3 1 6 IMMUNO-CATALYSIS 



on the concentration of antiricin present in the ricin-antiricin neutral 

 mixture, red blood corpuscles exercised the power of dissociating ricin 

 from the neutral mixture and fixing it. Despite the great affinity 

 between ricin and red blood corpuscles on one hand, and lecithinase 

 activity of ricin on the other, the hemolysis does not appear to take 

 place so readily. Pascucci (1905) on the other hand reported that ricin 

 acting on a saline emulsion of lecithin produced a flocculent precip- 

 itate. The filtrate from the precipitate added to red blood cells 

 produced immediate hemolysis. 



Bertarelli (1926) also reported that ricin possesses lipase activity. 

 The lipase activity was determined by titrating with standard alkali 

 solution the acidity developed after ricin had acted on olive oil for 

 two hours at 37°C. Immune rabbit or dog sera prepared against the 

 ricin preparation exercised appreciable inhibition (25 to 30 per cent) 

 on the lipase activity of ricin. He did not observe any inhibitory effect 

 by immune sera on lipase activity of normal serum, or pancreas and 

 liver extracts. 



More definite information was obtained by Neuberg and Rosenberg 

 (1907) and Neuberg and Reicher (1907) regarding the relation of 

 the lecithinase activity of ricin to hemolysis. They compared the lipase 

 and lecithinase activity of ricin with those of snake venoms and also 

 of bee poisons, and found all of them to possess strong lipolytic activity. 

 Investigating the lipolytic and hemolytic properties of the culture 

 filtrates of various bacteria, they found that while the hemolytic filtrates 

 of cholera vibrios, staphylococcus and meningococcus exercised weak 

 lipase activity on olive oil, lecithin and castor oil were strongly hydro- 

 lyzed. Ricin likewise strongly hydrolyzed lecithin and castor oil. The 

 hydrolytic mixture of lecithin was hemolytic. Neuberg, et al. (1907) 

 reported that antiricin immune serum completely neutralized the 

 lecithinase and lipase activity of ricin. 



3. Bacterial Hemolysins 



The mechanism of hemolysis by bacterial filtrates has until recently 

 remained relatively obscure. The reason probably was the absence of 

 sufficient chemical data as to the nature of hemolysins and their 

 various chemical and physical properties. It is known that numerous 

 pathogenic and non-pathogenic micro-organisms elaborate hemolytic 



