No. I.] THE VERTEBRATE EAR. 301 



strike upon the tympanum as two distinct impacts so far as 

 their fundamental tones are concerned, but as single condensa- 

 tions and rarefactions or pressures and relaxations as the motion 

 is transferred mechanically from the air to the ear drum. This 

 main (combinational) pressure and relaxation is accompanied by 

 minor ones of different pitches and varying, but in all cases less, 

 intensities. When these are further transmitted and produce 

 the sensations of tone, how does the ear separate the subdivis- 

 ional tones and harmonics of the piano note from those of the 

 violin note.? As Koenig has clearly shown, "if the ear could 

 always separate the pure harmonic or absolutely inJiarmonic par- 

 tials from their fundamental tone, or if it always heard pure 

 harmonics as an indistinguishable part of the unity of the timbre 

 of a fundamental tone, then we might draw a hard and fast line 

 between mere mixtures of sound and timbre." Such, however, 

 is not the case. We cannot perceive these minute distinctions 

 without special care and physical aid ; for often the ear cannot 

 detect the inharmonious partials when present, and does, on the 

 other hand, often separate out the harmonious partials (Koenig), 

 and, besides, in the last analysis, timbre is simply due to a rapid 

 accented sequence of tones, and not to a mixing of simple 

 tones. 



Here, as elsewhere, however, much depends upon the sensi- 

 tiveness and delicacy of the ear and central association appa- 

 ratus. The passage of sound through the ear of one person 

 is much the same as the passage of light through a plate of 

 glass, while in the ear of another (or perhaps the brain) the 

 same apparently simple unitary sound would be drawn out in a 

 harmonious chord much as white light is separated into its 

 spectrum of component colors by passing through a prism. 

 Koenig concludes from his experiments that melody is associa- 

 tive rather than physical. 



That the appreciation of sound is a mental act has long been 

 recognized, and Foster cautions us to bear it in mind. This 

 being true, and allowing for the moment that there is an analy- 

 sis of the compound sound wave by the fibres of the basilar 

 membrane, or any other auditory structure, Foster does not 

 make clear how this can be so, while at the same time, as he says 

 {loc. cit. p. 1214), "We do not receive a distinct series of spe- 

 cific auditory impulses resulting in a specific sensation for every 



