I.?  I 
been  observed  in  blackwater  fever,  in  particular  fragmentation  of  the 
red  cells,  were  present,  and  in  the  kidneys  e]>ittielial  degeneration  was 
fre(|ucntly  obser\ed.  I 'nforiiina1<'l)',  in  eoiisecjiuMice  of  the  com¬ 
plexity  of  these  experiments,  in  which,  to  use  a  mathematic.il 
expression,  several  variables  occur  together,  it  is  difficult  to  lie  (juite 
sure  of  the  relation  of  the  pathological  conditions  present  to  the 
hacmoglobinuria  and  anuria,  nr  to  be  certain  of  tlie  identity  of  the 
anuria  so  produced  with  that  occurring  in  blackwater  fever,  in  spite 
of  the  similarity  of  the  asjiect  of  the  kidiu-ys  in  the  two  cases.  To 
ascertain  the  mechanism  of  production  of  the  hacmoglobinuria  and 
anuria  in  sucli  investigations  it  is  essential  to  cx|)criment  as  far  as 
jinssible  with  a  single  pathological  condition  at  a  time.  The 
experiments  in  (pieslion,  however,  if  not  as  illuminating  as  could  be 
desired,  are  very  suggestive  and  of  considerable  interest. 
I'rom  the  foregoing  dcscri]ition  of  the  condition  of  the  kidneys 
in  suirprcssion  of  urine  in  blackwater  fever,  the  mechanism  of  this 
process  becomes  at  once  (juitc  clear.  The  suppression  is  not  a 
functional  state,  but  is  a  purely  mechanical  process  due  to  blocking 
of  the  collecting  tubules  by  plugs  composed  of  densely  packed  dark 
reddish  granules,  identical  with  the  casts  observed  in  the  urine  during 
supiiression  (Cases  ya  and  i  i,  Fig.  32),  and  passing  1))’  every  transition 
into  the  casts  ordinarily  found  during  blackwater  not  attended  with 
suppression,  the  flifference  between  the  two  lying  in  the  large  size 
of  the  granules  and  greater  firmness  of  the  casts  in  the  former  as 
compared  with  the  latter,  and  also  in  the  firm  adhesion  to  the 
epithelial  lining  of  the  tubules  in  the  former  case. 
The  effect  of  the  plugging  is  .seen  in  the  distension  of  the 
uriniferous  tubules  and  A'lalpighian  cajisules  leading  to  the  consider¬ 
able  general  enlargement  of  the  kidney  observed  at  death  (Figs,  bi 
and  62). 
DESCRIPTION  OF  ILLUSTRATIONS 
I'rc..  5;j.  Section  of  cortex  of  kidney  during  .suppression  of  uiiiic,  eiglu 
<lays  after  haenioglobinuria  liad  ceased.  Illackwater  Fever,  Case  7a. 
.‘V  convoluted  tubule  is  shown  across  obli(|uely.  'I'be  lumen  of  the 
tubule,  which  is  dilated,  contains  numerous  darkly  stained  masses 
measiuing  ’n  to  25/4  across,  con-isting  of  gr.uiulcs,  2/4  to  5^4  in 
diameter  exibibiting  varying  degrees  of  coalescence.  The  renal 
eiiithelium  is  not  markedly  changed.  No  free  epithelial  cells  are 
seen  in  the  lumen  of  the  tubule.  Hardened  in  alcohol.  Stained 
with  iron  alum  haematoxylin.  x  S50. 
