250 IRRITABILITY 



asphyxiation the air-ether current in the latter chamber was 

 replaced from time to time by an ether-nitrogen current, and 

 then by one of pure nitrogen, so that the narcosis was interrupted 

 without the entrance of oxygen being possible in the mean time. 

 During this suspension of the narcosis, the nerve recovered each 

 time in nitrogen, its irritability again increasing and its capa- 

 bility of conduction returning with every test. However, re- 

 covery showed itself as less and less complete. Finally irrita- 

 bility had sunk so low that the capability of conduction disap- 

 peared entirely. At the end of the experiment as control, nitro- 

 gen was displaced by air in the two chambers and in both nerves 

 recovery took place. 



In both cases recovery could only be brought about by an intro- 

 duction of oxygen. From the sum of all these experiments it 

 results that during narcosis in air the nerve, even when a suffi- 

 ciency of oxygen is present, gradually asphyxiates and loses 

 its capability of conduction, and this in about the same length 

 of time as the other nerve in pure nitrogen. These investiga- 

 tions furnish two important facts for the theory of narcosis. 

 First, that in narcosis living substance becomes asphyxiated not- 

 withstanding the presence of an ample oxygen supply, and 

 secondly, that asphyxiation occurs in the same time, or some- 

 what more rapidly, in pure nitrogen under otherwise similar 

 conditions than without narcosis. In other words, it is shown 

 that the breaking down processes of metabolism continue in nar- 

 cosis as anoxydative disintegration. In narcosis, therefore, 

 asphyxiation takes place with approximately the same or a some- 

 what greater rapidity than that in an oxygen-free medium. 



The fact here established explains in the simplest manner the 

 often described observation that in the human being and in mam- 

 mals during prolonged anaesthesia typical products of insufficient 

 combustion, such as fatty acids, lactic acid and above all aceton, 

 in not inconsiderable quantities are eliminated, as the case may 

 be, by the urine or the respiratory air.^ If, as has been shown by 



1 For the very extensive literature on this subject see Reicher: "Chemisch- 

 experimentelle Studien zur Kenntniss der Narkose." Zeitschr. f. klinische Medicin 

 Bd. 65, 1908. 



