20 4 



NATURE 



[Deo i er 5, 1918 



When Sii i nomas \\ i ightson stati - thai the 



thi or) " i- that Mi' I'. 1 -1I.11 ni'! ... , con- 



sist «'l" si para i strings, hi forgel .'..' th is not 

 an essential part o) the resonanci theory. Helmholtz 

 his calculations on the assumption thai the 

 membrane is homogeneous, but has a greater ti 

 lati 1 all) than longitudinal!} . 



Prof. Keith (Nature, Octobej ji) ha pointed out 

 that the work of Keith Lucas and Adrian on thi 

 " all-or-nothing " impulsi n as 



done on motor nerves only. 1 am obliged to him 

 for doing so, and apologise foi omitting to mention 

 the fact. At the same time, we know oi no such 



differences in thi pi i s ol motor and sensor) 



nerves as I a fundamental contrast of the 



kind requir d. ["here seems no inherent difficult) in 

 the performance of similar experiments on sensor) 

 fibres, using the reflex as an indicator. Perhaps 

 Dr. Adrian, win n freed from his military duties, 

 may find it possible to undertake the work. I he 

 results would be of great value. 



1 admit that the title of Sir Thomas Wrighl 

 book implies that the internal ear has analytical func- 

 tions, but it is not easy to see what these are on his 

 theory. In fact, Prof. Keith states on p. 159 of the 

 book that the relegation of the powers of analysis to 

 the cerebral cortex is the hypothesis advanced b) Sir 

 Thomas Wrightson. 



With regard to the necessary function of all struc- 

 tures found in an organism, I think Prof. Keith must 

 have misunderstood my winds; for he would scarcely 

 claim a functional importance for the details of such 

 structures as the splint-bones of the modern horse. 

 It i- in I"- n 'in inhered that Helmholtz did not profess 

 to account for the whole of the mechanism of the 

 internal ear. lie would no doubt have been the first 

 to recognise the necessity for modifications and addi- 

 tions to his theory. When we find a particular mode 

 of effecting a given object in living organisms, it by- 

 no means follows that this is the simplest or besl 

 conceivable. Structures already present, of ancestral 

 origin, are taken into use. 



As Lord Rayleigh points out, the crux of the 

 matter is the applicability of Midler's law. The parallel 

 between sound and light is not so much that between 

 the perception of pitch and colour as the percept ion 

 of the elements of an image on the retina, each of 

 which must be transmitted by its own special 

 nerve-fibre. This circumstance, together with Lord 

 Rayleigh's difficulty of admitting the capacity of nerves 

 to transmit 10,000 vibrations per second and that of 

 the "all-or-nothing" property of motor nerves, shows 

 that physical and anatomical considerations alones. 

 cannot decide the question, which is, in the end, one 

 of physii 



It does not seem impossible that investigations with 

 the Einthoven galvanometer might throw light on thi 

 form of the impulses in the auditory nerve. Even 

 if the wave-form were beyond the capacity of the 

 instrument, the number of impulses per second in 

 relation of the pitch of the note and 



the nil" riod of the nerve might be deter- 



mined. 



Dr. Perrett's difficulties (Nature, November 7) 

 relate to thi i stenl of spread of a resonant vibration 

 and to thi perfection oi damping. It seem- to 

 to be unreasonable to hind Helmholtz to 1 

 numerical data, considering the enormous difficulties 



involved in thi d nation of the physical constants 



of the auditory apparatus. Nor are the numi 

 values used by Helrahol for approximate calcula- 

 tions in be regarded as the 1. stone of his theory." 



At an) rati . the amplitude oi b 



decn ases ver) stei pi) as the maximal 

 point is departed from, and the fact that below a 

 certain intensify of stimulus a nerve-fibre is not excited 

 at all suggests the possibility that the amplitude of 

 vibration may be sufficiently great to bi only 



in tmmi liate proximity to the maximi 



The sudden cessation of the peri eption ol 

 when iis source ceases, as required by phonetics, is, 

 as Dr. Pen el I is aw are, a question of thi pi 

 of damping. I fail to sei wh) we an necess; 

 limited to any particular value of the reduction in a 

 given time by the cochlea) apparatus, be this valui 

 one-tenth or otherwise. ["hi fact that a resonant 

 vibration may be practically "dead-beat" was made 



1 li ai in me in a recent 1 peri al an orchi 



concert. The floor-board on which one of nv, fei 

 lifted resounded by vibration to a particular i 

 especially to the powerful one of the tromboni 

 or drum. But the interest la) in the fact that this 

 vibration ceased instantaneously as soon as the ex- 

 citing note ceased, doubtless owing to the effective 

 damping bv the benches and the feel of the audience. 



There is one phenomenon which has not been 

 referred to hitherto in the present discussion : tin 

 disputed question as to whether the different com- 

 pound wave-forms produced by different phase illa- 

 tions of the same component tones affect the qualit) 

 of the sound heard. Helmholtz stand that they did 

 not, but oilier observers have stated the contrary. Sir 

 Thomas Wrightson 's theory would be able to account 

 for a difference, but the resonance theory would not. 

 Unfortunately, the statements are very contradictory, 

 and it does not appear that the experiments made by 

 those who found phase relation to be effective were 

 such as to exclude differences other than those of 

 phase in the complex tones produced. 



The desirability of a decision of the question at 

 issue, if possible, may serve as excuse for a further 

 letter on my part, for the length of which I beg to 

 .gise. W. M. Bayliss. 



University College, London. 



International Prize for Scientific Work. 



I have recently received from one of the secretaries 

 of th. Royal Academy of Turin a printed Latin notice 

 of the conditions prescribed for the next award of an 

 international prize of the net value of 9000 Italian lire 

 founded by Cesare Alessandro Brussa.M.D. Theprize 

 is to !"■ awarded to the vir doctus who has produced 

 that which, in the judgment of thi- academy, is thi 

 most important and most useful invention or the most 

 important work during the four years between 

 January 1, 1915, and January 1, 19m, in any of the 

 following departments of study : — Physics, or other 

 branches of experimental science; natural h 

 mathematics (pure or applied); chemistry; physiology; 

 pathology; geology; history; geography, or statistics. 



II. . who are proposing to compete for the prize 

 are requested to send their inventions or their works 

 to one of the secretaries of the academy (Prof. C. F. 

 Parona, secretary for physical, mathematical, or 

 natural sciences, or Prof. E. Stampini, secretary for 

 moral, historical, or philological sciences) before 

 January t, i.ho. Any works sent must be printed. 

 but will not be n turned (works in manuscript or type- 

 written an inadmissible). The academy may also 

 award the prize to one who In- not submitted any 

 work. The prize is open do> uslibet nationis 



but Italian members pi thi ... idem; an not eligible. 

 ■ idge. J. E. Sand 



NO. 2562, VOL. I02] 



