172 



SECTIONAL ADDRESSES 



positive or negative work. The following figures from experiments 

 which I have carried out with Miss Bedale and G. McCallum show 

 clearly this diminution in efficiency as the static element in the work 

 is increased : — 



Table V. 



Another series of experiments carried out with Burnett in another 

 fashion led to the same conclusion. 



Very closely allied with the rate of working is the rhythm with 

 which the work is performed. Although they are not identical pheno- 

 mena, they are so closely related that the habit of work may be con- 

 sidered along with rhythm. Sir Charles Shen-ington and Graham 

 Brown have both shown very definitely, in connection with their work 

 on reciprocal innervation, that a rhythmic phenomenon may be evoked 

 in muscle by the appropriate balance of antagonistic stimuli. Graham 

 Brown holds that this rhythmic action is one of the most fundamental 

 properties of the nervous system. Everyone is well aware that once 

 a rhythm, or the proper co-ordination in the play of a set of muscles 

 in the performance of some definite act, is mastered, not only is the 

 energy expenditure reduced by the exclusion of numerous extraneous 

 muscular activities, but there is an actual enhancement of the ease with 

 which we perform the specified act. Willingly or unwillingly, those 

 who have to do much repetitive work, be it playing golf, a musical 

 instrument, or working a machine, soon appreciate the fact, when they 

 think about it at all, that their best and easiest results are obtained 

 under certain very definite conditions. To take a single example, the 

 work of forward progression or walking is performed most easily 

 when we adopt our own gait. It is not a mere question of rate. In 

 a series of experiments which I carried out with IBurnett, the subject, 

 working on a specially geared ergometer, was allowed tO' select his own 

 rate of working, the load being varied from nothing to 4 kilos. At 

 each change of load the subject was directed either to work rapidly 

 or very slowly, and after a period of such work was told to adopt the 

 rate he liked best. As the following table (Table VI.) shows, the 

 rhythm of work was practically identical for all loads. This occurred 

 under all conditions, provided the working spells were not of too lorlg 

 duration. If the work were continued over a long period the rhythm 

 tended to alter, to increase in speed, and if the subject became really 

 tired, periods of rapid movement alternated with periods of slow 

 movement. 



