May 21, 1874] 



NATURE 



41 



indeed, he quotes Mr. Mill's Autobiography in his 

 prefnce to show that the great necessarian himself 

 wavered in his belief. He clearly thinks the explanation 

 of human conduct offered by those who reject the theory 

 of the independence, or rather the selj -dependence, of the 

 Will, inadequate. They would say that the unconscious 

 operationof causes proceeds independently of the conscious 

 conviction of the individual ; that however much we may 

 think that of two lines of conduct before us, either is 

 equally possible for the human Will, yet, as a fact, we 

 invariably follow the one to the exclusion of the other ; 

 the result, as it were, proves the cause, the apparent ulti- 

 mate choice is the real physical consequent of antecedents 

 engrafted in our nature, and acting in an invariable se- 

 quence, though it is true, as shown by Mr. Mill in the 

 sixth book of his Logic, that Science is not sufficiently ad- 

 vanced to enable us to predict successfully the course of 

 human action in any case, owing to the much greater 

 complexity of the influences which operate in determining 

 sociological phenomena when compared with other 

 forms of activity. The necessarian philosopher would 

 say that the operation of the Will is really nothing more 

 than the force of the stronger motive asserting itself. 

 Dr. Carpenter, and with him is the majority of mankind, 

 says that the Will itself determines from within us which 

 motive shall be the preponderating one. 



But the chief merit of Dr. Carpenter's book lies, as we 

 have said, in the explanation of the nexus which binds 

 together the physical and the psychical elements in human 

 nature. The well-known authority of what he says on 

 such a subject constitutes the main value of his work. It 

 is not too often that a great physiologist has turned his 

 attention to mental phenomena, and we therefore welcome 

 all the more gratefully any addition to the number of those 

 who base their psychology on an exhaustive analysis of 

 the functions and modes of action of the nervous system. 

 In the first and second chapters of his book -the back- 

 bone, if we may so call it, of the work — Dr. Carpenter 

 unravels carefully and exhaustively, step by step, all the 

 interdependences of the nervous system and the psy- 

 chical states. Without entering on all the mysteries of 

 nervous ganglia and afferent and motor fibres, or the phy- 

 siological comparison of Articulata and Vertebrata, we 

 would say generally that Dr. Carpenter divides bodily 

 movements in man into three classes : — (i) The prima- 

 rily automatic ; (2) the secondarily automatic ; and (3) 

 the volitional. Of these the first two " are performed in 

 respondencc to an internal prompting of which we may 

 or may not be conscious, and arc not dependent on any 

 preformed intention, being executed 'mechanically'; while 

 the last are called forth by a distinct effort of Will, and 

 are directed to the execution of a definite purpose." But 

 though thus clearly laying down the doctrine of the self- 

 determining power of the Will, the author somewhat 

 qualifies it afterwards, when he says that " even in the 

 most purely Volitional movements the Will does not 

 directly produce the result, but plays, as it were, upon the 

 Automatic apparatus by which the requisite nervo-mus- 

 cular combination is brought into action." 



The conclusion at which our author arrives as to the 

 general relations of mind and body is, in his own neatly- 

 expressed words, " that the actions of our minds, in so 

 far as they are carried on without any interference 



from our Will, may be considered as ' Functions of the 

 Brnin.'" These Functions of the Brain and of the 

 Nervous System which supplies the brain with the 

 materials which it works up into sensations and ideas, 

 are lucidly and exhaustively expounded in the second and 

 longest chapter of the work, in which the element oi 

 pure physiology preponderates, and into which we do not 

 intend to enter, as no short summary of it can fairly re- 

 present its contents. Suffice it to say that in this part ol 

 the book Dr. Carpenter shows that the amount of intelli- 

 gence (not instinct) shown by an animal is in a direct 

 ratio to the relative size of the cerebrum and the sen- 

 sorium, which latter organ in man is nearly eclipsed by 

 the superimposed cerebral hemispheres, " the instrument 

 of our psychical or inner life ; " that the cerebrum is not 

 concerned in the ordinary performance of our automatic 

 movements, though in many cases it exercises control 

 over them ; its power, however, does not extend so far as 

 to enable it to interfere with " the nervous system of 

 organic life," or sympathetic system. The ruling monarch 

 here at last meets with constitutional checks. It can 

 exert no modifying influence on the " nutritive opera- 

 tions ; " they, together with the rest of the sympathetic 

 system, would rather seem to obey another power when 

 they obey at all, the power, namely, of the emotions, which 

 so often rebel against the Will, being, so to speak, the 

 insurrectionary element which breaks in upon the digni- 

 fied controlling influence of that thinking, purposeful, 

 though sometimes eccentric monarch. 



It is impossible in the short limits of a review to enter 

 into the discussion of the part played by Attention, 

 Sensation, Perception, and other physiological conditions 

 in the production of mental results. These are all 

 minutely treated of by our author, who carries us on in 

 an easy progress from one to another with enviable 

 clearness. 



In treating of the succession of ideas Dr. Carpenter 

 follows the doctrines of Prof. Bain in relation to the 

 Laws of Association, and acknowledges the debt he owes 

 to that most conscientious philosopher. All students of 

 Prof. Bain's works on Mental Science are already 

 familiar with the Laws of Contiguity and Similarity as 

 explaining the principles of association of ideas, and we 

 need not dwell further on them. The section which 

 deals with Ideo-motor action is very interesting as leading 

 us into the region of the marvellous. Ideo-motor action 

 may be defined to be " the direct manifestations of idea- 

 tional states, excited to .1 certain measure of intensity, or, 

 in physiological language, reflex actions of the cerebrum.'' 

 It is in this definition that we find the true key to the 

 phenomena of table-turning and spirit-rapping, when 

 practised by those who bring no dishonest arts to bear 

 in their experiments. From this definition we should 

 deductively infer that the revelations which reward those 

 who take part in such experiments must be, as is in fact 

 the case, in spite of assertions to the contrary, revelations 

 of some matter known to at least one of the party en- 

 gaged in the seance^ whose mental activity and the play 

 of w!v-se ideas, apai't from any exercise of Will, may in- 

 fluence the muscular movements directly and the more 

 easily, inasmuch as the strained state of the hands on such 

 occasions, after being stretched out for several minutes, 

 renders them the easy and unresisting instruments of the 



