CHAPTER VIII 

 THE COMPOUND H^MOLYSINS 



SINCE the earliest times the injection of the blood of ani- 

 mals into the veins of the human sick has been practised 

 for therapeutic purposes. It was always known that these 

 experiments with " transfusion " of blood were dan- 

 gerous, and it was later determined that the serum from 

 animals exerts a " globulicidal " action on the erythrocytes 

 of human origin. Only the blood of the same species 

 (isoserum) is innocuous. 1 



The normal serum of an animal contains a substance 

 which haemolyses the erythrocytes of animals of other 

 species, and this substance was called alexin (protecting 

 substance) by Buchner, who determined also that the alexin 

 is rapidly decomposed at a temperature of 55 C. or more. 



The haemolytic properties of the blood-serum of an 

 animal are increased to a high degree if the animal be im- 

 munised by the injection of erythrocytes of another species. 

 The haemolytic action is in this case specific against ery- 

 throcytes of the variety employed in the injections. This 

 observation was made by Bordet, 2 who found also that the 

 haemolytic properties vanish after heating for thirty min- 



1 Landois: "Die Transfusion des Blutes," Leipzig, 1875, cited from Hans 

 Sachs: "Die Hamolysine" in Lubarsch-Ostertag's Ergebnisse d. pathol. 

 Anatomic, Vol. 7, 1902. This memoir contains a review of the literature on 

 this subject up to that time, and of the results attained. 



2 Bordet: Ann. de. I hist. Pasteur, 12 (1898). 



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