haemolysis  is  effective  in  much  weaker  concentration  than  is  quinine 
bihydrochloridCj  the  transition  point  being  reached  with  O'Oiiq  per 
cent,  of  hydrochloric  acid,  while  the  corresponding  weight  of  red  blood 
cells  haemolysed  was  one  hundred  and  eighty-two  times  that  of  the 
hydrochloric  acid  present.  The  action  of  hydrochloric  acid  was  not 
confined  to  the  liberation  of  haemoglobin  from  the  red  blood  cells. 
The  liberated  haemoglobin  quickly  underwent  a  further  change,  a 
soluble  substance  of  brown  colour,  much  more  stable  than  haemo¬ 
globin,  but  giving  no  absorption  bands  on  spectroscopic  examination, 
making  its  appearance. 
4.  Action  of  sodium  hydrate  on  red  flood  cells. 
The  action  of  caustic  alkali  on  red  blood  cells  differs  from  that  of 
the  preceding  haemolytic  agents,  inasmuch  as  with  it  the  transition 
point  at  which  complete  haemolysis  ceases  is  not  sharply  defined,  as 
will  be  seen  on  reference  to  Table  7,  which,  like  Table  6,  is  a  continua¬ 
tion  of  the  series  of  experiments  given  in  Table  2,  but  with  sodium 
Table  7.  Haemolysis  of  red  blood  cells  by  sodium  hydrate  dissolved  in  O'g  per  cent. 
NaCl  solution.  Duration  of  experiment  three  hours.  Temperature  37'  C. 
C'oMPosiTioN  OF  Mixture  of  Rkd  Hlood  Cells  .\nd  Sodium  Hydrate  Solution. 
No.  of 
Experi¬ 
ment 
Sodium  hydrate  o*o2i  9^ 
Weight  of  wet  red  cells  i  13 
Weight  of  sodium  hydrate  i 
0*0 1 8  % 
o-oi6  % 
t 
o-Qt5% 
166 
0-014 
173 
1 
Complete 
Almost 
complete 
Marked 
Marked 
Marked 
z 
Complete 
Almost 
complete 
Marked 
Marked 
Marked 
- 
Complete 
Complete 
Complete 
Complete 
Marked 
\ 
Complete 
Complete 
Complete 
Complete 
Marked 
5 
Complete 
Complete 
Complete 
Complete 
h'larked 
hydrate  substituted  for  quinine  bihydrochloride.  In  these  experiments 
haemolysis  was  complete  as  far  as  a  concentration  of  about  0'0i5  per 
cent,  (chemically  equivalent  to  0-145  per  cent,  of  quinine  bihydro- 
chloride).  At  this  concentration  the  weight  of  red  blood  cells 
haemolysed  was  one  hundred  and  sixty-six  times  the  weight  of  sodium 
hydrate  present.  Thus,  while  the  concentration  of  sodium  hydrate  in 
Table  7  is  only  one-tenth  of  that  of  quinine  bihydrochloride  in 
