HEMOLYSINS. 131 



Hemolysins. 



An animal that is injected with the red blood cells of a different species, 

 develops in its serum antibodies which are biologically analogous to bac- 

 teriolysins and differ from them only in that they cause disintegration of 

 erythrocytes instead of bacteria. These antibodies are therefore called 

 hemolysins, or to be more precise immune-hemolysins, since they arise 

 through a process of immunization. The breaking up of the red blood 

 corpuscle, hemolysis, is recognized by the naked eye. The hemoglobin 

 passes from the erythrocytes into the surrounding fluid (serum or physiolog- 

 ical salt solution) and colors it red. The previously opaque blood, lakes 

 and becomes transparent. Immune-hemolysins like bacteriolysins belong 

 to the class of amboceptors. They are relatively thermolabile in that they 

 withstand a temperature of from 56 to 58 C. without being injured, and 

 they require complement for the development of their hemolytic action. 

 Furthermore, immune-hemolysins like all amboceptors, are specific, i.e., 

 the serum of a rabbit immunized against horse's blood can dissolve only the 

 blood of a horse and not that of a hen or cow. On the other hand, group 

 reactions occur here also; for instance the immune-hemolysin produced in a 

 rabbit against horse's blood is likewise active against donkey's blood. 



Just as various antitoxins, agglutinins, precipitins and bac- 



Normal teriolysins can be found in normal serum, so also normal 



Hemolysin. hemolysins of amboceptor structure can be discovered in the 



blood of many species of animals or individual animals. 

 While normal hemolysins come into play in only a few reactions, as in 

 several modifications of the Wassermann test, the significance of immune- 

 hemolysins is extraordinarily great. These antibodies, discovered by 

 Bordet, and independently by von Dungern and Landsteiner, were carefully 

 studied by Ehrlich and Morgenroth and many others. Such researches 

 have, first of all, greatly advanced the subject of immunity in its theoretical 

 aspects, in that they have created the possibility for the discovery in minute 

 detail the finer relationship which has explained some of the phenomena 

 occurring in bacteriolysis. Furthermore, the studies of hemolysins led to the 

 discovery of the complement fixation method, a procedure of exceptional 

 practical value. 



As far as the technique for obtaining immune-hemolysins is 



Production concerned, the rules which hold for every process of immu- 



of Hemolytic nization are naturally to be followed here also. It is not 



Sera. possible, however, to immunize every kind of animal against 



every type of red blood corpuscles. Rabbits, goats, horses 

 and chickens are the ones which are best adapted to supply hemolytic sera. 

 An animal produces a better hemolysin the remoter its relationship to the 

 animal from which the erythrocytes for injection are taken. The blood to 



