148 Influence of Low Temperatures upon Ensymes [March, 



tubes were then prepared, each containing i c.c. of the enzyme sol. 

 and 5 c.c. of the Substrate. The tubes were incubated at 0° C. for 

 periods differing between o min. and 96 hr., then were held at 

 40° C, and the time required at the latter temp. for the production 

 of a coagulum was noted, with the f ollowing results : 



In the last experiment of this serles — held at 0° C. for 96 hr. — 

 the flocculent precipitate was so finely divided that the period of 

 time required for its Separation at 40° C. was determined with 

 difficulty. 



Another series of experiments was carried out as described 

 above, with the single exception that the temp. of mixing the rennin 

 and the milk, and of the preliminary holding, was 15° C. In these 

 experiments the transformation of the casein into paracasein pro- 

 ceeded more rapidly than at 0° C, and consequently less time was 

 required for the Separation of a visible precipitate. For instance^ 

 after holding at 15° C. for periods of o, 10 and 30 min., the co- 

 agula were formed at 40° C. after 6 min., 2^ min., and 55 sec, 

 respectively ; while after 45 min. at 15° C. coagulation had already 

 occurred. 



Müller concludes that rennin exerts its characteristic action, 

 to a certain degree, at 0° C. 



4. Summary. The power to survive prolonged exposure to 



