RELATION OF MOTION IN ANIMALS AND PLANTS TO 

 THE ELECTRICAL PHENOMENA WHICH ARE ASSOCI- 

 ATED WITH IT/ 



By J. Burdon-Sandersox, :\I. A., M. I)., F. R. S. 



In a Croonian lecture which I. delivered to the Royal Society in 

 1867 — more than thirt}^ years ago — I exhibited a number of diagrams 

 of graphic records, in evidence of the mechanical relations which I 

 then sought to establish between the movements of the heart and those 

 of respiration in the higher animals. 



I have to-day to bring before vou results which have also been 

 obtained by a graphic method, which, however, diflers from the other 

 in that the records are written b}' light, and not by pen on paper; that 

 the time taken in recording is measured in thousandths of seconds, not 

 tenths; and finally, that the events recorded are not the movements of 

 the chest or heart, but the electrical changes which, as will be shown, 

 are found to associate themselves with all manifestations of functional 

 activity in living organisms, whenever these take place under condi- 

 tions which admit of their being investigated. 



Our purpose is to consider the relation of two coincident and con- 

 current processes, with reference to which we make at the outset the 

 assumption that one is functional, the other concomitant, using the 

 word "function''' in the biological sense to imply the doing l)y an 

 organ of the work for which it is adapted. In the observations which 

 I have made from time to time during the last twenty years relating 

 to the electrical phenomena of plants and animals, it has always })een 

 my endeavor to regard them exclusively in relation to the functional 

 activity of the structures in which they manifest themselves. In inves- 

 tigating the function of a living organ or organism, you have to do 

 with a machine that you can not take to pieces, and it is often the best 

 way to observe how, after its action has been arrested, it goes on again. 

 To do this under experimental conditions is one of the most frequently 

 used methods of the ph\'siologist. The possibility of employing it 



* Croonian lecture before Royal Society of London, March 16, 1899. Reprinted 

 from Proceedings of the Royal Society, Vol. LXV., No. 413, pp. 37-64. 



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