^7 
is  well  mai'ked,  and  occurs  when  a  concentration  of  quinine,  bihydro 
chloride  amounting  to  O' 155  per  cent,  is  reached.  It  will  be  noticed 
that  in  two  members  of  the  series,  haemolysis,  at  the  transition  point, 
was  nearly  but  not  quite  complete  at  the  end  of  three  hours  at  37°  C., 
the  rate  at  which  the  reaction  proceeded  being  in  these  two  cases 
slightly  slower  than  in  the  remaining  members  of  the  same  group. 
In  the  succeeding  concentration  [o’ 134  percent.]  of  quinine  salt  haemo¬ 
lysis  is  partial  or  slight,  and  in  the  remaining  concentration  (o'liq  per 
cent.)  but  little  haemolysis  occurs.  In  these  experiments  it  is  seen 
that  a  given  weight  of  quinine  bihydrochloride,  does  not  haemolyse  a 
fixed  weight  of  red  blood  cells  during  the  period  of  experiment  (three 
hours),  but  that  the  maximum  weight  of  red  blood  cells,  which  can 
be  haemolysed,  depends  upon  the  concentration  of  the  quinine  salt, 
not  upon  its  absolute  amount. 
A  third  series  of  experiments  was  now  carried  out  with  still 
higher  concentrations  of  quinine  salt  (Table  3).  Here,  as  before,  the 
transition  point  was  well  marked.  It  was  obtained  when  a  concen 
tration  of  quinine  salt  amounting  to  0‘635  per  cent.,  i.e.  about  fourteen 
times  that  obtaining  in  the  first  series  |o'045  per  cent.]  and  nearly 
Table  3.  Haemolysis  of  red  blood  cells  b\  quinine  bihydrochloride,  in  nearly  fourteen 
times  the  concentration  employed  in  'Table  i.  Duration  of 
experiment  three  hours.  'I'cmperaiure  37:  C'. 
No.  of 
Experi¬ 
ment 
Composition  of 
Mixture  oh 
Red  Bi.ooi 
Cells  and 
Quinine  Solution. 
Quinine  hydrochloride  0*844. ‘Ig 
Weight  of  wet  red  blood  cells  22 
Weight  of  quinine  salt  i 
°'724'.’o 
I 
% 
.’^4 
1 
0-527 
47 
I 
°'44» 
.^7 
r 
I 
Complete 
Complete 
Complete 
Partial 
Slight 
2 
C’.ompletc 
Complete 
Marked 
Partial 
Slight 
.I 
Complete 
Complete 
Complete 
.Marked 
Slight 
4 
Complete 
Complete 
Complete 
Partial 
Slight 
5 
Complete 
Complete 
Complete 
Partial 
Slight 
two  and  a  half  times  that  present  m  the  second  series  [o' 155  per  centj , 
was  reached.  The  weight  of  the  red  blood  cells  haemolysed  was 
36' 5  times  that  of  the  quinine  salt  present.  As  in  the  second  series, 
so  again  here,  the  increase  in  the  amount  of  red  blood  cells  haemolysed 
is  not  in  the  same  proportion  as  is  that  of  quinine  salt  present,  but 
is  much  smaller  than  the  latter. 
B 
