282 AVERS. [Vol. VI. 



(Klangapparat), it seems to me he contradicts important state- 

 ments made in the preceding pages of his work. For he holds 



— as almost every one else does — that there are three deter- 

 mining physical conditions to the production of tone stimuli ; 

 viz. the pitch, or rate of vibration ; the intensity, or amplitude 

 of vibration ; and the timbre, or the complexity of vibration ; and 

 furthermore, it is the essential part of his theory that the basilar 

 membrane fibres repeat as near as may be the rate, intensity, 

 and complexity of the waves which cause any given tone sensa- 

 tion. For how could the basilar membrane otherwise analyze 

 tonal waves, and would our author have us look for another 

 apparatus to perceive the very thing that determines the selec- 

 tion of the waves in the cochlea? To say, then, that the rate 



— or the condition which determines whether a tone is a "low " 

 or a "high" one — does not immediately concern the cochlear 

 apparatus is to deny that the basilar membrane vibrates sympa- 

 thetically to tone stimuli, which contradicts the corner-stone of 

 the Helmholtz theory. 



Hensen cites J. Miiller's dictum that " Jeder Ton erweckt sein 

 besonderes Gefiihl," and says that the tonal pitch does not play 

 any immediate part in awakening this special sensation. He 

 says, further on, "Ob daher die Hohe und Tiefe des Tons eine 

 einfache Empfindung und nicht vielmehr ein complicirterer Act, 

 bei dem das Gedachtniss wesentlich mitwirkt, eine Wahrneh- 

 mung ist, erscheint noch zweifelhaft." 



In this conclusion our author begs the question ; for while 

 there is not the slightest doubt that the inadequately understood 

 cerebral operations play an important part in all auditory per- 

 ceptions, we must, while we are considering the physical basis 

 of sound, confine ourselves to this alone ; for the moment the 

 co-ordinating apparatus is introduced into the problem it be- 

 comes altogether too complex to deal with at this time ; on the 

 other hand, we may reasonably expect to get some important 

 facts by studying the effects of physical auditory stimuli from 

 the physical standpoint. 



Hensen feels compelled to seek for two distinct apparatuses 

 in the ear : one for tone perception, another for other forms of 

 sound, and the theory of the analysis of sound waves is at the 

 bottom of it all. 



