25 
alkaloidal  form,  and  hydrochloric  acid.  On  this  account  the  produc¬ 
tion  of  a  relatively  greater  degree  of  haemolysis  is  to  be  expected.” 
Taking  all  these  facts  into  consideration,  the  results  in  Table  12 
certainly  suggest  that  in  all  cases  the  same  process  is  at  work,  in 
other  words,  that  whether  haemolysis  is  caused  by  quinine  salt,  by 
quinine  in  the  alkaloidal  state,  by  hydrochloric  acid,  or  by  sodium 
hydrate,  an  identical  reaction  occurs.  This  point  will  be  further 
referred  to  in  the  next  section. 
In  addition  to  their  haemolytic  power  the  four  substances  in 
question  may  also  be  compared  in  respect  of  several  other  features. 
In  the  first  place  the  sharpness  of  the  transition  point  may  be 
considered.  This,  as  has  already  been  mentioned,  is  well  defined  for 
quinine  bihydrochloride,  quinine  in  the  free  state  and  hydrochloric 
acid.  If  the  series  of  tubes,  in  which  the  mixtures  of  haemolytic 
agent  and  red  blood  cells  are  contained,  is  examined  at  the  end  of 
three  hours  at  37°  C.,  it  is  found  that  haemolysis  is  complete  in  all 
tubes  up  to  the  transition  point.  In  the  next  tube  there  is  more  or 
less  incomplete  haemolysis.  In  the  succeeding  tube  the  haemolysis  is 
slight,  and  in  further  tubes  the  supernatant  liquid,  left  after  centri- 
fugalising,  shows  no  indication  of  laking  recognisable  with  the  naked 
eye.  With  sodium  hydrate,  however,  although  the  transition  point 
can  be  recognised,  there  is  no  sudden  cessation  of  haemolysis  in  the 
tubes  lying  beyond  this  point,  but  instead  the  degree  of  haemolysis 
lessens  very  gradually,  most  of  the  red  cells  present  in  the  fifth  or 
sixth  tubes  beyond  that  of  the  transition  point  being  genera  11}' 
haemolysed. 
Table  12.  Comparison  of  the  action  on  human  red  blood  cells  of  quinine  bihydro- 
chloridc,  quinine  in  alkaloidal  state,  hydrochloric  acid  and  sodium  hydrate  in  the  same 
molecular  concentration.  The  amounts  of  red  cells  given  were  the  largest  amounts 
which  could  be  completely  haemolysed  in  three  hours  at  37°  C. 
Table 
Haemolytic 
agent 
Concentration  of 
haemolytic  agent 
Weight  of  wet  red 
cells :  \^'eight  of 
haemolytic  agent 
Wet  red  cells  (in 
grammes)  :  haemo¬ 
lytic  agent 
(gramme-molecule) 
I 
Q.  2  HCl 
0-0450%  =  0-001 1 3  M 
10*4  :  I 
4130  :  I 
9 
Q.  (alkaloid) 
0*0366  %  =  0*00113  M 
4-8  :  1 
1550  :  1 
10 
HCl 
0-0041  %  =  0-001 13  M 
91*1  :  ! 
3220  I 
1 1 
NaOH 
0-0045  %  =  0-00113  M 
I  I  3  :  I 
4520  ;  I 
*  In  0-00113  iVi  concentratiiiu  quinine  bihytlrochloritie  is  hydrolysed  to  the  extent  of 
about  ten  per  cent. 
