It  has  long  been  known  that  when  healthy  blood  is  received  on  a
glass  plate,  and  immediately  examined  with  the  microscope,  the  cor-
puscles may  be  seen,  in  about  half-a-minute,  to  run  together  into  piles,
or  rouleaux,  which  arrange  themselves  in  a  small  meshed  network,  as  in
the  adjoining  figure  (a),  (Fig.  35).     Mr.  Wharton  Jones  was  the  first

•  Dr.  Hughes  Bennett's  rpsearches  on  Leueocythsmia  liave  shown  that  even  the
extremest  abundance  of  white  corpiiscles  in  the  blood  has  no  tendency  either  tj  produce
or  to  aggrarate  inflammations.
STATE    OF    THE   BLOOD.
235


to  point  out  that  if  a  drop  of  blood  of  a  patient  suffering  from  acute
rheumatism,  or  inflammation,  be  similarly  examined,  the  piles  of
corpuscles  are  formed  more  rapidly  and  run  more  closely  into  masses,
which  have  large  spaces  between  them  (b).  By  this  arrangement,  the
thin  clot  outspread  on  the  glass  has  the  peculiar  mottled  pink  and
white  appearance,  which  Mr.  Hunter  observed  as  one  of  the  characters
of  inflammatory  blood.  The  same  condition  is  observed  in  the  blood
of  pregnant  women,  and  appears  natural  in  that  of  horses  ;  and  in  all
these  cases  it  may  be  regarded  as  the  chief  cause  of  the  formation  of
the  '  bufiy  coat,'  inasmuch  as  the  clustered  blood-cells,  sinking  rapidly,
generally  subside  to  some  distance  below  the  surface  of  the  liquid  part
of  the  blood,  before  the  ooagalation  of  the  fibrine  is  begun.     This


B


Fig.  33.
aggregation  of  the  corpuscles  does  not  appear  to  be  due,  as  was  at  one
time  supposed,  to  an  increased  viscidity  of  the  liquor  sanguinis  owing
to  an  excess  of  fibrine,  for  Lister's  observations  have  shown  that  they
aggregate  quite  as  closely  after  the  removal  of  the  fibrine,  as  they  did
before.
