120 SCIENCE PROGRESS 



those of anaerobic life or a yet lower term in the same genetic 

 relationship ; and that these processes, i.e. hydrolyses and 

 cleavages, are fundamental to all vital action whatsoever and 

 everywhere antecedent to the intervention of oxygen. 



8. That if oxidation were a fundamental process, life in 

 the absence of oxygen or of any oxygen-supplying materials 

 whatsoever would be inexplicable — i.e. that the "adaptation" 

 of anaerobic organisms to an oxygen "habit" is conceivable 

 and may be understood, whilst in the light of our present 

 knowledge the reverse is not. 



It is perfectly clear that the relationship between anaerobic 

 and aerobic respiration (and fermentation as well) is of the 

 closest and represents a continuum. Save between the extremes 

 of these two terms there is no sense of antagonism ; on the 

 contrary, as Bunge l observes : " Apparently from the anaerobic 

 single-celled organisms up to the most highly organised animal 

 with the liveliest need of oxygen, we have in the animal 

 kingdom every stage of transition." From being incessant, 

 the need of oxygen dwindles away until it is entirely lost. 

 At the opposite extreme we have an utter intolerance of oxygen, 

 which in turn shades away into toleration ; and this latter 

 condition may be cultivated apparently in the most strenuously 

 anaerobic types. 



It remains then simply to establish whether the one type 

 or the other is fundamental and if so which is the fundamental 

 type. If any doubt remained, it would be destroyed by the 

 fifth of the considerations noted above, viz. the establishment 

 of the actual part played by uncombined oxygen in the 

 chemistry of life. Amid a quantity of admirable work, that 

 of Verworn and his school is among the most recent and 

 most decisive. Summing up a long series of researches 

 H. Winterstein 2 concludes : 



" It must be considered that in the mechanism of tissue 

 respiration energy is primarily derived from cleavage processes 

 of a non-oxidative nature. 1 he products so formed (the suffo- 

 cation and fatigue toxins) are then as a secondary process 

 oxidised by free oxygen. This oxidation may follow imme- 

 diately on the cleavage ; it may be separated therefrom both 

 in point of time and place ; or in the case of many organisms 

 may be suppressed for a longer or shorter time (temporary or 

 continued anaerobiosis)." 



1 Zeit.f.physiol Chem. 565, 12, 1888. 



1 " U. Mech. d. Gewebsatmung," Zeit.f. allg. Physiol. 392, 6, 1907. 



