LIFE WITHOUT OXYGEN 123 



exposed to the air. 1 Of all the products of the body tissues 

 it is apparently from those which have the least supply of 

 oxygen, the most nearly anaerobic, that is the nerves, that 

 the most poisonous substances come, a fact which may explain 

 the baffling and elusive nature of neurasthenia, the typical 

 disease of persons who otherwise appear " well." 



These general considerations have received almost con- 

 clusive demonstration from the researches of W. Weichardt. 2 

 Weichardt showed that when healthy rats were put on a 

 tread-wheel and run until they dropped dead from exhaustion, 

 the sap or juice expressed from their muscles was highly 

 poisonous and produced all the effects of extreme fatigue and 

 finally death when injected into the veins of other rats. The 

 sap from control subjects showed no such toxicity. 



Weichardt found that a much larger quantity of the fatigue- 

 poison could be obtained when the exhausted muscles were 

 treated with reducing substances, whilst the poisons disappeared 

 spontaneously when the muscles were given time to rest. There 

 seems little reason to doubt from all this that " fatigue " is simply 

 accumulated poisoning and that "rest " is simply the oxidation 

 of these ermildnngs-toxine. And this is likewise the rationale of 

 the effects of "fresh" air. It is not the saturated products of 

 respiration, like carbonic acid, which, as was so commonly 

 believed, make us drowsy in a closed room, but the almost 

 infinitesimal quantities of other substances which are given off 

 from the lungs ; it would seem even from the woodwork and 

 other organic substances of a room. 3 



In the light of all this, the relaxations of anaerobic and aerobic 

 respiration become very simple and clear. In the lowest and 

 most minute of organisms the proportion of surface to volume 

 is of course at the maximum and the number of individual living 

 units interacting within the single cell is at the minimum. Some 

 interesting researches of Errera 4 and of MacKendrick 5 indicate 

 that the number of these living molecules in the simplest 

 organisms may not be over a score or more and perhaps less. 



1 Kastle and Elvove, Am. Chem. Jour. 195, 31, 1904 ; cited after Loeb, I.e. 

 * Muenchener Med. Woch. 1905, 1906, 1907. 



3 Henriet, " L' Atmosphere des Villes " and " Les Causes de 1' Alteration de 

 l'Air Confine," Revue Generate des Sciences, 183 and 483, 18, 1907. 



4 Rec. de PInst. Bot. Brux. 73, 6, 1903. 

 s Rep. Brit. Assoc. 1901, p. 808. 



