74 
When  the  blood  of  indi\'iduals,  not  in  normal  health,  but  suffering 
from  malaria  or  other  affections  met  with  m  the  tropics,  was  examined 
it  was  found  that  the  variations  in  the  amount  of  haemoglobin 
dissolved  in  the  blood  plasma  lay  within  much  the  same  limits  as  in 
health  (Table  32).  Thus  in  fourteen  cases  of  malaria  the  percentage 
of  dissolved  haemoglobin  in  the  blood  plasma  ranged  in  twelve  cases 
between  0'02  per  cent,  and  o-20  per  cent.,  but  reached  in  two  cases 
the  somewhat  high  degree  of  0-31  per  cent,  (in  neither  of  the  two 
latter  did  blackwater  fever  make  its  appearance) ;  in  the  remaining 
seven  cases  (dysentery,  diarrhoea,  etc.)  the  range  was  between  0^04 
per  cent,  and  O' 16  per  cent.  It  may  here  be  noted  that  in  perfectly 
healthy  rabbits  and  oxen  we  have  failed  to  find  dissolved  haemoglobin 
in  the  oxalatecl  blood  plasma.  Examined  in  the  above  described 
manner  it  was  found  that  the  blood  plasma  in  blackwater  fever  gave 
l^ercentages  of  dissoh'ed  haemoglobin  ranging  from  less  than  o'o6  per 
cent,  to  095  per  cent,  (fable  33).  The  number  of  cases  examined 
was  seventeen,  and  the  number  of  estimations  made  amounted  to 
forty.  The  observations  fall  into  three  classes:  those  made  before, 
after  and  during  the  passage  of  blackwater,  In  the  first  class,  which 
includes  only  three  observations  (i,  2,  5),  the  percentage  of  dissolved 
haemoglobin  was  0-13  per  cent,  or  less.  In  the  second  class,  which 
includes  eighteen  observations  (4,  8,  9,  10,  ii,  12,  13,  14,  15,  17,20,26, 
27,  28,  29,  31,  35,  40),  usually  made  shortly  after  the  close  of  the  attack, 
the  percentage  of  dissolved  haemoglobin  was  from  0'20  per  cent,  to 
0  06  per  cent.  In  the  third  class,  consisting  of  nineteen  observations 
given  in  Table  33  m  thick  type,  the  percentage  of  dissolved 
haemoglobin  was  in  twelve  (6,  7,  18,  21,  23,  30,  33,  34,  36,  37,  38,  39) 
cases  raised  lying  between  o'ps  per  cent,  and  0-30  per  cent  •  in  the 
remaining  seven  (3,  16,  19,  22,  24,  25,  32)  observations  it  lay  within 
the  limits  met  with  in  health,  namely.  0-25  per  cent,  to  o'og  per  cent 
With  regard  to  the  latter,  it  must  be  remarked  that  although  in  these 
observations  the  first  specimen  of  urine  voided  after  the  examination 
of  the  blood  plasma  contained  haemoglobin,  as  will  be  seen  by 
reference  to  the  clinical  histories  on  pp.  176  to  246  ;  nevertheless  it 
does  not  follow  that  the  urine  which  was  being  excreted  at  the  time 
of  examination  of  the  blood  plasma  then  contained  haemoglobin. 
It  IS  possible,  if  not  probable,  that  in  some  cases  the  haemoglobin 
had  already  disappeared,  though,  owing  to  the  relatively  long  intervals 
