382 



M'Dowall 



the polarising action of metal electrodes is avoided. The apparatus was 

 arranged so that it could be immersed in a vessel of water and raised or 



Fig. 1.— Diagram of apparatus employed. 



A, B, muscle cliamber in two parts, which fit together exactly ; C, hole in the bottomof 

 part A, through which one end of the muscle strip, E, is passed : A and B are filled 

 with Ringer's solution ; D, D', platinum electrodes in the Rini^er ; F, thermometer 

 indicating the temperature of the fluid ; G, muscle lever ; K, K, outer vessels form- 

 ing a water jacket to the muscle chamber; H, H, inlet tube for passing either 

 warmed or cooled water into the water jacket; I, I, siphon for drawing water oflf: 

 L, lamp ; M, gutta-percha covered wire passing through water jacket. 



By the above arrangement any current passing from D to D' must traverse thelwhole 

 thickness of the muscle. 



lowered in temperature at will, the temperature being recorded at about 

 1 cm. distance from the muscle (fig. 1). The following points have been 

 made out in the course of these experiments : — 



