322 



where, consequently for the obligatous anacrobics, too. That is, for tliem also, to re- 

 t'ügnise free oxygen as a necessity for existence. 



This opinion has the more weight iiow that it has been proved how easily may be 

 shown tliat they iiot only use free oxygen but if possible, seek it and that it may pro- 

 nicte even such important functions as growth and nidbility. 



Without doubt, this points to something more than »use«, albeit the term »want« 

 goes perhaps too far. As it is however a fact that the obligatous anaërobics can pro- 

 duce thousands of new generations without a renewed contact with free oxygen, the 

 hypothesis demands the acceptance of a peculiar exciting action of the free oxygen, 

 stored up as a provison in the body of the bacteria. 



This action cannot be compared to that of kalium, or of magnesium, or of the 

 other elements necessary for life in small quantities. In the first place, because the 

 latter must be present in quantities of another order, quantities gigantic compared to 

 that of the oxygen provision; secondly and especiaily, because these elements may be 

 withdrawn from the most different chemical compounds. The very necessity of the 

 oxygen being free, causes the difficulty of giving a definite representation of its func- 

 tion. Some light would go up if it could be proved, that in the food a loosely bound 

 form of oxygen might occur, accessible to the anaërobics, and Pasteur has indeed sup- 

 posed that the oxygen, which is found in beer wort, and cannot be separated from it 

 by pomping or boiling, makes the anaërobiosis of beer yeast possible. 



Facts are however not in accordance with this hypothesis. Now, as in the case of 

 beer yeast and the other facultative anaërobics, we are obliged to admit the existence 

 of a store of free oxygen in the cell itself, which, in a way hitherto unexplained, 

 makes a temporary anaërobiosis possible, analogy, supported by the observations here 

 described, leads to the same concKision for the obligatous anaërobics. 



