5 6 ° 



NA TURE 



[October 2 1, 1922 



demands, be applied so that the load on the fibres is 

 small near the base, but large near the apex. 



A great difficulty in supposing that the basilar 

 membrane represents a system of resonating strings 

 is the fact that it is immersed in fluid. It is precisely 

 this point which Dr. George Wilkinson, in a paper 

 read before the Section of Physiology of the British 

 Association at the recent Hull meeting, conceives to 

 be, not a difficulty, but the key of the whole problem. 

 He suggests that the differentiation of the fibres as 

 to mass, or the " loading " of the fibres, is brought 

 about by the fluid in the canals. When the fibres 

 at any point of the membrane vibrate in response to 

 an impulse from the middle ear, they will be loaded 

 by tin- weight of a column of fluid proportional to 

 the distance of the vibrating point from the fenestra 

 rotunda, which is the window between the cochlea 

 and the middle ear. The column of fluid between 

 the window and the vibrating point will be least in 

 the case of a point on the membrane near the base 

 of the cochlea, and greatest in the case of a point 

 near the apex. 



So much for Dr. Wilkinson's theoretical conception. 

 He has provided a convincing proof of his views in 

 the shape of two very ingenious models. The first 

 is a brass box divided horizontally into two like 

 the cochlea unwound from its spiral. The partition 

 which represents the basilar membrane consists of a 

 series of parallel wires of phosphor-bronze soldered 

 firmly in position, and covered with formalised 

 gelatin. On this basilar membrane is scattered blue 

 enamel powder. There is a fenestra rotunda and 

 ovalis at one end of the box, respectively above and 

 below the basilar membrane, the windows being 

 formed in each case by a rubber disc. The box is 

 filled with water and is completely closed. In his 

 first model, Dr. Wilkinson has kept all his phosphor- 

 bronze wires at the same tension and of the same 



length. Yet he finds that when he applies a vibrating 

 tuning-fork to the rubber membrane, or fenestra 

 rotunda, the powder on the basilar membrane takes 

 up a definite position which varies with tuning- 

 forks of different rates of vibration. Thus a 200 

 D.V. fork produces a localised resonant response at 

 a distance 3-3 cm. from the proximal end of the scale, 

 while a 400 D.V. fork produces such a response at a 

 distance of o-q cm. If one makes use of the formula 

 for vibrating strings and supposes that the differentia- 

 tion in resonance is due to the different loading of 

 the wires by the fluid according to the above 

 hypothesis, then the point of resonance to the lower 

 tone should be 4 times the distance from the windows 

 compared with that for the upper tone. Actually 

 we see that it is not 4 times, but is 3-3/0-9 = 3-6 times. 

 A very striking agreement ! 



Here then is proof of Dr. Wilkinson's contention 

 that a system of transverse fibres, immersed in a 

 fluid as it is in the cochlea, is already, by reason of 

 the position of the fenestra, differentiated for 

 resonance in regard to the effective mass of the 

 fibres. 



In his second model, which is larger, he has carried 

 out a differentiation of his phosphor-bronze wires in 

 respect of tension and length. The differentiation 

 of tension is effected by attaching weights of different 

 sizes to the ends of the individual wires ; while the 

 lighter weights are attached to the longer fibres near 

 the " apex," the heavier weights are attached to the 

 shorter fibres near the base. In this way he has 

 attained a model which gives a localised resonant 

 response over a range exceeding four octaves. 



One may say in conclusion that Dr. Wilkinson 

 has made a very considerable contribution to our 

 knowledge of the mechanism of hearing, and has 

 presented the first clear conception of how the 

 cochlea can work. 



British Association Research Committees. 



"O ESEARCH committees to deal with the following 

 -I »- subjects were appointed by the General Com- 

 mittee at the recent meeting of the British Association 

 at Hull. The names given are those of the chairmen 

 and secretaries of the committees. 



Section A (Mathematics and Physics). — Seismo- 

 logical investigations : Prof. H. H. Turner, Mr. J. J. 

 Shaw. To assist work on the tides : Prof. H. Lamb, 

 Dr. A. T. Doodson. Annual tables of constants and 

 numerical data, chemical, physical, and technological : 

 Sir Ernest Rutherford, Prof. A. W. Porter. Calcula- 

 tion of mathematical tables : Prof. J. W. Nicholson, 

 Dr. J. R. Airey. Determination of gravity at sea : 

 Prof. A. E. H. Love, Prof. W. G. Driffield. Investiga- 

 tion of the upper atmosphere : Sir Napier Shaw, 

 Mr. C. J. P. Cave. To aid the work of establishing 

 a solar observatory in Australia : Prof. H. H. Turner, 

 Prof. W. G. Duffield. 



Section B (Chemistry). — Colloid chemistry and 

 its industrial applications : Prof. F. G. Donnan, Dr. 

 W. Clayton. Absorption spectra and chemical con- 

 stitution of organic compounds : Prof. I. M. Heilbron, 

 Prof. E. C. C. Baly. 



Section C (Geology). — The Old Red Sandstone 

 rocks of Kiltorcan, Ireland : Prof. Grenville Cole, 

 Prof. T. Johnson. To excavate critical sections in 

 the palaeozoic rocks of England and Wales : Prof. 

 W. W. Watts, Prof. W. G. Fearnsides. The collection, 

 preservation, and systematic registration of photo- 

 graphs of geological interest : Prof. E. J. Garwood, 

 Prof. S. H. Reynolds. To consider the preparation 

 of a list of characteristic fossils : Prof. P. F. Kendall, 

 Mr. H. C. Versey. To investigate the flora of lower 



NO. 2764, VOL. I IO] 



carboniferous times as exemplified at a newly dis- 

 covered locality at Gullane, Haddingtonshire : Dr. 

 R. Kidston, Prof. W. T. Gordon. To investigate 

 the stratigraphical sequence and palaeontology of the 

 Old Red Sandstone of the Bristol district : Mr. H. 

 Bolton, Mr. F. S. Wallis. 



Section D (Zoology). — To aid competent investi- 

 gators selected by the committee to carry on definite 

 pieces of work at the Zoological Station at Naples : 

 Prof. E. S. Goodrich, Prof. J. H. Ashworth. To 

 summon meetings in London or elsewhere for the 

 consideration of matters affecting the interests of 

 zoology, and to obtain by correspondence the opinion 

 of zoologists on matters of a similar kind, with power 

 to raise by subscription from each zoologist a sum of 

 money for defraying current expenses of the organisa- 

 tion : Prof. S. J. Hickson, Dr. \V. M. Tattersall. 

 Zoological bibliography and publication : Prof. E. B. 

 Poulton, Dr. F. A. Bather. Parthenogenesis : Prof. 

 A. Meek, Mr. A. D. Peacock. To nominate competent 

 naturalists to perform definite pieces of work at the 

 Marine Laboratory, Plymouth : Prof. A. Dendy 

 (Chairman and Secretary). Experiments in inherit- 

 ance in silkworms : Prof. W. Bateson, Mrs. Merritt 

 Hawkes. Experiments in inheritance of colour in 

 Lcpidoptera : Prof. W. Bateson (Chairman and 

 Secretary). 



Section E (Geography). — To consider the ad- 

 visability of making a provisional population map 

 of the British Isles, and to make recommendations 

 as to the method of construction and reproduction : 

 Mr. H. O. Beckit, Mr. F. Debenham. 



Sections E, L (Geography, Education). — To 



