258 THE ROYAL SOCIETY OF CANADA 



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

 to the nerve centres, and efferent impulses pass down to the muscles 

 of respiration causing alteration in depth and frequency. This is 

 comparable with the effect upon respiration produced by stimulating 

 the central end of the sciatic nerve. In the latter case the effect is 

 very pronounced, the breathing is rapid and deep, and there is a 

 marked fall in blood-pressure, due, we believe, to direct interference 

 with the heart's action. In the case of tone-stimuli conveyed along 

 the auditory nerve the stimulus is of course of a different character, 

 and never produces the same kind of effect upon breathing, but effects 

 are produced, and these undoubtedly affect the blood-pressure. It 

 seems for example that the diminished breathing for a period, followed 

 by a deep sigh at intervals, referred to above as characteristic of at- 

 tention, will in general produce a distinct fall of pressure. The effects 

 of different kinds of breathing upon the blood-pressure have never 

 been fully investigated, and we hope to report more fully upon these 

 in a later communication. 



(4) Afferent stimuli arising from tones can only be conveyed 

 along other nerves than the auditory, in the case of very deep tones. 

 Similar reflexes to those described above might occur in this case, 

 but such could scarcely be reckoned as musical stimuli. 



Of the three causes, that affecting repiration is undoubtedly 

 largely responsible for all falls of blood-pressure correctly traceable 

 to musical stimuli, while that affecting rate of heart beat we consider 

 largely responsible for rise of blood-pressure for the following reasons: 



(a) It has been observed by Porter and others, and confirmed by 

 ourselves, that electrical stimuli of equal intensity applied to the cut 

 central end of the sciatic of the dog at different heights of blood pres- 

 sure (in different animals, or produced by bleeding) result in numeri- 

 cally equal changes in the height of blood-pressure. This is an effect 

 upon the blood-vessels. 



(b) On the contrary, in our experiments, we have observed that, 

 as far as we can judge, similar musical stimuli produce on persons of 

 the same temperament, but with different blood-pressures increases 

 or decreases of blood-pressure proportional to the height of blood- 

 pressure. This leads to the results, which we have repeatedly ob- 

 tained, that the effect in women (low blood-pressure) is numerically 

 less than in men, while in the case of one individual, observed over a 

 considerable range of normal pressure, the same result held generally. 

 This result would be produced in a closed system of fixed size, by 

 alteration of the rate of heart-beat. 



In accordance with modern physiological conceptions the emotion 

 is the result of physical changes. If this be the case, it seems reason- 



