A  further  relation  exists  to  which  reference  may  be  made.  So 
long  as  the  haemolysis  of  red  cells  proceeds  at  a  monomolecular  rate 
the  amount  of  red  cells  haemolysed  during  any  short  period  of  time 
is  closely  proportional  to  the  concentration  of  the  red  cells  in  the 
emulsion  at  the  beginning  of  the  period.  This  is  seen  to  be  the  case 
for  Table  15,  in  which  the  weight  of  red  cells  haemolysed  each  half 
hour  is  found  to  be,  for  the  calculated  amounts,  almost  exactly  0'236 
of  the  concentration  at  the  beginning  of  each  period  [thus 
9I'2  6g'5  =  2i7  =  gr2  xo-238,  and  so  on]. 
;.  A  ction  o  f  quinine  on  healthy  red  cells  in  the  living  body. 
The  experiments  recorded  in  Table  4  show  that  quinine  bihydro¬ 
chloride  scarcely  has  an)'  action  upon  red  blood  cells  until  its  concen 
Iration  reaches  0'5  per  cent.  If  the  percentage  of  quinine  salt  falls 
below  this  amount  extremely  little  change  takes  place  on  keeping- 
three  hours  at  37°  C.  Assuming  the  amount  of  blood  in  the  human 
body  to  be  5,000  c.cm.,  the  amount  of  quinine  bihydrochloride  required 
to  produce  a  concentration  of  0'5  per  cent,  would  be  25  grammes 
(38;  grains),  that  is  0-3  g.  per  kilo  of  body  weight,  if  the  quinine 
were  introduced  intravenously.  .Since  a  dose  of  this  amount,  which 
would  be  rapidly  fatal,  is  far  above  the  maximum  amount  taken 
Table  22.  Quinine  in  relation  to  bl.nckwater  fever. 
Case 
Amount  of  quinine  taken 
Relation  to  appearance  of  blackwater 
.4 
8  grs.  at  mid-day,  8  grs.  at  3  p.m. 
Passed  blackwater  at  6  p.m. 
B 
Two  Jo-gr.  doses  in  afternoon  and  evening. 
Passed  blaclavater  at  i  a.m. 
C 
1  (i)  10  grs.  a  day  for  two  davs. 
Passed  blackwater  on  the  third  day. 
D 
1  W  (A  year  later)  10  grs.  at  6  a.m, 
Passed  blackwater  at  7  or  8  a.m. 
1  (i)  10  grs. 
Passed  blackwater  soon  afterwards. 
E 
1  (2)  5  grs.  hypodermically. 
Passed  blackwater  one  and  a  half  hours  later. 
to  grs,  in  evening. 
Passed  blackwater  next  morning. 
F 
6  grs.  before  and  6  grs.  after  dinner. 
Passed  blackwater  in  night. 
G 
Three  5-gr.  doses  of  quinine. 
After  the  first  dose  passed  brown  urine. 
H 
5  grs.  of  quinine  a  day  for  two  dave. 
Took  no  more  medicine. 
Blackwater  on  the  fifth  day. 
i 
10  grs.  for  two  evenings. 
Blackwater  second  night. 
j 
6  grs.  hypodermically  at  10  a.m. 
Urine  porter  coloured  at  mid-day. 
K 
10  grs. 
Blackwater  next  day. 
L 
35  grs.  in  5-gr.  doses  in  two  days. 
Blackwater  on  third  day. 
M 
9  grs.  on  two  successive  mornings. 
Urine  dark  on  second  morning,  porter 
coloured  same  evening. 
