reaction is lost, being certain of this by the injection of a weak dose of strychnine, and if now a cessation of the narcosis is brought about by the transfusion of oxygen-free saline solution, the centers of the animal recover completely within ten to fifteen minutes, as shown by typical strychnine tetanus. If a nerve is placed in a gas chamber through which a mixture of nitrogen and ether is allowed to flow until irritability is greatly decreased, and is then displaced by pure nitrogen, irritability increases more or less completely according to the time which has passed from the beginning of asphyxiation. This investigation proves that living substance, even after the deepest narcotic depression, may recover on cessation of the narcosis, although in an entirely oxygen-free medium. _Fröhlich_, _Bondy_ and _Heaton_, by the methods of their experiments above described, have proved this fact in a great number of instances. On the other hand, _Ishikawa_ could not observe a pronounced recovery in amœbæ from narcosis in pure nitrogen. But it is possible that here the difference is perhaps merely quantitative. What position should be taken in the face of these facts? Does recovery of a deeply narcotized tissue in an oxygen-free medium really make it difficult to suppose that narcosis is the result of an acute suppression of the processes of oxydation? On closer view, it will be found that this difficulty is merely apparent. In reality it is quite possible to bring these facts into harmony with the assumption that narcosis consists in a suppression of these processes. If one proceeds from the supposition that living substance possesses a certain, even though merely a small supply of oxygen in its interior, then it is at once evident that a more or less complete recovery of irritability from narcosis depression is possible, even in an oxygen-free medium. It can take place at the cost of the oxygen still present in the living substance and which during the narcosis, on account of the suppression of the oxydation processes, could not be consumed. If the presence of a certain oxygen reserve in living substance is entirely set aside and a different explanation sought for the primary continuance of irritability after a complete withdrawal of the oxygen supply from without, the great difference of time in the setting in of the depression in narcosis and that of the complete elimination of the oxygen supply from without would make it necessary to assume the processes occurring in narcosis are entirely different in nature. The explanation that narcosis is the result of suppression of the oxydative processes would indeed be out of the question in such a view.