BIOLOGICAL EXPERIMENTS. 287 



electricity in nervous and muscular changes. " Nerve force," like 

 " vital force," is a word which simply expresses our ignorance, but 

 if the tenor of all experiments of late years points in the direction 

 of " nerve force " being simply a form of electricity, we are 

 dealing with something real, the laws of Avhich can be understood. 

 I will give the account of Dr. Waller's experiments,* chiefly in his 

 own words. 



He says : — " Our new^ bit of knowledge is about the human 

 heart, not in a metaphysical or figurative sense, not its motives, 



but only its action Put into a single sentence, I am 



going to describe how^ the heart of man can be said to act as an 

 electrical organ, and what we learn from such an action. 



" It is a well-known fact that every beat of the heart is accom- 

 panied by an electrical disturbance. The nature of this 

 disturbance has been studied and understood in cold-blooded 

 animals, and in the laboratory of St. Mary's Hospital an investiga- 

 tion has been carried out to learn whether warm-blooded animals 

 show similar electrical disturbances. These latter experiments 

 seem to indicate that, whilst the electrical disturbances appear to 

 be similar in the two classes of animals, they are not identically 

 so, and that the contraction, which at each beat of the cold- 

 blooded heart runs down from the base to the apex, runs in the 

 opposite direction in the warm-blooded heart." 



" Led on from thought to thought," continues Dr. Waller, " it 

 occurred to me that it should be possible to get evidence of 

 electrical action on man by connecting, not the heart itself, which 

 is obviously impossible, but parts of the surface of the body near 

 the heart with a suitable instrument. Having verified this 

 supposition, the next step was to see whether the same evidence 

 could be obtained by connecting the instrument with parts of the 

 body at a distance from the heart, as the hands or feet. The 

 answer w^as satisfactory. Finally, I tried whether two people 

 holding hands and connected with the instrument gave evidence 

 of electrical shocks through each other, and I found they did." 



Dr. Waller then proceeded to explain in detail the second step 

 in these experiments, namely, an analysis of the results which are 



* Bnizsk Medical Journal, Oct. 6th, 1888. "Introductory Address on 

 the Electro-motive Properties of the Human Heart," by A. D. Waller, M.D. 



Journal OF Microscopy and Natural Scirnce. 



New Series. Vol. II. i88q. u 



