In like manner _Fröhlich_[213] has established the same fact for the nerve. The period of asphyxiation for the nerve in a nitrogen-ether mixture is approximately the same as in pure nitrogen. Analogous experiments have been carried out in amœbæ by _Ishikawa_.[214] Here also it has been shown that living substance becomes asphyxiated in narcosis and can finally recover only when oxygen is supplied. In more than a hundred experiments _Ishikawa_ has, however, obtained the uniform result that amœbæ asphyxiate rather sooner in narcosis than in pure nitrogen. The most striking experiments are those which _Heaton_[215] has carried out on the nerve. Using both sciatic nerves of the same frog, he passed each one through a separate glass chamber, as previously described, and laid the central stumps projecting from the chamber over a pair of platinum electrodes, while the stretch within was likewise placed on platinum electrodes. The muscles served as indicator of the capability of conduction and irritability. The alterations thereof were tested by the ascertainment of the threshold of stimulation. The nerve in the _one_ chamber was then subjected to a pure nitrogen current, that in the _other_ merely to one of pure air with ether. In order to test the degree of 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 capability of conduction returning with every test. However, recovery showed itself as less and less complete. Finally irritability had sunk so low that the capability of conduction disappeared entirely. At the end of the experiment as control, nitrogen was displaced by air in the two chambers and in both nerves recovery took place. [211] _Bondy_: “Untersuchungen über die Sauerstoffspeicherung in den Nervencentren.” Zeitschr. f. allgem. Physiol. Bd. III, 1904. [212] _Baglioni_: “Bezichungenzwishen physiologischer Wirkung und chemischer Constitution.” Zeitschr. f. allgem. Physiologie Bd. III, 1904. [213] _Fr. W. Fröhlich_: “Zur Kenntniss der Narkose des Nerven.” Zeitschr. f. allgem. Physiologie Bd. III, 1904. [214] The experiments of _Ishikawa_ have not as yet been published. [215] _Trevors B. Heaton_: “Zur Kenntniss der Narkose.” Zeitschr. f. allgem. Physiologie Bd. X, 1910.