214 CARBOHYDRATE-SPLITTING FERMENTS 



with toluol in a special extraction apparatus in the cold, and 

 thus freed of fats and lipoids. At this stage the tissue con- 

 sists of a fine pulverulent mass which includes proteins and 

 ferments in soluble and well preserved form, and affords an 

 excellent and well adapted supply of material for quantita- 

 tive fermentation studies. If a weighed amount of the pow- 

 dered tissue be rubbed up with physiological salt solution 

 in a mortar, a very fine emulsion is obtained which sediments 

 only very gradually, and may be subdivided with graduated 

 pipettes; and is very well suited for employment in com- 

 parative study with similarly prepared powdered tissue 

 from other source. 



In applying this method to determination of the diastases 

 in tissues, Starkenstein, 68 in the laboratory of J. Pohl, found 

 it essential to keep up a continuous agitation so as to insure 

 adequate contact of the ferment and the substrate, lest the 

 tissue protein, quickly coagulating at room temperature, 

 take up by mechanical adsorption both starch and ferment, 

 and in this way be sure to occasion too low a result in the 

 quantity of the latter. Thereafter the actual estimation 

 may be conducted by the method of Wohlgemuth. 



From what has been said we may be satisfied that many 

 of the older statements as to the effect of various physio- 

 logical and pathological factors upon the quantity of 

 diastase in the tissues have but doubtful value. 



Hepatic Diastase. As for the liver, it can be finally said 

 that the constantly recurring doubt as to whether its vital 

 diastasic activity is really due to an enzyme, has been con- 

 clusively settled. 69 The present attitude is to regard the 

 quantity of diastase in the liver as subject to a nervous regu- 

 lation ; and the tendency is to relate starvation diabetes of 

 the dog, as well as the glycosurias following brain injuries, 

 Claude Bernard's puncture, or administration of adrenin, 



68 E. Starkenstein (J. Pohl's Lab.), Biochem. Zeitschr., 24, 191, 1910. 

 Consult Literature in F. Pick, Hofmeister's Beitr., 3, 163, 1902. 



