37 
in  which  haemolysis  proceeded  relatively  slowly,  and  low  in 
Experiments  i  and  3,  in  which  haemolysis  was  relatively  rapid,  yet 
these  variations  are  inconsiderable,  the  values  of  ix  lying  within  a 
narrow  range,  the  highest  mean  value  being  18,000  and  the  lowest 
1 1.600,  the  mean  of  all  being  1 5,000.  From  the  latter  value  of  fx  the 
lowering  of  the  temperature  required  to  diminish  the  rate  of  reaction 
to  one-half  may  be  calculated;  at  37°  C.  it  amounts  to  9°  C.  With 
the  aid  of  this  mean  value  of  15,000  the  percentages  m  Experiments 
I  to  4,  Table  17,  are  re-calculated,  the  values  of  K  thus  obtained  not 
differing  greatly  from  those  determined  by  experiment.  The 
difficulties  in  the  way  of  carrying  out  these  experiments,  it  may  be 
observed,  are  by  no  means  inconsiderable. 
Additional  confirmation  of  the  conclusion  already  reached  (p.  31), 
that  haemolysis  produced  by  the  action  of  quinine  in  the  alkaloidal 
form  resembles  a  chemical  process,  not  a  physical  one,  is  thus  afforded 
by  the  circumstance  that  approximately  identical  values  of  fx  are 
obtainable  in  the  experiments  at  varying  temperatures  recorded  in 
Table  18. 
The  fact  that,  in  the  heterogeneous  system  formed  by  red  blood 
cells  suspended  in  a  hydrosol  of  alkaloidal  quinine,  haemolysis 
progresses,  except  at  the  beginning  and  end  of  the  process,  at  a  mono- 
molecular  rate,  indicates  that  quinine  behaves  like  a  catalytic  agent, 
its  action  being  similar  to  a  ferment  action  comparable,  for  example 
to  that  of  pepsin.  Quinine  bihydrochloride,  hydrochloric  acid  and 
sodium  hydrate  presumably  also  act  like  catalytic  agents.  ae 
resemblance  of  these  haemolytic  agents  to  pepsin  is  all  the  greater 
when  it  is  borne  in  mind  that  the  amount  of  red  cells  completely 
haemolysed  in  three  hours  at  37°  C.  is  proportional  to  the  square  root 
of  the  concentrations  employed,  for  precisely  the  same  relationship 
holds,  within  certain  limits,  for  pepsin.^  The  value  of  ix  for  the 
digestion  of  gelatine  by  pepsin  was  found  by  Sjbqvist  to  be  10,750. 
and  for  the  digestion  of  egg-albumin  by  pepsin  to  be  i  5,570-  ese 
values  are  not  far  removed  from  those  obtained  for  the  haemolysis  of 
red  cells  by  quinine. 
It  is  to  be  anticipated  that,  as  quinine  m  the  free  state,  m 
producing  haemolysis  of  red  blood  cells,  resembles  a  catalytic  agent. 
K  Sjoqvist,  Scandin.  Archiv.  f.  Physiologie,  5  (1805). 
