176 IRRITABILITY 



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. Lipschiitz^ to repeat the experiments, taking the 

 utmost possible precaution in respect to the absolute exclusion of 

 oxygen. Lipschiits has tested the norn>al 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 solu- 

 tion sets free an amount of iodide from iodide of potassium corre- 

 sponding to that of the consumed oxygen. These experiments 

 of Lipschiits 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 depress- 

 ing asphyxiation substances by artificial circulation. Moreover 

 Fillic' has previously succeeded in the laboratory at Gottingen in 

 obtaining by the same methods a corresponding result for the 

 nerve. In both cases the experiments are extremely compli- 

 cated 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 equilibrium between 

 masses capable of disintegrating and products of the disintegra- 

 tion. It is not possible to give any detailed account as to the part 

 taken by accumulating asphyxiation substances in the prolonga- 

 tion of the refractory period. Indeed, we must for the present 

 relinquish the attempt to delimitate quantitatively the part taken 

 by the individual constituent processes in the symptoms of de- 

 pression resulting from the deficiency of oxygen. We can merely 



1 Alexander Lipschiits: "Ermiidung und Erholung des Ruckenmarks." Zeitschr, 

 f. allgem. Physiologic Bd. VIII, 1908. 



2 Fillie: "Studien uber die Erstickung und Erholung des Nerven in Flussigkeiten." 

 Zeitschr. f. allgem. Physiologie Bd. VIII, 1908. 



