ME.  J.  LISTEE  ON  THE  EAELY  STAGES  OF  INFLAMMATION. 
661 
From  the  facts  above  mentioned,  I became  convinced  that  no  satisfactory  explanation 
had  as  yet  been  given  of  the  obstruction  experienced  by  the  blood-corpuscles  in  the 
vessels  of  an  inflamed  part,  and  in  September  1856  I again  continued  the  investigation. 
Mustard  being  admitted  to  produce  inflammation  in  any  part  of  the  human  body  to 
which  it  is  apphed,  and  also  not  appearing  likely  to  act  by  way  of  exosmose,  I selected 
it  as  a suitable  irritant,  and  in  order  to  study  its  effects  accurately,  placed  a small  por- 
tion of  its  moistened  flour,  about  a line  in  diameter,  upon  the  middle  of  the  web  of  a 
large  frog  under  chloroform.  After  a while,  thinking  that  I saw  stagnation  in  a capil- 
lary just  at  the  margin  of  the  mustard,  I removed  the  latter  with  a camel’s-hair  brush, 
and  was  surprised  to  And  that  throughout  the  whole  area  on  which  it  had  lain,  the 
capillaries  were  crammed  with  either  stagnant  or  very  slowly  moving  red  corpuscles. 
The  limits  of  the  part  so  affected  corresponded  exactly  with  the  extent  of  the  applica- 
tion of  the  mustard,  although  the  capillaries  of  adjoining  parts  were  fed  and  drained  by 
the  same  arteries  and  veins. 
On  the  3rd  of  October  I made  another  similar  experiment,  selecting  a part  of  the  web 
where  a considerable  artery  divided  into  small  branches.  Before  applying  the  irritant, 
I had  ascertained  that  the  artery  running  through  the  area  measured  6^°  of  an  eyepiece 
micrometer*,  while  a large  vein  near  it  had  a diameter  of  12°.  About  half  a minute 
after  the  application  of  the  mustard,  when  I first  looked  through  the  microscope,  the 
arteries  of  the  web  generally  were  much  dilated,  and  the  flow,  which  had  before  been 
somewhat  languid,  was  rapid  in  all  its  capillaries.  The  opacity  of  the  mustard  prevented 
the  vessels  beneath  it  from  being  observed,  but  at  a short  distance  from  its  edge  the 
arteiy  measm’ed  10°  and  the  vein  14°.  In  a few  minutes  the  capillaries  seen  beneath 
advocated  by  a German  writer,  Fe.  Schttlee  of  Glarus  (Wiirzburg  Verhandlungen,  1854),  with  a very 
elaborate  series  of  difficult  experiments.  One  of  these,  however,  seems  almost  conclusive  against  his  theory. 
Having  injected  a solution  of  prussiate  of  potash  into  the  veins  of  a frog,  he  applied  sulphate  of  iron  to  the 
webs,  but  found  that  very  little  blue  colour  was  produced  until  the  epidermis  of  the  web  was  scraped  away, 
when  it  showed  itself  distinctly.  Considering  how  delicate  a test  prussian  blue  is  of  the  presence  of  a 
mixture  of  the  two  salts,  this  result  seems  to  show  that  there  is  far  from  being  the  same  tendency  to  mutual 
interchange  between  the  blood  in  the  capillaries  and  fluids  in  contact  with  the  surface  of  the  web,  as  there 
would  be  if  the  intervening  material  were  dead  animal  membrane  of  the  same  tenuity.  Were  the  disposi- 
tion to  exosmosis  and  endosmosis  such  as  is  assumed  in  the  above  explanation  of  stasis  from  a solution  of 
salt,  it  would  be  impossible  for  the  animal  to  live  long  either  in  water  or  on  dry  earth.  In  the  former  case 
the  blood  would  soon  become  diluted  from  imbibition,  and  in  the  latter  inspissated  from  evaporation.  But 
it  is  well  known  that  frogs  wiU  live  for  months  in  water  without  food,  and  I have  kept  them  for  weeks 
together  upon  dry  earth  at  a temperature  of  about  60°  Fahe.,  and  on  removing  from  the  webs  a layer  of 
dust  and  exfoliated  epidermis,  found  the  circulation  perfectly  healthy.  Since  the  reading  of  this  paper,  I 
have  seen  a remarkable  example  of  the  power  of  the  tissues  of  the  webs  to  resist  imbibition  of  water  in  an 
amputated  limb  with  the  blood  retained  in  the  vessels  by  a ligature.  Though  it  was  kept  in  wet  lint,  the 
blood  in  the  vessels  showed  no  indication  of  admixture  of  water  till  the  tenth  day,  and  then  only  in  those 
parts  of  the  web  in  which  the  arteries  and  pigment-ceUs  gave  evidence  that  they  had  lost  their  vitality. 
For  further  particulars  regarding  this  experiment  see  pages  618  and  640  of  this  volume. 
* The  micrometer  used  on  this  occasion  was  difierently  graduated  from  that  employed  in  the  warm  water 
experiments. 
