May 13, 1897] 



NATURE 



45 



meeting of the Society. Miss Scott attempts to show, "as a 

 matter of purely pedagogic interest," how simply and naturally 

 Cayley's theory follows from a small number ot very elementary 

 i^eometrical conceptions, without any appeal to analytical 

 •geometry. — Lines common to four linear complexes, is a 

 short note, by Dr. V. Snyder, which was read at the February 

 meeting. — The cubic resolvent of a binary quartic derived by 

 invariant definition and process, by Prof. H. S. White, was 

 read at the Chicago Conference (January i, 1897).— Dr. Isabel 

 Maddison reviews two recent works on geometry, viz. Phillip's 

 and Fisher's "Elements of Geometry," and II. D. Thompson's 

 " Elementary Solid Geometry and Mensuration," which she 

 thinks rise above the general level. Dr. Maddison also points 

 out that the map-colouring problem was discussed (before 

 Cayley and De Morgan wrote upon it) by Mcibius, in his lec- 

 tures in 1840. The problem was propounded to Mobius by 

 Prof. Weiske, and is to be found in the Berichte der Sachsischen 

 Gtsellschaft der Wissenschaften zti Leipzig, Math.-physiche 

 Classe, Bd. 37, 1885. The Note referred to is by Prof. Baltzer, 

 and its title is " Fine Erinnerung an Mobius und seinen freund 

 Weiske." — The Notes contain the mathematical courses at the 

 Lniversities of Berlin and Harvard. 



The last number oi ihe Journal of i/ie Russian Chemical and 

 Physical Society contains, in an appendix, the third instalment 

 '.f the " Record" {Vremennik) of the Russian Chief Board of 

 Measures and Weights. Most of it is given to an elaborate 

 paper, by Prof. Mendeleeft", on the "Methods of Accurate or 

 Metrological Weighings." The formula; relative to the oscilla- 

 tions of the scales' index, and to the " condition " of the scales, 

 are discussed in great detail, and new formula are given ; while 

 the discussion of some of the results has brought the Russian 

 professor to the discovery of a new property of the parabola 

 relative to the surface of a segment of it (Coviptes rendus, 1895, 

 p. 1467). — The same issue contains papers on the quantity of 

 carbon dioxide contained in the air of the Weighing Hall of the 

 Board of Measures and Weights, by A. Dobrokhotoff ; the 

 results of the verification at the Standards Department of the 

 P.oard of Trade, in 1894 and 1895, "f the Avoirdupois Pound 

 belonging to the Russian Government, and the comparison of 

 the Russian half-sashen with the Imperial standard yard, by H. 

 J. Chaney, Mendeleeff, and Blumbach (in English and Russian) ; 

 on the geographical position of the Board of Measures (chiefly 

 its exact altitude above the sea-level) ; and a note, by Prof. 

 Mendeleeff, on the agreement of the author's well-known formula 

 for the density of water at different temperatures with the last 

 measurements of the same, by M. Thiesen. 



Bolleltino delta Societa Sismolo^ica Kaliana, vol. ii., 1896, 

 N.N. 7, 8. — Influence of the different nature and sensitiveness of 

 instruments on the measure of the velocity of seismic waves, by 

 G. Agamennone.— On the geodynamic system of the world, by 

 G. Grablovitz. — Summary of the principal eruptive phenomena 

 in Sicily and the adjacent islands during the six months July- 

 December 1896, by S. Arcidiacono. — Velocity of propagation 

 of the earthquake of Ahmed (Asia Minor) of April 16, 1896 (in 

 French), byG. Agamennone. — Vesuvian notes for the year 

 by G. Mercalli.— Notices of earthquakes recorded 

 August 3 1 -September 8, 1896 



[896, 

 Italy, 

 the most important being a 

 series of records of the Iceland earthquake of September 6. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, April 8.—" Further Note on the Sensory 

 Nerved of Muscles." By C. S. Sherrington, M.A., M.D., 

 F.R.S., Holt Professor of Physiology in University College, 

 Liverpool. Received February 26. 



I was somewhat surprised when, after the sensory nature of 

 the structures originally termed muscle-spindles (Kiihne) had 

 been proved (Sherrington), I was unable to find in the eye- 

 niuscles any examples of these structures. I had expected to 

 find in those muscles, on account of the great delicacy of their 

 control and coordination, and in view of the well-known rich- 

 ness of their innervation, a field peculiarly favourable for the 

 examination and study of " spindles." 



I had noted that the intrafusal muscle-fibres, of the "red" 

 variety as they are, undergo, when the nerve-trunk of a muscle 

 has been severed, a much slower course of alteration than do 

 extra-fusal muscle fibres, i.e. I found no pronounced degenera- 



NO. 1437, VOL. 56] 



tion for even two years following section. I therefore cut 

 through «, oculomotorius at its origin, and examined the re- 

 sultant degenerations in the eye-muscles which it innervates 

 and in their individual nerve-trunks. 



In the nerve-trunks, extra-muscular and intra-muscular, the 

 Wallerian degeneration clearly demonstrated that, with the 

 exception of a few minute fibres, of variable number, derived 

 perhaps from the ciliary ganglion, all myelinate nerve-fibres in 

 all these eye-muscles degenerate. Therefore these eye-muscles 

 derive the vast majority of their myelinate nerve-fibres from n. 

 oculomotorius. The sensory innervation of these muscles is not, 

 therefore, derivable from the fifth cranial pair. In accord with 

 this, I found (o) that severance of both trigemini caused no 

 obvious impairment of the movement of the eye-balls, (;8) that 

 the combined severance of both nn. trigemini, and of both 

 optic nerves, even after section of the encephalic bulb, did not 

 severely depress the tonus of the eye-muscles. Now we know 

 that section of the sensory spinal roots belonging to muscles 

 does very severely depress the tonus of them. 



At the same time, I was struck with the long distance to 

 which many of the nerve-fibres in the.se muscles travel forward 

 towards the ocular tendons of the muscles. I was the more 

 impressed with this fact because direct examination proved that 

 the regions of the distribution of motor end-plates in these 

 muscles is almost confined to the middle portion of the fleshy 

 mass of the muscle. Further investigation of the course and 

 destination of the nerve-fibres at the tendon end of the muscle 

 revealed them (both in cat and monkey) undergoing terminal 

 subdivision, and in numerous instances passing beyond into 

 the bundles of the tendon itself. The terminations of some 

 of these nerve-fibres lie within the tendons ; many recurve 

 again towards the muscular fibres, and end just at junction 

 of muscle-fibre with tendon-bundle. The nerve-fibres in so 

 terminating frequently become thick— as I have described in 

 the case of muscle-spindles— with shortened internodes. 



My observations have included also the fourth cranial pair, 

 and with like result. Investigation of the sixth cranial pair is 

 also in progress. 



It also appears from the above that the absence of the 

 distinct Kiihne- Ruffini "spindles" from a muscle does not 

 exclude the possession by it of sensorial end-organs, and of 

 afferent nerve-fibres.. This point is not without importance, 

 because examination of various muscles has led me to the con- 

 clusion that the " spindle-organs " are absent from the following 

 muscles : — From all the orbital eye-muscles ; from the intrinsic 

 muscles of the larynx, though Pacinian corpuscles occur, as in 

 various other muscles ; from the intrinsic muscles of the tongue, 

 and from the diaphragm. It is notable that all these muscles 

 belong to that set which are innervated by nerve-fibres of rather 

 smaller calibre (Gaskell) than those supplying the skeletal 

 muscles generally ; that is to say, are innervated by the non- 

 ganglionated splanchnic efferent nerves of Gaskell. 



" On Boomerangs." By G, T. Walker, M.A., B.Sc, Fellow 

 of Trinity College, Cambridge. Communicated by Prof. J. J. 

 Thomson, F. R.S. Received March 15. 



A typical returning boomerang resembles in general outline a 

 symmetrical arc of a hyperbola, and is about 80 cm. in length 

 measured along the curve. At the centre, where the dimensions 

 of the cross section are greatest, the width is about 7 cm., and 

 the thickness i cm. 



Of the two faces, one is distinctly more rounded than the 

 other ; in addition the arms are twisted through about 4°, in the 

 .same manner as the blades of a right-handed screw propeller. 



Such an implement, if thrown with its plane vertical, will 

 describe a circular path of 40 or 50 metres in diameter, rising 

 to a height of from 7 to 12 metres, and falling to the ground 

 with its plane of rotation horizontal at a point somewhere near 

 the thrower's feet. 



The flight may be regarded as a case of steady motion, of 

 which the circumstances gradually vary. In the more compli- 

 cated, as well as the simpler, paths, observation makes it clear 

 that everything depends on the changes in direction and in- 

 clination of the plane of the boomerang, and that the character 

 of these changes is always the same ; if they can be ex- 

 plained theoretically, the peculiarities of the motion may be 

 accounted for. 



Since the effects of the different forces at work are conflict- 

 ing, it is necessary to adopt quantitative methods, even if the 

 degree of accuracy attainable is not high ; accordingly ratios 



