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The Effect of Heat upon the Electrical State of Living Tissues. 

 By A. D. Waller, M.D., FR.S. 



(Received February 20,— Read March 4, 1909.) 

 I. Of Muscle. 



The question whether the sudden application of heat acts as a physiological 

 stimulus to nerve and muscle naturally leads on to a study of the effect of 

 local heat upon the electrical state of living tissues. I have done this 

 (1) upon muscle, (2) upon nerve, and (3) upon the skin. As far as I know, 

 the only tissue hitherto tested in this respect is muscle.* 



Du Bois-Reymond first,f then Worm-MiillerJ in more detail, observed that 

 a muscle dipping in an indifferent fluid that was gradually heated and led off 

 to the galvanometer from the fluid and from the undipped muscle exhibited,, 

 with rise of temperature, positivity followed by negativity of the undipped 

 portion. Hermann, in 1870,§ flatly contradicts this statement, but in the 

 following year|| gives an account of experiments from which he concludes 

 that warmer portions of living muscle are positive in relation to cooler 

 portions, i.e. that differences of temperature in the muscle give rise to 

 a special electromotive force (eine besondere elektromotorische Kraft). But 

 the protocols of his experiments, especially when they are plotted as curves, 

 are not very convincing. The question is one that requires to be carefully 

 re-tested. None of the experiments quoted affords any conclusive proof 

 that the influence of rise of temperature upon muscle currents were true 

 physiological effects apart from physical (thermo-electric) changes. 



The method employed in the present series of observations was as indicated 

 in the following representative experiment. 



* I learn that Engelmann, in 1872, examined the influence of temperature upon skin- 

 currents, obtaining with rise of temperature a negative variation of the normal current, 

 ' Pfliiger's Archiv,' vol. 6, p. 138. 



f Du Bois-Reymond, ' Untersuchungen tiber Thierische Elektricitat,' vol. 2, p. 178 ; 

 ' Gesammelte Abhandlungen,' etc., vol. 2, p. 202. 



\ ' Worm-Midler, ' Versuche iiber die Einflusse der Warme auf die elektromotorischen 

 Krafte der Muskeln und Nerven,' Wiirzburg, 1868. 



§ Hermann, "Versuche liber den Verlauf der Stromentwicklung beim Absterben." 

 'Pfliiger's Archiv,' vol. 3, p. 43, 1870: " Genau bei 40° ... . entwickelt sich ein im 

 lebenden Muskel aufsteigender Strom. Die absterbende Muskelsubstanz erlangt also ihre 



Negativitat gegen die lebende in dem Momente der Erstarrung Eine (nicht 



thermoelektrische) Positivitat der erwarmten Substanz im Sinne Worm-Muller's existirt, 

 nicht." 



|| Hermann, same title, 'Pluger's Archiv,' vol. 4, p. 163, 1871. 



