'  f>5 
disturbance,  and  a  toxic  agent.  Another  point  of  resemblance  lies 
in  the  circumstance  that  in  both  cases  blood  destruction  (changes  in 
the  red  cells  may  be  obtrusive  after  the  administration  of  potassium 
chlorate)  has  been  occurring  previous  to  the  appearance  of  haemo- 
globinuria  resulting  in  more  or  less  severe  anaemia.  In  both  cases 
an  increased  blood  destruction  occurs  as  soon  as  haemoglobinuria 
makes  its  appearance.  It  is,  however,  uncertain  whether  the  blood 
destruction  in  these  cases  is  attended  with  discharge  of  haemoglobin 
into  the  blood  plasma,  destruction  or  removal  of  haemoglobin  (cp. 
Exp.  10,  Table  35)  occurring  so  rapidly  that  the  degree  of  haemo- 
globinaemia  is  insufficient  to  lead  to  haemoglobinuria,  or  whether  the 
destruction  takes  place  without  any  such  liberation  of  haemoglobin 
into  the  blood  plasma.  In  the  first  case  the  difference  between  the 
first  process  and  the  haemoglobinaemia  of  blackwater  fever  would  be 
only  one  of  degree  ;  in  the  latter  case  the  difference  between  the  two 
processes  v^ould  be  a  qualitative  one.  In  the  former  case  quinine, 
potassium  chlorate,  etc.,  would  act  merely  by  accelerating  the  rate  of 
discharge  of  haemoglobin  into  the  blood  plasma ;  in  the  latter  case 
by  inducing  a  new  process.  It  is  of  interest  to  refer  in  this  connection 
to  the  circumstance  that  malaria  alone  may  cause  blackwater  fever. 
Twenty-four  such  cases  are  described  by  A.  Plehn.* 
SUMMARY 
1.  In  the  urine  in  blackwater  fever  red  cells  may  be  found  during 
haemoglobinuna,  usually  in  very  small  numbers. 
2.  In  blackwater  fever  the  haemoglobinuria  which  occurs  is  the 
result  of  an  accompanying  haemoglobinaemia. 
Sufficient  data  are  not  available  to  determine  the  situation  in 
which  laking  of  red  cells  leading  to  haemoglobinaemia  occurs  in 
blackwater  fever. 
ADDITIONAL  NOTE 
Redwater  in  firoflasmosis.  Haemoglobinuria  m  the  dog,  due  to 
piroplasma  canis,  is  similar  in  its  mechanism  of  production  to  that  of 
blackwater  m  the 'human  subject,  that  is  to  say,  the  haemoglobinuria 
is  attended  with  and  dependent  upon  haemoglobinaemia.  A  series  of 
data  obtained  in  experimental  piroplasmosis  of  dogs  will  shortly  be 
ready  for  publication. 
•S.  Pathogenese  des  .Schwarzwasserfiebers.-,  Virch.  ArchTTgoj.^rTyV, 
