For this purpose I have modified the experiment previously described in the way that after every introduction into the blood of oxygen-free saline solution and after the injection of strychnine, the artificial circulation was stopped so that stagnation of the oxygen-free saline solution took place in the vascular system. The processes then occurred in exactly the same manner with the exception that the state of non-irritability appeared somewhat earlier. If after the beginning of complete depression artificial circulation with oxygen-free saline solution was again started, a certain degree of recovery took place within one or more minutes. The stimuli were once more effective and produced a number of contractions. At times, several single contractions, following each other in more or less quick succession, could be brought about. But complete recovery or the appearance of even incomplete tetanic convulsions was never again obtained, whereas by the introduction of oxygen complete recovery could at once be brought about. If, however, the circulation with oxygen-free saline solution was continued, irritability gradually decreased. The refractory periods after the individual stimuli became longer, and in spite of continuous artificial circulation irritability _again_ disappeared. The experiment shows that by the circulation of oxygen-free solution irritability can simply be reduced up to a certain degree. This partial restitution is produced by washing out the depressing metabolic products. Being desirous to verify the results of this investigation with greater exactitude I have requested _Dr. Lipschütz_[143] to repeat the experiments, taking the utmost possible precaution in respect to the absolute exclusion of oxygen. _Lipschütz_ has tested the normal saline solution made oxygen free with the sensitive _Winkler_ method, in which the slightest trace of oxygen is shown by the oxydation of manganous chloride to manganic chloride in which the latter in a saline solution sets free an amount of iodide from iodide of potassium corresponding to that of the consumed oxygen. These experiments of _Lipschütz_ have shown that even with the absolute exclusion of the slightest trace of oxygen a partial recovery can be brought about by artificial circulation. There can be, therefore, no doubt that recovery is actually founded on the removal of the depressing asphyxiation substances by artificial circulation. Moreover _Fillié_[144] has previously succeeded in the laboratory at Göttingen in obtaining by the same methods a corresponding result for the nerve. In both cases the experiments are extremely complicated and must be carried out with the most painstaking care. The depressing influence of the asphyxiation products need not be regarded as a specific effect of poisoning. It can be solely an expression of mass relations, if we assume that the anoxydative decomposition is controlled by a chemical