Feb. 7, 1884] 



NA TURE 



33i 



Readers of the earlier writings of Mr. Romanes are well 

 aware that he possesses a considerable skill in psycho- 

 logical analysis ; and the present volume amply justifies 

 the high expectations in this respect which his other works 

 had excited. He shows acuteness and now and again 

 subtlety. But ingenuity is invariably kept in check by 

 that too uncommon quality, sound common sense. He 

 does not strain after originality, but rather takes pleasure 

 in affiliating his views on the doctrines of recognised 

 masters of the science. The reader has throughout the 

 conviction that the writer has a disinterested enthusiasm 

 for his subject, and cares much more for adding to the 

 store of %yell-ascertained truth than for adding to his own 

 reputation as a contributor to this result. In all this he 

 seems to have caught something of the spirit of his 

 favourite master, Charles Darwin, of whose valuable 

 work in animal psychology the present volume is to so 

 large an extent a continuation. 



At the very outset Mr. Romanes has to face a question 

 which makes unusual demands on the inquirer's sobriety 

 of judgment. What are we to include under the head 

 of mind? How far down in the zoological scale can we 

 confidently maintain that mind is to be found ? And by 

 what criterion are we to ascertain its presence ? The 

 student of psjchology need not be reminded that even 

 competent writers have grown confused in seeking to 

 demarcate the area of mental phenomena, whether as 

 presenting themselves in connection with a single organ- 

 ism, or with the sum of organic beings. A trained psy- 

 chologist like G. H. Lewes used the terms " sensibility " 

 and " sentience" in a way that left his readers perplexed 

 as to whether he was speaking of a psychical phenomenon 

 properly so called, that is, a mode of feeling, or simply 

 of a physiological phenomenon, actions of the nervous 

 system or nervous processes. Mr. Romanes has steered 

 clear of this confusion. He rightly criticises Lewes's use 

 of the term "sensation," and confines it to its proper 

 subjective signification. Mind being thus coextensive 

 with feeling or states of consciousness, the author pro- 

 ceeds to lay down a criterion for ascertaining its presence 

 in any given case. It is as follows : — " Does the organism 

 learn to make new adjustments, or to modify old ones, in 

 accordance with the results of its own individual expe- 

 rience .' " Otherwise expressed, it is the manife^tation of 

 choice, choice being proved by " the antecedent uncer- 

 tainty of adjustive action." In laying down this test, 

 however, Mr. Romanes is careful to point out its imper- 

 fections. " It is not rigidly exclusive, either, on the one 

 hand, of a possibly mental character in apparently non- 

 mental adjustments, or, conversely, of a possibly non- 

 mental character in apparently mental adjustments." 

 That is to say, it is a rough test sufficient for practical 

 purposes, and eminently in accordance with the dicta of 

 common sense. 



After a brief account of the structure and function of 

 nerve-tissue, and of the growing complexity of nerve- 

 structures as evidenced by the double result, compound- 

 ing of mental elements and compounding of muscular 

 elements, the writer proceeds to discuss what he terms 

 the root-principles of mind. He has already told us that 

 the criterion of mind is choice. He now considers what 

 is involved in the simplest type of choice. Being a 

 mental quality, it must have its physiological correlative. 



This the author takes to be what he variously calls "the 

 power of discriminating between stimuli irresfiec/ive of 

 tlicir relative inecluiiiical intensities" the power of " selec- 

 tive discrimination," of "discriminative excitability," &c. 

 It is illustrated by the capability of a sea-anemone which 

 had been surrounded by a turmoil of water, after a time 

 of expanding its tentacles on contact with a solid body. 

 This implies the discrimination of qualitatively unlike 

 stimuli. Each of the organs of special sense has as its 

 function " the rooting out, selecting, or discriminating 

 the particular kind of stimulation to which its responsive 

 action is appropriate." This power of discrimination is 

 regarded as the root-principle of mind. This doctrine 

 has a certain resemblance to the theory of Mr. Spencer 

 and Dr. Bain, that the feeling of difference is the funda- 

 mental mode of consciousness. But the author is very 

 explicit in saying that the discrimination he speaks of is 

 a physiological and not a psychological property. Indeed, 

 he allows that it manifests itself in plants, that is to say, 

 much lower down in the scale of organisms than mind 

 can be supposed to reach. It may, however, occur to the 

 reader that the property is not even peculiar to organic 

 structures. Does not a piano manifest just this selective 

 discrimination (to qualitatively unlike stimuli) when its 

 several strings pick out and resonate to the appropriate 

 vibrations of a composite mass of sound ? And is it not 

 easy to conceive an artificial mechanism showing such 

 discrimination in a far higher degree than the lower 

 grades of animals .'' It maybe urged, further, that what 

 choice, as previously defined by Mr. Romanes, requires 

 as its correlative is a germ of conscious discrimination. 

 A new adjustive action, not provided for by the inherited 

 nervous structures, seems to involve some vague con- 

 sciousness of a difl'erence between the new and the old, 

 the exceptional and the usual, circumstances. Mr. Romanes 

 might not improbably meet these difficulties by saying 

 that in calling this physiological discrimination the root- 

 principle of mind he simply means to single out the most 

 important property of nerve-structures, the development 

 of which up to a certain point is an antecedent condition 

 of the appearance of mind or consciousness. But even 

 then it would be hard to see why this was exclusively 

 erected into the root-principle of mind to the disregard of 

 another property, retentiveness or memory, which Hering 

 and others have shown to be a property of all organic 

 structure, and the importance of which, indeed, the 

 author seems to allow later on in his work. 



In order to com(jlete the author's account of the physio- 

 logical conditions of mind it is necessary to add that he 

 supposes consciousness to arise when the time occupied 

 by the nervous process, or the interval between sensory 

 stimulation and muscular action reaches a certain magni- 

 tude. Mere complexity of nervous actions does not in- 

 volve consciousness, as we may see in the case of highly 

 compound refle.xes. To use the author's graphic language, 

 consciousness involves as its immediate physiological 

 condition a ganglionic "friction" or "state of turmoil." 

 This increase of time " implies that the nervous mecha- 

 nism concerned has not been fully habituated to the 

 performance of the response required." As more complex 

 organisms are evolved, and the stimuli playing on them 

 become in consequence more varied, this insufficiency of 

 mechanical arrangements and consequent rise of gang- 



