2 IMMUNE SERA. 



of animal. For the latter, such a serum is no more 

 strongly solvent than the serum of a normal animal. 

 The same property that Bordet had demonstrated 

 in the serum of guinea-pigs treated with rabbit 

 blood could now be shown for the sera of all ani- 

 mal species treated with blood-cells of a different 

 species. We can formulate this as follows: The 

 serum of animals, species A, after these have been 

 injected either subcutaneously, intraperitoneally, 

 or intravenously with erythrocytes of species B, 

 acquires an increased solvent action for erythro- 

 cytes of species B, and only for this species.* It 

 is therefore a specific action. We call 'this hce- 

 molysis, and the substances which effect the solution 

 of the red cells, h&molysins or hcemotoxins. 



At about the same time, and independently of 

 Bordet, similar experiments with similar results 

 were published by Landsteiner and v. Dungern. 

 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. 



Agglutinating Power of Haemolytic Serum. As a 

 further result of his experiments Bordet showed 

 that in this haemolytic serum still another property 



* We shall point out a few exceptions later on. 



