Mli.  J.  LISTEE  ON  THE  EAELT  STAGES  OF  INFLAMMATION. 
649 
the  discs  stick  together  by  any  parts  that  happen  to  come  first  in  contact,  and  retain 
that  position  more  or  less,  so  that  the  result  is  the  formation,  not  of  rouleaux,  but  of 
irregular  confused  masses.  The  most  striking  example  which  I have  seen  of  this  was 
presented  by  the  blood  of  a bat,  which  had  hved  some  days  after  having  been  severely 
wounded.  In  that  case,  chains  of  red  discs  might  be  seen  adhering  firmly  by  their  edges, 
notwithstanding  considerable  force  of  traction  operating  upon  them,  and  before  they  at 
last  gave  way,  tail-like  processes  of  considerable  length  were  drawn  out  between  every 
pah  of  corpuscles,  indicating  that  they  were  very  adhesive.  These  facts  seem  sufficient 
proof  of  the  correctness  of  the  view  above  expressed  regarding  the  cause  of  the  rou- 
leaux. 
The  adhesiveness  of  the  red  corpuscles  does  not  appear  to  be  a vital  property.  When 
the  fibrine  has  been  removed  from  a drop  of  blood  during  the  progress  of  coagulation, 
the  rouleaux  will  form  again,  after  being  broken  up,  as  many  times  as  the  experiment 
is  repeated,  until  the  blood  becomes  thick  from  dryness  ; and  if  evaporation  be  pre- 
vented by  Canada  balsam  placed  round  the  plate  of  thin  glass,  tvith  suitable  precaution 
against  the  approximation  of  the  two  plates,  the  rouleaux  will  remain  perfect  for  several 
days  {e.  g.  fomdeen  in  one  experiment  of  the  kind),  after  which  the  very  slow  che- 
mical action  of  the  balsam  upon  the  blood  gradually  renders  it  confusedly  red  and 
opaque.  Gum  mixed  with  blood  seems  to  preserve  it,  hke  a pickle,  from  decomposition 
for  a very  considerable  period ; and  if  a piece  of  wet  lint  be  suspended  above  such  a 
specimen  so  as  to  prevent  evaporation,  the  corpuscles  will  retain  their  adhesiveness  for 
a long  time  [e.  g.  twenty-four  days  in  one  instance),  until  the  water  communicated  to 
the  mixture  by  the  artificially  damp  atmosphere  gradually  renders  them  non -adhesive. 
These  experiments  were  made  in  winter,  when  the  low  temperature  prevents  rapid 
decomposition ; but  it  appears  unlikely  that  even  at  that  period  of  the  year  a part  of 
the  human  body  should  retain  any  \ital  properties  after  having  been  left  three  and  a 
half  weeks  mixed  with  strong  gum,  which,  it  is  to  be  observed,  alters  very  much  the 
form  and  appearance  of  the  corpuscles. 
Both  in  man  and  in  the  fr’og  the  white  corpuscles  also  are  found  aggregated  together 
more  or  less  in  a drop  of  blood  examined  microscopically,  and  indeed  they  adhere  much 
more  closely  than  the  red  ones  both  to  the  glass  and  to  one  another ; but  as  they  are  not 
disc-shaped,  but  globular,  they  do  not  become  grouped  into  rouleaux,  but  into  irregular 
masses,  which,  in  consequence  of  their  colourless  and  transparent  character,  are  apt  to 
pass  unnoticed,  or  to  be  mistaken  for  masses  of  coagulated  fibrine.  If  a portion  of 
blood  be  allowed  to  run  in  between  two  plates  of  glass  nearly  in  contact  with  one 
another,  the  white  corpuscles  will  be  found  sticking  together  near  the  edge  of  the  glass 
at  which  the  blood  entered,  the  blood  having  been  as  it  were  filtered  of  white  cor- 
puscles as  it  passed  on ; and  this  is  not  due  to  the  greater  size  of  the  colourless  corpuscles 
than  the  red,  for  I have  seen  it  occur  with  frog’s  blood  when  there  was  room  enough 
between  the  yfrates  for  the  red  corpuscles  to  lie  edgewise,  their  transverse  dimensions 
being  greater  than  the  diameter  of  a white  corpuscle. 
4q2 
