292 



NA TURE 



[July 28, 1887 



the " product " of the nervous mass of the brain in any 

 sense of the word corresponding to that which we rightly 

 apply to the various secretions of the body, involves us 

 at once, it is held, in the grossest absurdities ; while the 

 theory that claims that all mental phenomena, whatever 

 their varied characteristic shading, have exact equiva- 

 lents, as it were, in specific forms of the nerve-commo- 

 tion of the living brain is marked by its " surprising 

 audacity." " Standing on a slender basis of real fact, it 

 makes a leap into the dark which carries it centuries in 

 advance of where the light of modern research is now 

 clearly shining." The author, however, by no means 

 rejects, he strongly contends for, a causal nexus as exist- 

 ing between brain and mind. He regards the term organ 

 (or instrument) of the mind, as applied to the body, as 

 particularly calculated to emphasize the relation of the 

 ideas and volitions which arise in consciousness to the 

 control of the muscular apparatus. He will have nothing 

 to do with monism, but contends that psycho-physical 

 science, simply observing the facts and building on them, 

 establishes the dualism of brain and mind. "We affirm, 

 then," he says, " that we are entitled to say : The changes 

 of the brain are a amse of the states of consciousness ; 

 and the mind behaves as it does behave, because of the 

 behaviour of the molecules of the brain." " We affirm 

 also that we are equally entitled to say : The states of 

 consciousness are a cause of the molecular condition and 

 changes of the nervous mass of the brain, and through it 

 of the other tissues and organs of the body." 



So far, in dealing with the third part, we have perhaps 

 made it appear that, in the author's view, the correlation 

 is complete. And the passages we have quoted seem to 

 justify this view. But many other passages reject such an 

 interpretation with scorn. " In investigating the cor- 

 relations which undoubtedly exist between the nervous 

 mechanism and the phenomena of consciousness, it is 

 found that some of these phenomena imply activities of 

 the mind which do not admit, in any sense of the word, of 

 being thus correlated." "Judgment itself is a fonii of 

 mental phenomena for the essential part of which no 

 physical equivalent can be discovered or even conceived 

 of." "To account for this boundless expansion of the 

 activities of consciousness (in the early years of child- 

 hood), with its surprising new factors and mysterious 

 grounds of synthesis and assumption, by proposing an 

 hypothesis of ' dynamical associations ' among the particles 

 of nervous substance in the brain, is a deification of im- 

 potency." " Not one of the higher acts of feeling, know- 

 ing, or willing, so far as its sui generis character is 

 concerned, admits of being correlated with, or represented 

 under, any of the conceivable modes of the motion and 

 relation of molecules of nervous substance." 



It would seem, then, that the author plays rather fast 

 and loose with this correlation, as indeed is apt to be the 

 fashion with dualists. We doubt whether he is justified 

 in saying that psycho-physical science establishes the 

 dualism of brain and mind. Here, it seems to us, the 

 writer's usual caution forsakes him. Idealism, material- 

 ism, occasionalism, dualism, monism, are none of them 

 theories that are in any likeHhood of being " established '' 

 for many a long day. They are of the nature of beliefs ; 

 and strong as is his advocacy of the dualistic creed the 



author falls into error if he dreams of its speedy establish- 

 ment. We could wish that he had squarely faced the 

 difficulties which the acceptance of the dualistic 

 hypothesis entails, a few of which are but barely men- 

 tioned on page 597. These and many others may not be 

 difficulties to him ; but surely he who would establish a 

 doctrine should meet half-way such difficulties as are likely 

 to trouble unbelievers. We could wish, too, that he had 

 given us a more detailed criticism of the monistic creed 

 which he rejects. To ask why the double-faced unity 

 (the human being) manifests itself both in physical and 

 mental states — "one being, in two wholly incomparable 

 modes of manifestation " — and to say that monism has to 

 undertake the task of showing how the one reality can 

 appear under these two phenomenal forms of being — 

 matter and mind — is surely not a very powerful or acute 

 criticism. There are many hows and whys which can 

 only be answered by quietly pointing to the facts. We 

 do not say that monism can in this way be "established " ; 

 but we regard the criticism as weak. 



Nor are we impressed with the force of the argument 

 upon which so much stress is laid, that for certain higher 

 mental activities no physiological correlate can be con- 

 ceived. It seems to us that, if anywhere, the inconceiv- 

 ability comes in at the very beginning. If once the 

 conceivability of a correlation between a nerve-commo- 

 tion of any kind and a state of consciousness be admitted, 

 there need be no further talk of inconceivability in the 

 matter. There lies the rub : elsewhere we only find 

 questions of degree and of relative complexity. 



We cannot take leave of this valuable and important 

 work without expressing our sense of its ability, its 

 thoroughness, and its candour. There is no other book 

 in the English language that covers its ground. 



C. Ll. M. 



OUR BOOK SHELF. 



'TKe:'.Essentials of Histology. By E. A. Schafer, F.R.S. 

 ■ Second Edition. (London : Longmans, Green, and 



Co., 1887.) 

 This edition is, in several respects, an improvement on 

 the first. The volume is less bulky, and there are some 

 useful additions to the text so as to bring this up to date, 

 especially as regards the methods of histological study. 

 There are seventeen valuable illustrations added. The 

 omission in the first edition of references to the authors 

 of the illustrations has, we are glad to see, been corrected 

 in this edition. 



On the whole, we think the book a clear exposition of 

 the present state of human histology, and, as such, it will 

 prove useful to students and teachers. E. Klein. 



Aluminium: its History, Occurrence, Properties, Metal- 

 lurgy, and Applications, including its Alloys. By 

 Joseph W. Richards. i2mo, pp. 346 (Philadelphia: 

 Band. London: Sampson Low and Co. 1887.) j^l 

 This volume is mainly a compilation based upon dS 

 late H. St. Claire Deville's treatise published in 1858, 

 and the newer work by Dr. Mierzinski in Hartleben's 

 " Chemisch-Technische Bibliothek," which appeared in 

 1883. As no special work on aluminium had previously 

 appeared in English, we agree with the author that no 

 apology is necessary in presenting it. The subject has 

 been systematically treated both from the scientific and 





<i. 



