I9IS] Joseph Samuel Hepburn I43 



25° C, 44 hr. at 8° C, or 72 hr. at o*^ C. Therefore, even at the 

 latter temp., diastase transformed starch through the stages of 

 soluble starch and erythrodextrin to maitose. 



Invertase, maltase^ zymase. These enzymes are active at the 

 temp. of an ice box, for, according to Buchner (16), yeast press- 

 juice produced alcoholic fermentation of s'ucrose, maitose, glucose, 

 and fructose at that temp. 



Pepsin (gastric Protease). Murisler and Fick (17) ex- 

 tracted finely divided gastric muscosae from various animals with 

 40-fold their weights of water, and permitted these extracts to act at 

 various temp. on small cubes of coagulated albumen in the presence 

 of hydrochloric acid. The extracts of the gastric mucosae from 

 pigs and dogs rarely acted upon coagulated albumen at temp. below 

 10° C. and never acted, even in the slightest degree, at 0° C. On 

 the other hand, pepsin extracts prepared with gastric mucous mem- 

 branes from frogs, pike and trout, regularly digested coagulated 

 albumen at 0° C, and were fully as active at 40° C. as were the ex- 

 tracts obtained with mucosae from pigs and dogs. From these ex- 

 periments, which were qualitative, Murisier and Fick concluded that 

 the gastric protease of cold blooded animals is not completely iden- 

 tical with that of warm blooded animals. 



This opinion was shared by Hoppe-Seyler (18), who studied the 

 action, upon fibrin shreds, of artificial gastric juice prepared with 

 mucous membrane from pike stomachs. The Optimum temp. for 

 digestion was approximately 20° C. Proteolysis was more rapid at 

 15° C. than at 40° C, and became somewhat less rapid when the 

 temp. was reduced from 15° C. to several degrees above 0° C, Di- 

 gestion was very energetic at temp. between 5° and 20° C. 



Flaum (19), however, demonstrated that at 0° C. the pepsin of 

 warm blooded animals gives rise to complete proteolysis of oval- 

 bumin, and that the same products are formed as at higher temp., 

 although digestion is greatly retarded. He studied the action of 

 artificial gastric juice, prepared from gastric mucosae of swine, on 

 coagulated egg white at various temp. between 40° C. and 0° C. 

 In all the experiments of a given series, the volume of gastric juice 

 and the quantity of Substrate were kept constant. In the prelim- 

 inary series, the artificial gastric juice had been rendered free from 

 acid metaprotein. The time required for the appearance of acid 



