Diastatic Fermentations 835 



1. Saliva and Diastase. 



The zymotic fermentation upon which I was to experiment most 

 frequently is that by which diastase transforms starch into glu- 

 cose. Besides the considerable interest presented by this phe- 

 nomenon, which plays so great a part in the digestion of animals 

 (saliva and pancreatic juice) , in their nutrition (hepatic glyco- 

 genosis), that of plants and germination, I was influenced by the 

 ease with which one can measure its effects exactly. 



The first question to be settled was whether the diastatic ferment 

 is killed by oxygen at high tension, as the organic ferments so 

 surely are. The following experiment will give the answer. 



Experiment CCCCLXV. June 26. Diastase is dissolved in a little 

 water and placed in two tubes: 



A: normal pressure. 



B: at 15 superoxygenated atmospheres. 



July 21. Decompressed B, which has no odor and has retained the 

 most energetic transforming power, whereas A smells bad and no 

 longer has any effect on cooked starch. 



Experiment CCCCLXVI. February 16. Diastase and water in a 

 tube drawn out. Placed at 15 atmospheres of superoxygenated air. 



May 5. Decompressed, has retained all its effect. I make a new 

 solution of diastase in a tube which I close with a flame, as 1 also do 

 with the first. 



May 17. The diastase which was compressed still acts upon starch; 

 it has no odor. The other has a butyric odor and no strength left. 



So diastase, far from being spoiled by oxygen at high tension, 

 is preserved perfectly in it. It even appears that it remains power- 

 ful almost indefinitely, in all probability because of the destruc- 

 tion by the compressed air of the organic ferments, which would 

 have caused it to putrefy at normal pressure. 



We get the same result when we experiment upon, not pure 

 diastase dissolved in water, but the complex mixture which con- 

 stitutes the buccal saliva. Example: 



Experiment CCCCLXV II. July 21, 1874. Human saliva diluted with 

 water and placed in a matrass drawn out in a flame, and subjected 

 to 15 atmospheres of superoxygenated air. 



July 30, I make the decompression and close the end of the tube 

 which was drawn out. 



January 18, 1875. This saliva, which has no odor and appears 

 quite normal, neutral to reagents, has a powerful transforming effect 

 upon starch cooked in glucose. 



So saliva is preserved in compressed air; but I must confess 

 that it keeps very well in open air also. Unfiltered human saliva, 



