836 Experiments 



placed in a closed tube January 18, was still active February 12; 

 although a very small orifice was left open in the tube then, the 

 saliva still had considerable activity May 17. 



The same thing is true of the pancreatic juice and in general of 

 the soluble ferments, which even resist beginning putrefaction. 



But now, even if it is preserved in compressed air, does the 

 ferment retain its activity there? And does it act there with more 

 or less energy than at normal pressure? 



Experiments will give the answer. I call attention to the fact 

 that I took raw starch in suspension in water, because cooked 

 starch is transformed instantaneously on contact with saliva. 



Experiment CCCCLXVIII. July 18. My saliva, filtered, is mixed 

 with a certain quantity of water holding raw starch in suspension; 

 it is mixed carefully and placed in 3 open tubes: 



A. Left at normal pressure. 



B. Taken to a half-atmosphere. 



C. At 8 superoxygenated atmospheres. 



The tubes and apparatuses are placed in identical conditions of 

 temperature. 



July 20. Withdrew the tubes, filtered the liquids rapidly, and 

 tested them with Fehling's reagent. 



A. 5 cc. reduce from 75 to 85 drops of copper reagent. 



B. 5 cc. reduce from 65 to 75 drops of copper reagent. 



C. 3 cc. reduce from 50 to 60 drops of copper reagent. 



Experiment CCCCLXIX. May 26. Filtered saliva, mixed with raw 

 starch in suspension in an equal volume of water. The liquid, well 

 mixed, is placed in equal quantities in 2 tubes, one of which, A, is 

 left at normal pressure, the other, B, is subjected to 15 superoxygen- 

 ated atmospheres. 



June 3. A evidently contains much more sugar than B. 



However the deposit at the bottom of tube A is colored an intense 

 blue by iodine, whereas that in B gives only a greenish discoloration. 



Experiment CCCCLXX. January 20. Saliva, raw starch, and water. 

 Well mixed and placed in tubes. We make sure that the mixture 

 contains no glucose. 



A. At normal pressure, covered with an inverted paper cone. 



B. At 21 atmospheres of superoxygenated air. 

 Both are placed in the drying-oven, at 30 degrees. 

 January 25. Tested with copper reagent. 



A. 7 cc. reduce 35 drops. 



B. 7 cc. reduce only 14 drops. 



Experiment CCCCLXXI. March 22. Saliva, raw starch, and water. 

 Mixture placed in tubes. 



A, A'. At normal pressure. 



B, B'. At 9 superoxygenated atmospheres. 

 March 24. Tested with copper reagent. 



