ANTI-ENZYME IMMUNITY 



307 



Thaysen did not believe that the neutralizing power of the immune 

 serum was due to a specific antigen-antibody reaction. He postulated 

 two possibilities: (a) a pH difference between immune and normal 

 sera; (b) an increase in the concentration of "adsorbing bodies" or 

 "some substance" in the serum of immunized rabbits, which appar- 

 ently does not exist in the sera of normal rabbits. Since he did not offer 

 any experimental data regarding his "adsorbing bodies," as being 

 different from antibodies, this idea must be dismissed as speculation. 

 An analysis of Thaysen's data will also show that his other postulate 

 lacks any experimental basis; 0.2 ml. of immune serum (ca. pH 7.8) 

 is incapable of alkalinizing and thereby inactivating 1 ml. of rennin 

 solution (the optimal activity lies in the range of pH 6.0-6.4) in 10 

 ml. of milk (pH 6.58) which possesses very strong buffering capacity 

 (Moser, 1927). If there ever exists any inactivation following the 

 action of alkaline immune serum on rennin, this effect will be reversed 

 on being exposed to the reactivating pH of the milk. This is illustrated 

 by the following facts. Kleiner and Tauber (1932) made a calcium 

 carbonate extract of the mucosa of the fourth stomach; the pH of the 

 extract was 7.4. One ml. of this extract clotted 30 ml. of milk in 10 

 minutes at 40°C. without the addition of acid to the extract. The rennet 

 activity of this extract was lost entirely only after two-day incubation 

 at 37°C. As soon as the pH was adjusted to 5.3, the immediate milk 

 clotting activity was 1 : 333; activity after one day's incubation at 37°C. 

 was 1 : 420. The reversible inactivation of rennet compares very 

 favorably with those of other enzymes (Northrop, 1939). 



H. ENZYMATIC AND PHARMACOLOGICAL ACTIVITIES OF 

 HEMOLYTIC SUBSTANCES 



1. Hemolytic Lysolecithin Derived by the Action of 

 Snake Venom Lecithinase 



Stephens and Myers (1898) reported that on mixing cobra venom 

 with guinea pig blood in vitro they observed hemolysis and the delay or 

 complete absence of clotting of blood. Investigating this observation 

 further, they found that the hemolytic action of 0.1 mg. of venom on 

 guinea pig blood was completely arrested by 0.1 ml. of immune serum. 

 The reaction was specific, as other horse immune sera, such as diph- 



