16 APPLIED IMMUNOLOGY 



In 1898, Belfanti and Carbone discovered that the 

 serum of horses immunized with the blood of rabbits 

 was very toxic for these animals. The analogy be- 

 tween these cytotoxins or cytolysins and the specific 

 antibodies formed after bacterial inoculations was im- 

 mediately realized. Experiments by Bordet, Ehrlich 

 and iMorgenroth demonstrated the presence of haemol- 

 ysins in the serum of animals inoculated with red 

 blood-cells, and the interesting and important phe- 

 nomenon of haemolysis or solution of erythrocytes was 

 demonstrated. 



Almost all tissue cells were employed in research 

 work for the production of their specific antibodies, 

 and to these various heterogeneous elements the name 

 " antigens " was applied. Thus, leucotoxins, spermo- 

 toxins, trichotoxins, syncytiolysins, hepatolysins, ne- 

 phrolysins and neurotoxins were produced and their 

 influence as causative factors in the pathology of cer- 

 tain diseases, as hepatitis, nephritis, etc., became a 

 much mooted subject in scientific research. In 1900, 

 Uhlenhuth appreciated the formation of specific cyto- 

 toxins for carcinoma and sarcoma in patients, and em- 

 ployed such sera therapeutically. 



The year 1902 is memorable in serology as mark- 

 ing the discovery of the " complement-fixation reac- 

 tion " by Bordet and Gengou. They demonstrated 

 that no haemolysis can occur if the thermolabile ele- 



