NATURE 



529 



THURSDAY, APRIL 6, 1905. 



rsycuoLOGY and physiology. 



Grnndzuge der physiologischen Psychologie. Von 

 Wilhelm Wundt. 5th edition. Vols. ii. and iii. 

 Pp. viii + 865, ix + 796 and 133; and Gesamtregister. 

 (Leipzig: Engelmann, 1902-3.) Prices 13s., 145., 

 and 3s. 



Principles of Physiological Psychology. By Willielm 

 Wundt. Translated from the fifth German edition 

 by E. B. Titchener. Pp. xvi + 347. (London : Swan 

 Sonnenschein and Co., Ltd., 1904.) Price i2S. 



WITH these two volumes Prof. Wundt concludes 

 what in all probability is the last edition of 

 this great work prepared by his own hand. The 

 single volume of the first edition of 1874 is now 

 expanded to three large volumes comprising 2168 

 pages. Founded, as it is, chiefly upon the author's 

 own researches and those of his pupils, the treatise 

 forms a splendid monument to his life-long labours 

 in a field in which he has been for long a pioneer and 

 the most prominent figure. 



The main part is an expansion and development 

 of the views expounded in earlier editions in accord- 

 ance with the data that have accumulated so rapidly 

 in recent years. For, as Wundt points out, psychology 

 has now happily achieved methods of research by 

 which any intelligent and industrious worker may 

 add something, however small, to the mass of 

 empirical data on which the future science is to be 

 built up, and in so doing has assured its place among- 

 the progressiv'e sciences. To this edition a final 

 section is added, in which the veteran thinker sets 

 forth his matured conclusions on the general 

 principles of psychology and on its relations to other 

 sciences. To the exposition of one of the most im- 

 portant of these principles this article may profitably 

 be devoted. Not many years ago most writers who 

 discussed the functions of the brain postulated what 

 they called a sensoriuni commune, a central nervous 

 organ or " centre " in which the afferent nerves of all 

 the sense-organs were supposed to come together, 

 and to the substance of which each such nerve was 

 supposed to communicate its specific mode of activity, 

 generally assumed by those writers to be some 

 peculiar form of molecular vibration. It was 

 supposed, therefore, that when two or more sensory 

 nerves of different functions are simultaneously stimu- 

 lated, this "centre" becomes the seat of a complex 

 resultant physical process, embodying the specific 

 characters of the two or more kinds of neural process. 

 And this hypothetical physical resultant was held 

 to be the imroediate correlate or excitant of the 

 complex affection of consciousness. In this way it 

 was sought to explain the unitary character of the 

 state of consciousness resulting from the simultaneous 

 stimulation of different sensory nerves. To every 

 part of the brain that is median and therefore has 

 no symmetrically disposed duplicate, this position of 

 honour has been assigned by one or other writer — to 

 the pineal gland by Descartes, to the pons by Spencer, 

 NO. 1849, VOL. 71] 



to the basal ganglia in general by Maudsley and 

 Carpenter, to the septum lucidum and to the third 

 ventricle by others, to some undefined region by 

 Herbart and Lotze. Under the powerful impulse of 

 this supposed necessity others, notably G. H. Lewes, 

 E. V. Hartmann and Ed. Montgomery, have made 

 the whole brain the seiisorinm commune, assuming 

 that the specific mode of vibration initiated in each 

 kind of sensory nerve thrills throughout the whole or 

 the greater part of the mass of the brain. 



In the Psycho-physik (i860) Fechner clearly exposed 

 the untenable character of all such assumptions and 

 showed that " the psychically unitary and simple are 

 resultants from physical manifolds, the physically 

 manifold gives rise to a unitary or simple (psychical) 

 resultant." This principle was accepted by Helmholtz, 

 and by Lotze in his later writings; and the progress of 

 our knowledge of the brain achieved since that time has 

 made patent to all the impossibility of assigning the 

 psycho-physical processes, the processes immediately 

 correlated with psychical processes, to any one part or 

 " centre " of the brain. 



Nevertheless, in dealing with concrete instances of 

 unitary psychical resultants from multiple sensory 

 stimulations, as in the case of the compound colour 

 sensations or of the fusion of the effects of stimuli 

 applied simultaneously to corresponding areas of the 

 two retinae, many, perhaps most, physiologists and 

 psychologists still postulate a fusion of the underlying 

 neural processes to a unitary physical resultant. It is 

 more difficult to refute this view in such special cases 

 than to prove the erroneousness in principle of the 

 conception of a sensoriuni commune, but fortunately 

 Prof. Sherrington's recent research on the functional 

 relations of corresponding retinal points' demonstrates 

 in the clearest manner the separateness of the physio- 

 logical effects in the brain-cortex of stimuli simul- 

 taneously applied to corresponding retinal areas, the 

 instance of fusion of effects to which the doctrine of 

 physiological fusion has been most confidently and 

 plausibly applied ; and many pathological and experi- 

 mental observations bear out this view, both in this 

 case and in other similar cases of fusion of effects of 

 sensory stimuli. The principle laid down by Fechner 

 in the words quoted above may therefore be regarded 

 as well established. This principle Wundt adopts, and 

 he extends its application in a thorough-going manner 

 to the relations of neural and psychical processes in 

 general. .Assuming that every " psychical element " 

 is related in a constant manner to an accompanying 

 neural process, he asks (vol. iii., p. 775), Is there any 

 corresponding constant relation between the connec- 

 tions (Verbindiingen) of those elements and the con- 

 nections of these processes ? "It goes without say- 

 ing that this question must be answered affirmatively 

 in the sense that to all the psychical elements that are 

 comprised in a complex affection of consciousness, the 

 corresponding physical processes must also be given 

 in simultaneous connection." But that is by no 

 means to say that these physical correlates will 

 constitute a unitary resultant, which would correspond 

 to the psychical resultant. " The complex psychical 



1 See British Journal of Fsycho/o^y, pjrt i. 1Q04. 



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