ANTI-ENZYME IMMUNITY 215 



gift in den Saften des Korpers erzeugt sei, welches das Ferment 

 unwirksam und daher wohl audi sonst unschadlich fiir das Thier 

 macht." 



The six to seven minutes' delay in the appearance of an otherwise 

 instantaneous in vivo reaction fatal to the rabbit was regarded by 

 Hildebrandt as sufficient evidence in support of the existence of anti- 

 emulsin. 



a. Inhibition of the Amylase Activity of Emulsin Preparation by 

 Anti-Emulsin Serum. To prove further that he was dealing actually 

 with immune inhibiton of emulsin activity in vivo, Hildebrandt pro- 

 ceeded to determine the anti-amylase activity of the immune rabbit 

 serum prepared against emulsin. The emulsin preparation hydrolyzed 

 not only the glucosides— amygdalin, salicin, phlorizin, arbutin and 

 coniferin— but also starch. In the presence of normal rabbit blood and 

 emulsin the hydrolysis of starch produced 86.5 per cent reducing 

 sugars within a period of twenty hours; in the presence of immune 

 rabbit blood under similar conditions 39.5 per cent reducing sugars 

 were produced. In separate experiments immune blood alone produced 

 38.5 per cent and emulsin alone 35 per cent reducing sugars. After 

 making the necessary corrections for blanks he calculated that 34.5 

 per cent (47 per cent if compared with the normal blood) less reducing 

 sugars had been produced in the presence of immune rabbit blood. 

 Since the glucoside hydrolyzing activity of emulsin is due to y8-glu- 

 cosidase and this enzyme can now be prepared in relatively pure form, 

 it might be of interest to undertake the production of antibody against 

 )8-glucosidase. 



The production of immunity against the "emulsin" enzyme complex 

 was also reported by Ohta (1913). Repeating the experiments of 

 Hildebrandt he produced immunity in rabbits, the sera of which in- 

 hibited the hydrolysis of amygdalin by the emulsin preparation. 



The hydrolysis of amygdalin was determined in a system containing 

 10 ml. of 2 per cent amygdalin solution, 0.1 ml. of 1 per cent emulsin 

 extract, 1 to 4 ml. of immune or normal rabbit serum and 9.0 ml. of 

 normal saline. The reaction mixture was then incubated at 37°C. 

 for 24 hours under sterile conditions. The rate of the hydrolysis of 

 amygdalin was determined by estimating the quality of glucose pro- 

 duced after removing the proteins with colloidal iron. The results are 

 summarized in Table VIII. The results show that anti-emulsin sera 



