Diastatic Fermentations 837 



A and A' contain a little more glucose than B and B'; slight, but 

 evident difference; examinations made with great care on white paper. 



Experiment CCCCLXXII. May 25. Saliva, raw starch, and water. 

 Equal quantities in six tubes. 



A. Three are drawn out in the flame and left at normal pressure. 



B. Three at 15 atmospheres of superoxygenated air. 

 May 27. Analyses of the tubes by M. Dastre. 



A. Contain 2.2 mg.; 2.9 mg.; 1.7 mg.; an average of 2.3 mg. of 

 glucose. 



B. Contain 1.6 mg.; 1.9 mg.; 1.7 mg.; an average of 1.7 mg. of 

 glucose. 



In these experiments, the transformation of starch into sugar 

 continued to operate in compressed oxygen, but its intensity has 

 evidently diminished. 



But to obtain this result, one must not wait too long, but must 

 examine the liquids after a very few days. Otherwise, especially 

 if diastase was used, the result would be just the opposite, and the 

 compressed liquid would be richer in sugar than the other. This 

 happened, for example, in the following experiments. 



Experiment CCCCLXXIII. June 26. Raw starch in suspension in 

 water, mixed with a certain quantity of diastase. Well shaken; placed 

 in 2 tubes: 



A. Normal pressure. 



B. 15 superoxygenated atmospheres. 



July 21. A, 5 cc. reduce 25 drops of copper reagent. 



B left under compression till then; 5 cc. reduce 40 drops. 



In both there is still some starch. 



Experiment CCCCLXXIV. March 1. Saliva, raw starch, water, 

 equal quantities in 12 tubes: 



A. Six are drawn out in the flame and left at normal pressure. 



B. Six are placed at 15 superoxygenated atmospheres. 

 March 28. Analysis of the tubes by M. Dastre. 



A. 2 tubes contain quantities of glucose proportional to the num- 

 bers 45 and 39; hence, an average quantity of 1.7 mg. 



B. 3 tubes analyzed contain quantities of glucose proportional to 

 the numbers 111, 119, 115; hence an average quantity of 4.6 mg. of 

 glucose. 



That is easily explained; the diastase which had been left in the 

 air had altered a little, whereas that which was under compression 

 had kept its properties and continued to act. 



2. Pepsin. 



Experiment CCCCLXXV. February 16. Boudaut pepsin; three 

 tubes, in each of which are placed 2 grams of pepsin with 5 cc. of 

 distilled water. 



