On Relationship between Staircase phenomenon and fatigue. 293 



an autocatalysed chemical reaction, under similar conditions, 

 when one of the products of the reaction is the catalysor. 

 When, in addition, we recollect that it has been shown by 

 direct experiment that substances (COg Lactic acid, KHgPO^) 

 produced during the activity of muscle do increase its irrita- 

 bility and the magnitude of its response to Stimuli and that, 

 furthermore, these same substances in larger amount or after 

 acting upon the muscle for a longer time also diminish or 

 even abolish its irritability and the magnitude of its response 

 to Stimuli^) there can, I think, remain very little doubt that 

 the chemical processes underlying muscular activity 

 are of the nature of autocatalysed reactions of that 

 type in which one or more of the products of the reaction 

 act at the same time as catalysors of the reaction. 



In the central nervous System we meet with phenomena 

 which are in many respects analogous to the ,, staircase" 

 phenomenon and subsequent fatigue in muscles. We know that 

 an increase in the COg tension of the blood supplied to the 

 brain at first accelerates and later, if the increase in CO, 

 tension be sufficiently great, inhibits the rhythmic discharge 

 of impulses from the respiratory centre or centres,*) and it is 

 by no means improbable, from a consideration of investigations 

 to be described in this paper, that COg is one of the products 

 of the activity of the nerve-cells in the central nervous System. 

 It appeared of interest, therefore, to determine whether, in the 

 central nervous System as in muscle, substances similar to those 

 produced during the Stimulation of the nerve-cells accelerate 



1) Ranke, Quoted after Burdon-Sandßrson, Schäfer's Text- 

 book of PhysioL, Edinburgh 2, 389, 1900. — Mos so, Trans. Internat. 

 Med. Cong. Berlin 1890. — „Fatigue", Transl. by Drummond and 

 Drummond, London 1904, Chapter 5. Cf. in this connection, an inter- 

 esting investigation by Winterstein, Arch. f. d. ges. Physiol. This ob- 

 server has shown that if the fonnation of lactic acid in the muscle be pre- 

 vented by subjecting the muscle to a high pressure of oxygen the onset 

 of rigor, due to excessive Stimulation, is delayed or altogether prevented. 



8) Haidane and Priestly, Joum. of Physiol. 32, 225, 1906. — 

 Cf. Starling Croonian Lecture 1905 , CoUected papers from the 

 Physiological Laboratory of üniversity College London 14, Nr. 1, 

 1905—06. 



