March i i, i8t;6 



NA TURE 



437 



knowledge of the psychology of brutes, seeing that we 

 cannot directly interrogate them upon the nature of their 

 feelings or mental states. The discussion which followed 

 appears to have had the effect of somewhat modifying his 

 original views ; for these, as now stated in his book, are 

 not so severely sceptical as they were w-hen stated in 

 these columns. That is to say, he now appears to recog- 

 nise the possibility of comparative psychology as a 

 science, although its subject-matter is necessarily re- 

 stricted by the inadequacy of our "ejective" knowledge 

 of animal intelligence. 



We are in such full agreement with the w-hole essay 

 that our only criticisms upon it refer to matters of com- 

 parative detail. These are as follows : — 



Mr. Morgan gives it as his opinion that we cannot 

 conceive of matter apart from motion (p. 94), for, in 

 order to do so, we should require to conceive of matter 

 as absolutely cold, '• and of such absolutely cold matter 

 we have no knowledge." The fact, however, that we 

 have no knowledge of absolutely cold matter is no proof 

 that we are not able to conceive of matter as absolutelv 

 cold. The so-called absolute zero of temperature surely 

 admits of conception as definite as it would were it pos- 

 sible to take an actual reading of its occurrence. 



Mr. Morgan's use of the word " instinct " appears to us 

 equivocal. At one time instinctive actions are expressly 

 affirmed to mean adaptive actions of an involuntary and 

 unconscious kind (pp. 226-7) j while at another time it is 

 said " Mr. Darwin clearly shows that the satisfaction of 

 any instinctive emotion carries with it a subdued form of 

 pleasure ; while, on the other hand, if those instinctive 

 emotions be not satisfied, there results a still more marked 

 feeling of uneasiness, which is a subdued form of pain '' 

 (p. 259). Now, clearly, there can be no such thing as an 

 unconscious emotion, an unconscious form of pleasure, 

 or a '' still more marked [unconscious] feeling of uneasi- 

 ness." Mr. Morgan thus appears to have fallen into the 

 inevitable confusion which is the fate of all writers who 

 fail clearly to distinguish between instinct and reflex 

 action, or expressly to include the former term within the 

 territory of consciousness. For these reasons we cannot 

 follow the author's analysis where it leads up to the con- 

 clusion that volition is coextensive with consciousness 

 (p. 226 et seq.). We may be conscious of the sudden 

 anguish of neuralgia : can it be said that this conscious- 

 ness is due to, or accompanied by, any act of volition ? 

 Mr. Morgan would answer that with the pain there arises 

 a desire that it should cease (p. 229). But, in the first 

 place, a desire is not a volition ; and, in the next place, 

 even the desire has here no time to arise before the pain 

 is past. 



In one place where Mr. Morgan refers to the views of 

 the present writer, he represents them as differing from 

 those of Dr. Bain, while in reality no difference obtains. 

 First, he quotes the following passage from " Mental 

 Evolution in Animals ": — 



" What is the difference between the mode of operation 

 of the cerebral hemispheres and that of the lower ganglia 

 which may be taken to correspond with the great sub- 

 jective distinction between the consciousness which may 

 attend the former, and the no-consciousness which is 

 invariably characteristic of the latter.' 1 think the only 

 difference that can be pointed to is a difterence of rate or 

 time, which clearly implies that the nervous mechanism 



concerned has not been fully habituated to the perform- 

 ance of the response required. . . . Reflex action may be 

 regarded as the rapid movement of a well-oiled machine, 

 consciousness as the heat evolved by the internal friction 

 of some other machine, and psychical processes as the 

 light which is given out when such heat rises to red- 

 ness. Consciousness is but an adjunct which arises 

 when the physical process, owing to infrequency of re- 

 petition, complexity of operation, or other causes, involves 

 what I have before called ganglionic friction.'' 



Now, on this passage Mr. Morgan remarks that he 

 does not consider such ganglionic friction so important a 

 factor in the evolution of consciousness as is " the diffusion 

 of nerve-disturbance " enunciated by Dr. Bain. But surely 

 the former principle includes the latter. For it is only 

 due to this internal friction that the diffusion of nerve- 

 disturbance can be supposed to take place. If all the 

 paths of nervous discharge were freely open, the nervous 

 disturbance would course rapidly and easily along the 

 habitual channels, with comparatively little diffusion as a 

 reeult. It is only in cases where no one set of paths are 

 more readily open than other sets that alternative direc- 

 tions are offered to the flow of nervous disturbance, with 

 diffusion as a result. The resistances thus encountered — 

 or the ganglionic friction thus created — finds its measur- 

 able expression in the delay of eventual response. But 

 although ganglionic friction may arise from such "com- 

 plexity of operation " (so leading to diffusion), it may also 

 arise from " infrequency of repetition or other causes.' 

 Therefore the term ganglionic friction includes all that is 

 expressed by the term diffusion, and differs from it only 

 in being more comprehensive, or in recognising other 

 conditions of cerebral action leading to consciousness, 

 the occurrence of which is always expressed by delay. 

 George J. Romanes 



OUR BOOK SHELF 

 Spectrum Analysis. Six Lectures delhiered in 1868 

 before the Society of Apothecaries in London. By Sir 

 Henry E. Roscoe, F. R.S. Fourth Edition, Revised 

 and Considerably Enlarged by the Author and by 

 Arthur Schuster, Ph.D., F. R.S. ' (London: Macmillan 

 and Co., 1886.) 

 This is a fourth edition of a well-known book, and the 

 joint authors have evidently taken some trouble to bring 

 the present edition up to date. To this end, the arrange- 

 ment of the book, which is rather peculiar, lends itself 

 very well. The peculiarity of the arrangement to which we 

 refer is this. At the time that the lectures were first de- 

 livered, now nerirly twenty years ago, the literature of the 

 subject was so restricted that Prof Roscoe found it easy 

 and convenient to reinforce the subject-matter of each 

 lecture by reprinting, immediately after it, the particular 

 memoirs on which it had been based. Hence the first 

 edition was a very precious boon to two classes of people : 

 there was an excellent popular account of the new science, 

 and there were the complete memoirs conveniently brought 

 together for those who wished to go more deeply into the 

 subject. 



In the present edition an attempt has been made, as 

 we have said, to bring the lectures more or less up to 

 date, and considering the volume of the work which has 

 been done since 1 868, one can understand that this has 

 been no easy task. When we pass, however, from the 

 lectures to the appended memoirs so much cannot be 

 said ; indeed the interest of this part of the book is now 

 chiefly antiquarian, if we except reprints of Dr. Schuster's 

 own papers, which are given, we believe, in extcnso, 



