HAEMOLYSIS 181 



it has been injected. For example, the serum of a normal 

 rabbit has no haemolytic action upon the red corpuscles 

 of the sheep ; but if a rabbit receive a few injections of 

 defibrinated sheep's blood, its blood-serum acquires 

 haemolytic properties and dissolves the red corpuscles of 

 the sheep. This solution of the blood- corpuscles is termed 

 " haemolysis," and the substances which produce haemo- 

 lysis are " haemolysins." If the active serum be heated to 

 56 C. it is " inactivated " and loses its haemolysing 

 power, but can again be rendered haemolytic or " acti- 

 vated " by the addition of fresh normal serum ; normal 

 serum, however, rapidly loses its activating properties 

 on keeping. It will thus be seen that there is an almost 

 complete analogy between bacteriolysis and haemolysis, 

 the latter being brought about by the interaction of two 

 substances, one specific and stable produced by the injec- 

 tions, the haemolytic " amboceptor " or " immune body," 

 and the other an unstable body present in fresh normal 

 serum, the " complement " or " alexin." 



Haemolysin formed by the injection of corpuscles of 

 another species is termed " heterolysin." If corpuscles 

 of the same species be injected, haemolysin is formed 

 (" isolysin "), but the injection of the animal's own cor- 

 puscles does not give rise to haemolysin, i.e. " autolysin " 

 is not formed. 



Blood- corpuscles are more tangible entities than bac- 

 teria, and are far easier to work with than the latter, and 

 haemolysis has been the subject of a large amount of 

 experimental work by Bordet and Gengou, Ehrlich, Mor- 

 genroth, Gruber, Bulloch, Muir, and others, and the results 

 obtained have shed considerable light upon the complex 

 phenomena of immunity and of the actions of anti- bodies 

 in general. Moreover, the globulicidal material in haemo- 

 lysis seems to be identical with the bactericidal one in 

 bacteriolysis that is to say, it is the complement or 



