Chapter VI 



EFFECT OF CHANGES IN BAROMETRIC 



PRESSURE ON FERMENTS, POISONS, 



VIRUSES AND ANTOMICAL ELEMENTS 



The admirable researches of M. Pasteur have shown that the 

 phenomena known by the name of fermentations belong to two 

 very distinct categories. Some are related to the development of 

 microscopic living beings, vegetable or animal, such as alcoholic, 

 acetic, and butyric fermentations and putrefaction. Others are 

 caused by the action, still not understood, of substances produced 

 by living beings, but soluble in water, and keeping their power 

 after being isolated from the liquids in which they existed, and 

 even after being dried; such is the transformation of starch into 

 glucose under the influence of animal or vegetable diastase; or the 

 formation of the essence of bitter almonds by synaptase acting on 

 the amygdalin, etc. 



It was quite natural to inquire whether changes in the baro- 

 metric pressure (we can now say in the tension of the ambient, 

 oxygen) would have any appreciable effect on these phenomena. 

 In the first place, for true fermentations, it was simply a question 

 of whether an agent which according to its concentrations is both 

 so necessary and so dangerous as oxygen, the lack of which ends 

 life and the excess of which kills animals and plants which are 

 visible to the naked eye and are of a rather complex anatomical 

 organization, would have no effect upon microscopic beings, re- 

 duced to cellular structure. As for the false fermentations, the 

 zymotic fermentations, since they surely play a very great part in 

 the chemical phenomena of metabolism in all living beings, it was 

 interesting to find out whether oxygen tension could act upon them. 



Poisons and viruses, which resemble the ferments of these two 

 classes from so many points of view, also deserved to be tested. 



799 



