200 



NA TURE 



[August 12, 1909 



tude, and it ma_v be found that the slow variation of thu 

 z component, especially in phase, is not unconnected with 

 the sixty, or seventy-hvc, year period of the annual term 

 which was announced by Dr. Chandler. 



Reports of Observatories. — Mr. Hough's report of the 

 work done at the Cape Observatory during the year igoS 

 cannot be summarised effectively in a brief note, but one 

 or two points may be especially recorded. The Victoria 

 telescope was in use on 165 nights to secure 601 stellar 

 spectra for line-of-sight determinations ; the solar parallax 

 programme having been completed in May, the spectro- 

 graph was dismounted, repaired, and adjusted, and is now 

 employed in the determination of the radial velocities of 

 365 stars between declination 30° N. and the south pole. 

 The value obtained for the parallax was 8-Soo" ±0006". 

 The astrographic telescope was employed in taking proper- 

 motion and parallax plates of some of Prof. Kapteyn's 

 " selected areas. " 



In the report of the Paris Observatory for 1908 M. 

 Baillaud outlines the re-organised programme of the 

 observatory work. Among other things, we note that the 

 small equatorial coudi is to be employed, by M. Hamy, for 

 the study of sun-spot spectra. 



Solar Research. — In the August number of the 

 Observatory Mr. A. A. Buss discusses, at some length, the 

 possible purport of the results obtained in recent solar 

 research, dealing principally with appearance of the D, 

 line of helium. In concluding, he states that he has, on 

 a number of occasions in recent years, seen immense 

 " dark " hydrogen clouds projected on the dark background 

 of the sun's surroundings; this phenomenon he attributes 

 to the projection of the clouds against the slight luminosity 

 of the sun's hydrogen corona. 



A Brilliant Meteor. — -Observing at Marseilles on 

 June 26, M. Borrelly saw a splendid meteor, which 

 appeared at i4h. o'm. 56s. (Marseilles M.T.), and 

 illuminated the whole of the sky for some three seconds. 

 The light was extraordinary, and the meteor travelled from 

 Pegasus to the Dolphin, above € Pegasi, in a N.E. 

 direction (Astronomische Nachrichten, No. 4339). 



PHYSIOLOGY AT THE BRITISH MEDICAL 

 ASSOCIATION. 



' I "HE chief points of general scientific interest in the 

 proceedings of the British Medical .Association at 

 Belfast are to be found in the communications read in 

 the sections of anatomy and physiology, bacteriology and 

 pathology, on July 28-30. The following account is prac- 

 tically limited to a brief summary of Prof. Sherrington's 

 presidential address to the section of anatomy and physio- 

 logy, entitled " The Deep Aliferents — their Distribution 

 and Function." 



In contrast with our considerable knowledge of the 

 surface afferents, our knowledge of the deep afferents is 

 relatively slight. The deep afferent system may be sub- 

 divided into a visceral and a muscular portion, using the 

 latter term in a somewhat wide sense. 



From one point of view the visceral portion may be 

 regarded as superficial with reference to the lining mem- 

 brane of the alimentary canal and respiratory passages, 

 but practically this fact may be neglected. The conscious- 

 ness of the body is normally almost entirely confined to 

 the e.xternal surface. When we take food, it normally 

 disappears from our ken after its passage through the 

 fauces, and consequently if we were guided only by our 

 own consciousness we might doubt the likelihood of the 

 existence of visceral afferents associated with sensation. 

 Vet numerous examples of dim visceral sensations, 

 •especially gastric ones, might be adduced. For example, 

 after drinking hot fluids a characteristic gastric sensation 

 IS produced. Under pathological conditions numerous 

 visceral sensations may be obtained. The explanation and 

 localisation of the latter form a fruitful field, in the in- 

 vestigation of which physiologists. anatomists, and 

 clinicians might usefully combine. Further, it has long 

 teen recognised that afferent nerves are not necessarily 

 associated with sensation. Numerous examples of this 

 Trict will be given in the course of this account. 



NO. 2076, VOL. 81] 



The mouth and nasal cavities form an intermediate field 

 between the e.xternal surface of the body supplied by the 

 superficial afferents, and the remainder of ine alimentary 

 canal and the respiratory passages supplied by the deep 

 visceral afferents. In this region the nature of the effective 

 stimuli alters. Whereas mechanical and physical stimuli 

 are specially effective when applied to the external surface, 

 chemical stimuli, both gustatory and olfactory, become 

 specially effective in the intermediate zone both in the 

 direction of yielding sensations and of inducing reflexes. 



Prof. Sherrington next passed from the consideration 

 of this intermediate field to that of the deep visceral 

 afferents proper. Formerly, gastric and intestinal move- 

 ments and digestion were believed to be controlled by 

 mechanical and chemical stimuli affecting afferent visceral 

 nerves. More recently a deeper insight into the mechanism 

 controlling gastric and intestinal movements and digestion 

 has revealed a number of difficulties which militate against 

 the acceptance of the older views. For example, the 

 intestinal movements, both the simple pendular and the 

 more powerful and less frequent peristaltic movements, 

 take place in an isolated loop of intestine after section of 

 all the nerves passing to the loop. In this case there 

 cannot only be no conscious reaction, but even no true 

 reflex act. Further, the removal of the abdominal sympa- 

 thetic in the dog does not cause any obvious alteration in 

 digestion or intestinal movements. Under such conditions 

 the regulation of movements and digestion is controlled by 

 the intrinsic nerve mechanism of the alimentary canal, 

 namely, Auerbach's and Meissner's plexuses. 



A very interesting phase of recent physiology is the 

 suggestion by Bayliss and Starling of a mode of chemical 

 regulation other than that through the nervous system. 

 They have extracted from certain organs substances called 

 hormones, which are capable of exciting the activity of 

 correlated organs. One of the best known of these is 

 secretin. Bayliss and Starling showed that secretin is 

 effective after severance of nervous connections, and have 

 thus rendered doubtful Pawlow's view that the co-adjust- 

 ment of organs is mainly nervous in origin. Other ex- 

 amples of hormones are a substance extracted from the 

 cardiac end of the stomach, which acts on the pyloric end, 

 and carbon dioxide, which may be regarded as the hormone 

 affecting the bulbar respiratory centre. 



Prof. Sherrington next passed to a subject of great 

 theoretical and practical interest, namely, visceral pain. 

 This subject has long formed a field of controversy, largely 

 on account of the obvious difficulties in the way of its 

 investigation. The observations which have been made on 

 visceral pain are best dealt with in historical sequence. 



Haller, one of the earliest investigators of this subject, 

 distinguished parts which feel from those which do not 

 feel. He incjuded the viscera, tendons, and blood-vessels 

 amongst the non-feeling parts. His results were largely 

 obtained by investigation of the human subject, using 

 interrogation of the patient as the test. He also experi- 

 mented on animals. The methods of stimulation used in 

 the latter cases were extreme in character, and con- 

 sequently throw no light on the results which might be 

 obtained by the use of more normal and adequate stimuli. 

 Johannes Miiller held views diametrically opposed to those 

 of Haller. He maintained that the viscera are sensitive. 



.Amongst later observers, Head almost takes visceral 

 pain for granted, and, following Ross, develops the idea 

 of "referred pain." Lennander's papers are the most 

 recent on this subject. .As the result of experiments on 

 man, he comes to the conclusion that the abdominal and 

 thoracic viscera do not feel. The parietal peritoneum is 

 also insensitive, but the subserous layer of the peritoneum 

 is highly sensitive even under normal conditions. When 

 slightly inflamed the subserous layer becomes hyper- 

 sensitive. 



Meltzer's results are opposed to those of Lennandcr. 

 From a large series of experiments, chiefly on the dog, 

 but also on man, he comes to the conclusion that stimula- 

 tion of the liver and intestines elicits reactions that indicate 

 pain. .After a short period of exposure to the air, the 

 viscera appear to become hvpersensitive, slight stimuli 

 producing well-marked reactions. 



On considering the results obtained by these observers, 

 it is difficult to imagine that the powerful vase-motor re- 



