54 



IMMUNE SERA 



of species B, acquires an increased solvent action 

 for erythrocytes of species B, and only for this 

 species. 1 It is therefore a specific action. We call 

 this hcemolysis, and the substances which effect 

 the solution of the red cells, hcemolysins or hczmo- 

 toxins. 



At about the same time, and independently of 

 Bordet, similar experiments with similar results 

 were published by Landsteiner 2 and v. Dungern. 3 

 As a result of this work, the acquired toxicity of 

 horse serum, found by Belfanti and Carbone when 

 they treated horses with red cells of rabbits, was 

 explained. The serum of the horses so treated had 

 become h&molytic for rabbit blood, and therefore 

 caused a solution or destruction of the red cells 

 in the living body just as it did in a test-tube. 



Nature of Hcemolytic Sera. In a subsequent 

 study Bordet 4 was able to show that the sol- 

 vent power of the specific haemolysins depended 

 on the combined action of two constituents of the 

 specific serum. When the fresh haemolytic serum 

 was heated for half an hour to 55 C., it lost its 

 power. If to this inactive serum a very small 

 amount of the serum of a normal guinea pig was 

 added (a serum which of course was not haemolytic 

 for rabbit red cells), the full haemolytic power was 



1 We shall point out a few exceptions later on. 



2 Landsteiner, Centralblatt Bacteriol., Vol. xxv, 1899. 



3 Von Dungern, Munch, med. Wochenschrift, 1898. 



4 Bordet, Annal. Inst. Pasteur, Vol. xii, 1898. 



