384 



NA TURE 



{August 1 8, 1887 



again. The speaker has made experiments with tuning-forks, 

 recording the vibrations of the arms by means of brushes writing 

 on a rotating drum ; in another series of experiments, which are 

 not yet concluded, he has photographed the vibrations at equal 

 intervals of time. The result of his work is that the vibrations 

 diminish in geometrical progression, thus according with theory. 

 — Dr. Wertheim gave an account of his experiments to deter- 

 mine the number of visual units in the central portions of the 

 retina. In continuation of the experiments of Dr. Claude du 

 Bois-Reymond, who has determined the number of visual units 

 in the fovea centralis and found them equal in number to the 

 cones, Dr. Wertheim, employing the same method, has deter- 

 mined the number of visual units to a distance of 2'5 millimetres 

 from the centre. A sheet of tinfoil pierced with uniform holes was 

 illuminated from behind, and then the distances were measured 

 at which the holes began to be just visible as separate objects, 

 as their image was made to fall on parts of the retina successively 

 further and further towards the periphery. After having found 

 in the fovea centralis the same number of visual units as had Dr. 

 du Dois-Reymond, he then observed that their number decreases 

 rapidly towards the periphery up to a distance of i "5 millimetres, 

 then remains constant for a short space, then diminishes again 

 rapidly, and then gradually as far as the limits of the retinal 

 area which he investigated. The speaker found that the first 

 rapid decrease extends as far as the limits of the macula lutea. 

 The anatomical statements respecting the limits of the yellow- 

 spot and the number of cones outside this area did not permit of 

 his drawing any conclusion, other than the above, from the 

 optical experiments. The same numbers were obtained when 

 red and green light was used. — Dr. Goldschneider has carried 

 out a series of experiments to test Leyden's theory that ataxy, 

 when not of central origin, is caused by injuries to centripetal 

 nerves. By passing strong electric currents through the first 

 phalanx of one finger he anaesthetized the second and third 

 phalanx, and then found that the movements of flexion and 

 extension of the finger no longer gave a regular curve of rise and 

 fall as traced by the tip of the finger : the movements executed 

 by the finger were irregular, sometimes going beyond and some- 

 times falling short of the desired extent. The sensation 

 of passive movement was also considerably lessened. The 

 speaker hence concluded that the ataxic movements are caused 

 by the interference with the sensations arising from passive 

 movements of the limbs. He added to this an hypothesis as to 

 the nature of ataxy and the seat of the muscular sense in the 

 limbs. 



July 27. — Prof. Munk, President, in the chair. — Dr. Sand- 

 mann spoke on respiratory reflexes originating in the nasal 

 mucous membrane. In order to study the possible connexion 

 between asthma and diseases of the nose, which has been 

 so often supposed to exist, the speaker has made experiments 

 on the respiration in rabbits and cats whose nasal openings 

 had been completely occluded. In addition to confirming 

 the phenomena which had been already described by earlier 

 observers, he found that the changes in volume of the 

 thorax were the same as in normal animals, whereas the intra- 

 thoracic pressure was considerably increased when breathing 

 was carried on entirely by the mouth ; similarly the respiratory 

 undulations of the blood-pressure tracing were increased in 

 amplitude. He next investigated more closely the respiratory 

 reflexes which originate in the nasal mucous membrane ; of 

 these three are known — namely, inhibition of respiration, sneez- 

 ing, and coughing, as a result of stimulation of the nose. Inhi- 

 bition of respiration was observed to occur, according to the 

 strength of the stimulation, either in the phase of expiration, or 

 of inspiration, or merely as a more pronounced expiration. 

 Sneezing was brought about by tickling the nasal mucous mem- 

 brane, and was found to consist of a deep inspiration with 

 simultaneous closing up of the pharynx and mouth by the appli- 

 cation of the tongue to the palate, followed by an explosive 

 expiration. When the stimulation is slight, only the deep 

 inspiration is produced ; if the stimulation is strong, the deep 

 inspiration is followed by a somewhat lengthy inhibition of the 

 same, which is frequently accompanied by slight expiratory 

 movements ; when the stimulation is of moderate strength an 

 ordinary sneeze is the result. After section of the phrenic 

 nerves the deep inspirations were no longer observed. Dr. 

 Sandmann, by section and removal of the mucous membrane in 

 rabbits, has further examined the various regional areas of the 

 same, and found that sneezing can only be produced by tickling 

 a limited area of the mucous membrane. On the rabbit this 



area is found in the entrance to the nose on the anterior surface 

 of the lowest nasal muscle ; but in addition to this place, the 

 same reflexes may be produced by stimulation of the front part 

 of the septum and roof of the nasal cavity. Sneezing cannot be 

 produced by stimulation of any other portion of the nasal mucous 

 membrane. In man the region of the posterior nasal openings 

 is also connected with the reflexes involved in sneezing in addi- 

 tion to the regions mentioned above. An anatomical investi- 

 gation of the areas whose stimulation leads to sneezing showed 

 that they are supplied entirely by the ethmoid nerve. Stimula- 

 tion of this nerve in the orbit was followed regularly by sneezing, 

 which could therefore be produced to a certainty by stimulating 

 the trunk of the nerve. The third kind of respiratory reflex — 

 namely, coughing as a result of nasal stimulation — could not be 

 experimentally produced in the cats and rabbits used in these 

 experiments. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



The Distribution of Rain over the British Isles, i8^6 : G. J. Symons 

 (Stanford). — First Lessons in Science : Dr. J. W. Colenso (Ridgway). — A 

 Treatise on the Principle of Sufficient Reason : Mrs. P. F. Fitzgerald 

 (Laurie). — Prolegomeni di Filosofia Elementare, Terza Edizione (Torino). 

 — Bulletin de I'Academie Royale des Sciences de Belgique, No. 6, 1887 

 (Rruxelles). — Journal of the Royal Microscopical Society, August (Williams 

 and Norgate). — ^Bulletin of the California Academy of Sciences, vol. ii. 

 No. 6. — Boletin de la Academia Nacional de Ciencias en Cordoba, Junio 

 1886 (Buenos Aires). — Journal of the Anthropological Institute, May and 

 August 1887 (Triibner). 



CONTENTS. PAGE 



The Physiology of Plants 361 



A Dictionary of Philosophy 362 



Our Book Shelf :— 



Mackenzie : "Hay Fever and Paroxysmal Sneezing" 363 

 Cohen : " The Owens College Course of Practical 



Organic Chemistry " 363 



" My Microscope " 364 



Letters to the Editor : — 



Sun and Fire Symbolism. — Mrs. J. C. Murray- 



Aynsley. {Illustrated) 364 



Bishop's Ring. — The Sky-coloured Clouds. — T. W. 



Backhouse 365 



The Electricity of the Contact of Gases with Liquids. 



—J. Enright 365 



Newton's Laws of Motion — W 366 



On the Constant P in Observations of Terrestrial 



Magnetism. — Wm. Harkness 366 



The Stature of the Human Race. — Wm. F, Stanley 366 

 A Spider allowing for the Force of Gravity. — Major 



C. B. Lyster 366 



The Lunar Eclipse of August 3. — H. H, {Illustrated ) 367 

 Botany of San Domingo. By W, T. Thiselton 



Dyer, C.M.G., F.R.S. ; Baron Eggers 367 



Constitutional Formulae and the Progress of Organic 



Chemistry 368 



The Yale College Measurement of the Pleiades. 



By A. M. Clerke 37a 



Notes 37J 



Our Astronomical Column : — 



New Variable of the Algol Type • . . . 37 



Astronomical Phenomena for the Week 1887 



August 21-27 371 



Geographical Notes 371 



The British Association 37I 



The Japan Earthquake of January 15, 1887. By 



Prof. S. Sekiya 37I 



Minerals at the American Exhibition 381 



The Folk-Lore of Ceylon Birds 38| 



University and Educational Intelligence 38a 



Societies and Academies 381 



Books, Pamphlets, and Serials Received 384 



A 



