Ivincent-cameron-armes] MUSIC AND BLOOD-PRESSURE 257 



different in each case. Lest this statement should be misunderstood, 

 it will be well to explain that according to our measurements an inter- 

 esting composition suitable for and played upon a piano will produce 

 an effect upon a musical person comparable with that produced by an 

 orchestral symphony rendered by a full orchestra. This, we take it, is an 

 indication that the effect upon the blood-pressure is a measure of the 

 aesthetic emotional effect, and not the effect of volume of sound as such. 



With regard to moderately musical and unmusical people, the 

 principal difficulty is to find musical compositions which to them will 

 be of sufficient interest to produce any effect. It is clear at any rate 

 that the vast majority of compositions which will produce emotional 

 effects upon musical people would produce much less effect on indi- 

 viduals of the other two classes. We have not experimented very fully 

 upon this point, but it seems likely that in the vast majority of such 

 people, comparable results might be obtained by the performance of 

 more elementary compositions, that is to say, definite march, dance, 

 and, generally, popular music. This introduces at once the idea of 

 association as a factor in the emotional effect. We consider this 

 factor of importance, both with unmusical persons, and with musical 

 persons hearing music well known to them, but it is difficult to estimate 

 the total bearing of this factor, and we do not propose to discuss it 

 further at this stage. 



It is possible, though we have so far not investigated the point, 

 that there is an important relationship, other things being equal, be- 

 tween the reaction time, and the impressionability to music. 



It seems to us important that investigation upon the physiological 

 effects of music should be to a very considerable extent confined to the 

 effects of instrumental music, since it is obvious that the influence of 

 words may introduce quite new factors. So far as possible, too, a 

 distinction ought to be made between the effects of tone-stimuli and 

 rhythmical stimuli. Speaking generally the effects of rhythm as 

 such are more marked in proportion to other effects in the less musical 

 groups of people. 



As for the precise action of musical stimuli upon the blood- 

 pressure, there are several possibilities: 



(1) Afferent impulses may be conveyed from the organ of hearing 

 to the nerve centres, and thence along efferent fibres to the heart, 

 affecting its force and frequency. 



(2) Afferent impulses may be conveyed from the orgsn of hearing 

 to the nerve centres, and thence along efferent fibres to the vaso- 

 motor nerves of the blood-vessels, causing vaso-constriction or dil- 

 atation in different areas, and thus affecting the blood-pressure. In 

 this case the effects would be vaso-motor reflexes. 



Sec. IV, 1914—23 



