ELECTRICAL CHANGES IN TISSUES 



653 



a 



FIG. 209. 



a. Electrical change of the dog's ventricle in situ. Led off by contacts on apex and base. 



Warm air for artificial respiration. 



Simple diphasic response, base becoming negative first. Time, Jth sec. above. 

 6, Reversed response with cold air for respiration. 



In middle curve, a trace of a preliminary short base negativity. 

 c, An intermediate stage between a and b. 

 The heart beats are indicated by a tambour giving the tracing between the time signal, and the 



electrical change, and are not to be taken as showing anything but the fact of the occurrence 



of a heat. 



Note that although the electrical changes were opposite in sign in a and 6, no difference was to he 

 noticed in the nature of the beat, so far as could be judged by the eye. 



(Bayliss and Starling, 1892, 1, Figs. 7, 6, arid 5.) 



