinis, 
and  are  therefore  of  pale  tint. 
* See  p.  650. 
4 S 
MDCCCLVIII. 
