504 



NATURE 



[March 29, 1894 



Gamble, and Mr. Hick from Owens College, Mr. W. I. 

 Beaumont, and Mr. E. T. Browne. The steam trawler Lady 

 Loch was chartered for two days, and the weather was perfect 

 for work at sea. On the first day, the sea-bottom to the north 

 cf Port Erin, from Fleshwick to Contrary Head at Peel, was 

 explored at twelve stations ranging from quarter of a mile to 

 four miles from the coast, and from depths of ten to twenty 

 fathoms. On the second day the steamer coasted along the 

 west side of Calf Island and about four miles further to the 

 west, drcdgingat nine stations from one to four miles from land, 

 and at depths of nineteen to twenty-five fathoms. Two series 

 of samples of the bottom deposits brought up in the dredge 

 were preserved, the one set for more detailed examination in 

 the laboratory, the other for transmission to the Jermyn Street 

 Museum, where the Director-General of the Survey is forming 

 a series illustrating the submarine deposits of our coasts. 

 Besides the more ordinary gravels, sands, and muds, several 

 peculiar deposits occurred, one of which was almost entirely 

 composed of the shells of Pectuncuhis glycimeris, while another, 

 which looked like a coarse sand, was seen to be formed of the 

 broken spines of Spataiigus and other Echinoderms. In some 

 places the bottom for considerable distances is covered with 

 Alelohesia and Lithothatnninm. 



The greater part of the material obtained has still to be 

 examined in detail, and will be treated of in future reports 

 of the Liverpool Marine Biological Committee. Among 

 the more noticeable forms obtained were : — The massive 

 state of Cliona celata, Sarcodiciyon catenata, the Echinoderms 

 Antedon rosacetis, Palmipes membranaceus, Luidea savignyi, 

 Stichaster roseus, Echinocardium flavesceus, Cucumaria 

 /lyndmani, Thyone fusus, and T. raphanus, Cellaria Jistnlosa, 

 Scalpellum, Tellina crassa, and the Ascidians Polycarpa comata, 

 £tjgy>-a glutitians, Ascidia plebeia, Cynthia morus, and a 

 Alicrocosiiius which seems an unknown form. Mr. Thompson 

 and Mr. Browne worked townets both on the surface and also 

 at the bottom attached to the dredge. Most of the crabs and 

 other higher Crustacea were found to be spawning, and some of 

 the Nudibranchs are spawning in the tanks at the Biological 

 Station. A common anemone a few weeks ago produced about 

 fifty young, which have now from twelve to sixteen tentacles. 



Several of the dredging party are staying on to work at the 

 Biological Station during a part or the whole of April, and 

 another dredging expedition will be arranged by the committee 

 at Whitsuntide. W. A. Herdman. 



University College, Liverpool, March 26. 



THE SCOPE OF PSYCHO-PHYSIOLOGY. 



T TNDER the title of psycho-physiology may be com- 

 ^ prised those investigations in psychology which have 

 explicit or tacit reference to the concomitant physiological 

 processes, and which are characterised by the applica- 

 tion of the experimental method. The boundaries of the 

 subject are somewhat ill-defined, since it shades off into 

 physiology on the one hand, and into introspective 

 psychology on the other. I shall endeavour m this 

 article to indicate the scope of such experimental 

 investigations. 



A chick, not many hours old, will peck with fair but 

 not complete accuracy at any small object which catches 

 its eye. Here we have a reflex and responsive action. 

 A stimulus is received in a sense-organ ; an impulse is 

 carried centripetally along ingoing or afferent nerve- 

 fibres ; certain nerve-centres are thrown into activity ; 

 and an outgoing impulse is carried by efferent nerve- 

 fibres to muscles which are thus thrown into co-ordinated 

 activity. It is probable that, on the /irst occurrence of 

 such an action, it is purely automatic and is performed 

 in virtue of the possession, by the chick, of an inherited 

 organic mechanism. It is accompanied by, but not 

 guided by, consciousness. Such guidance, however, 

 soon becomes evident. Throw to a chick two or three 

 days old half a dozen caterpillars, some of them common 

 "loopers," others yellow and black "cinnabars." In 

 the absence of previous experience they will be equally 

 seized. But the loopers will be swallowed, while the 

 cinnabars will be dropped. Repeat the experiment 

 NO. 1274, VOL. 49] 



next day. The loopers will be gobbled up at once. 

 The cinnabars will remain almost, if not quite, untouched. 

 An association has been formed between the sight and 

 taste in the two cases. Consciousness is no longer 

 merely an accompaniment of the action. It controls ; 

 enforcing the action in one case, inhibiting or restraining 

 it in the other. It is probable that in the higher parts of 

 the brain there are special centres, the physiological 

 functioning of which is associated with this conscious 

 control. Such activities of the chick, first those which 

 are merely responsive and automatic, secondly those 

 which are under conscious control, exemplify a wide 

 range of activities both in animals and man. 



Let us note the scope of the experimental work that 

 they suggest. First, there is the nature and range of 

 stimulation of the nerve-endings in the sense-organ. 

 Secondly, there is the nature and rate of transmission of 

 the impulses along the nerve-fibres afferent and efferent. 

 Thirdly, there are the nature and localisation of the 

 activities of the automatic centres, and the time occupied 

 by their peculiar functioning. Fourthly, there is the 

 physiological and psychological investigation of the 

 nature and mode of origin of the consciousness which 

 accompanies the movements of parts of the body during: 

 response. Fifthly, there are the conditions, psycho- 

 logical and physiological, of association. And sixthly, 

 there is the mode of application of the control, and the 

 localisation of specialised control centres, together with 

 the estimation of the time-element in control. 



All of these have been made the subject of carefut 

 and systematic inquiry by the method of experiment. In 

 all cases such experimental investigation has led, if not 

 to brilliant positive results, at all events to salutary 

 acknowledgment of ignorance. Difficulties of interpre- 

 tation abound. Nowhere are these difficulties greater 

 than in the investigation of the physiology and psycho- 

 logy of colour-vision. Take a dozen individuals, and get 

 them successively to indicate by means of the cross.fibres 

 of the spectroscope how far they can see along the spec- 

 trum, first in the direction of the extreme red, then in 

 the direction of the extreme violet. You will find marked 

 differences. Perhaps one will show a quite unusual 

 amount of variation, and you will probably find by other 

 tests that he is colour-blind. Is this variation in the 

 retina or in the visual centre of the brain.? It is well 

 known that the psycho-physiology of vision is still a matter 

 under discussion. One of the difficulties seems to arise 

 from the fact that what is physiologically complex is 

 psychologically simple. Purple gives a simple psycho- 

 logical sensation ; but it is due to a combination of 

 physiological impulses, the coalescence or synthesis of 

 which is, so to speak, below the threshold of consciousness. 

 One cannot, or I cannot, psychologically analyse purple 

 into its constituents, as one can analyse a musical chord. 

 There is still a wide field for research in the psycho- 

 physiology of sensation. 



An important line of investigation, which has now been 

 followed up for many years, deals, not with differences of 

 kind or of quality in sensation, but with variations in 

 intensity. Given a stimulus which excites sensation ; 

 now diminish it, on the one hand, until it ceases to e.xcite 

 sensation, and increase it, on the other hand, until it 

 reaches a maximum of sensation. Then formulate the 

 law which shall express the relation which increase of 

 stimulation bears to the increase of sensation. The 

 results of Weber's researches went to show that we must 

 look not to the absolute, but to the relative increments 

 of stimulus ; and Fechner, extending and generalising 

 Weber's results, formulated the law of the relations 

 thus : — When the stimuli increase in geometrical pro- 

 gression, the sensations increase in arithmetical pro- 

 gression, or the sensation is proportional to the logarithm 

 of its stimulus. Concerning this law, the exactitude and 

 range of its applicability, and its philosophical raison 



