Motion in Animals and Plants and Electrical Phenomena. 37 



Csoonian Lectuee. — " On the Eelation of Motion in Animals and 

 Plants to the Electrical Phenomena which are associated with 

 it." By J. Burdon-Sandekson, M.A., M.D., F.E.S. Eeceived 

 March %— Eead March 16, 1899. 



In a Croonian Lecture which I delivered to the Eoyal Society in 

 1867 — more than thirty 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 you results which have also been 

 obtained by a graphic method, which however differs from the other in 

 that the records are written by 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 by 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 been 

 my endeavour to regard them exclusively in relation to the functional 

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

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

 with a machine that you cannot 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 physiologist. The possibility of employing it 

 depends on the circumstance that all animal organisms, and certain 

 parts of plants, possess the faculty of being awakened from a state of 

 rest to normal activity. 



Even under the most favourable conditions, the observation of this 

 transition is attended with difficulties which arise from the com- 

 plexity of the chemical and mechanical changes, and the shortness of 

 the time spent in their accomplishment. It is this crowding together 

 of chemical, thermal, and electrical phenomena into a very brief period 

 which determines the method for their elucidation, a method consisting 

 to a large extent of a determination of time-relations , i.e., of the order of 



