On Relationship between Staircase phenomenon and fatigue. 291 



of the reaction is the catalyst is that the velocity, at first 

 comparatively low, rapidly increases and then, after attaining 

 a maximum, declines as the reaction approaches equilibrium. 

 The maximum velocity occiirs when the concentration of the 

 catalysing product (in monomolecular reactions) has reached 

 half its maximum value, that is, referring to the equation 

 given above, when a; = ^/^A. The velocity of a reaction which 

 is not autocatalysed, on the contrary, falls from the beginning 

 of the reaction to the end. 



//. The Biochemical Significance of the „Staircase" phenomenon 

 and of Fatigue in Muscle. 



It is well-known that when a muscle is repeatedly stimu- 

 lated either directly or indirectly through its nerve, the first 

 few contractions gradually and with considerable regularity 

 increase in height until they reach a maximum for a given 

 Stimulus. This phenomenon, to which the name of ,, treppe" 

 or the „staircase" was given by Bowditch^), has been the 

 subject of considerable investigation and conjecture.^) Of a 

 similär nature is the phenomenon of ,, Summa tion of Stimuli", 

 whereby a Stimulus of insufficient strength to give rise to a 

 response may be made, by repitition, to elicit a response.'^) 



It is to Waller we owe the Suggestion that the „stair- 

 case" is, in reality, due to the production of COg in the 



1) Bowditch, Ber. d, Math.-phys. Klasse d. kgl. Sachs. Ges. d. 

 Wiss. 23, 652, 1871. — Arbeiten aus der Physiol. Inst, zu Leipzig 6, 

 139, 1871. 



2) Tiegel, Arbeiten aus der Physiol. Anst. zu Leipzig 1875, 

 quoted after Burdon-Sanderson, Schäfers Text-book of Physiol. Edin- 

 burgh 2, 381, 1900. — Marey, Joum. de I'Anat. et de la Physiol. 3, 

 225, 1866. — Roßbach and Harteneck, Arch. f. d. ges. Physiol. 15, 

 1, 1877. — Romanes, Phil. Trans. Roy. Soc. London 167, 659, 1877. — 

 „Jellyfish, Starfish and Sea-urchins." Int. Sei. Ser. 1886, 56. — Minot, 

 Joum. of Anat. and Physiol. 12, 297, 1877. — Sewall, Joum. of 

 Physiol. 2, 164, 1879. — Buckmaster, Arch. f, Anat. u. Physiol., 

 Physiol. Abt. 1886, 459. 



3) Helmholtz, Quoted aftei Burdon-Sanderson, Schäfers 

 Text-book of Physiol., Edinburgh 2, 380, 1900. — Riebet, Physiologie 

 des muscles et des nervs, Paris 1882. — Engelmann, Arch. f. d. 

 ges. Physiol. 3, 280, 1870; 29, 453. 1882. 



19* 



