LIFE WITHOUT OXYGEN 117 



2. "For all forms of protoplasm oxygen above a certain 

 tension is an intense poison. For some forms this tension may 

 be no more than a very small fraction of an atmosphere ; for 

 others it is from three to four atmospheres. 



3. " Atmospheric oxygen has little oxidising power; whereas 

 protoplasm brings about oxidation of the most radical nature 

 and is comparable in its oxidising powers to the most intense 

 chemical oxidising agents. 



4. " Hydrogen is evolved as a gas by a great variety of 

 bacteria and moulds. 



5. " Many forms of protoplasm such as the anaerobic bacteria 

 are able to bring about intense oxidations in the absence of 

 atmospheric oxygen." 



Matthews adds : 



" The studies of Armstrong, Dixon and others on the pro- 

 cesses of slow and explosive oxidations and combustions throw, 

 in my opinion, a remarkably clear light on protoplasmic respira- 

 tion. These authors have shown that in ordinary oxidation the 

 presence of some water is necessary to the oxidation. Phos- 

 phorus in a perfectly dry state will not ignite in dry air. 

 Armstrong concludes that the primary oxidation in all these 

 cases is not brought about by the gaseous oxygen but by the 

 water. The atmospheric oxygen acts the part only of a de- 

 polariser to take care of the nascent hydrogen formed from the 

 water. 



" The same hypothesis will explain protoplasmic respiration 

 and at once makes clear the identity of anaerobic and aerobic 

 respiration. The following theory of respiration is founded in 

 part on Armstrong's work : 



" The real respiration of all forms of protoplasm, both aerobic 

 and anaerobic, is brought about not by the oxygen of the air 

 but by that of the water. The hydrogen set free from the water 

 combines with other elements of the protoplasm, thus keeping 

 it reduced ; it also combines with the oxygen of the air if this is 

 present to form water ; and in the absence of oxygen it may 

 escape as free hydrogen. 



" The only difference between anaerobic and aerobic respira- 

 tion is that the anaerobic protoplasm is so powerful a reducing 

 agent that it is able to drive hydrogen out of the water, thus 

 oxidising itself without the aid of atmospheric oxygen to act as a 

 depolariser." 



Primarily then, in Matthews' view, " respiration is the dis- 

 sociation of water accompanied by the liberation of hydrogen." 



Practically the same view is sustained by Barnes from the 

 botanical side. In view of the fact that the word " respiration " 



