tLEMOLYSINS, CYTOTOXINS, AND 

 PRECIPITINS. 



I. H^MOLYSINS. 



IN 1898 Belfanti and Carbone showed that if 

 horses were injected with red blood-cells of rab- 

 bits, the serum thereafter obtained from the horses 

 would have acquired an appreciable toxicity for 

 rabbits. Shortly after this Bordet published a 

 very interesting series of experiments. He showed 

 that the serum of guinea-pigs after these had been 

 injected several times with 3 to 5 c.c. of defibrin- 

 ated rabbits' blood acquires the property to dis- 

 solve rapidly and intensely, in a test-tube, the red 

 blood-cells of a rabbit; whereas the serum of a 

 normal guinea-pig is incapable of doing this, or 

 does it in only a slight degree. Bordet could 

 further show that this action is a specific one, i.e., 

 the serum of animals treated with rabbit blood 

 acquires this dissolving property only for the red 

 cells of rabbits, not for those of any other species 



