310 



NATURE 



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results of anatomical and physiological research as to the 

 structure and functions of the brain ; second, the facts m 

 human life unaccounted for by anatomical and physio- 

 logical science, and requiring to be assigned to a higher 

 nature." 



In these words our author indicates not merely his 

 method, but the conclusions as to the relations^ of mind 

 and brain to which his investigations have led him. 



The first six chapters deal with the anatomy and phy- 

 siology of the brain, both human and 'comparati\-e. In 

 these and "also in other parts of the work Prof. Calder- 

 •wood exhibits an extensive acquaintance with the facts of 

 cerebral anatomy, physiology, and pathology, worthy oi 

 any technical neurologist, and which reflects especial 

 credit on an author hitherto identified with purely specu- 

 lative philosophy. 



As the result of his study of the comparative anatomy 

 and physiology of the brain, he reaches the position that 

 the brains most elaborate in convolution are indicative 

 mainly of the most highly developed muscular system. The 

 development of the brain is, however, no test of "intelli- 

 gence." This, he contends, is most strikingly brought 

 out by a comparison of the brain of man and the ape. 

 " The ape, with a brain modelled like man's, and weighing 

 IS to 20 oz., shows himself active, powerful, and able to 

 assail any adrersary ; man, with a brain better developed, 

 and 10 to 15 oz. heavier, is tottering, feeble, and idiotic, 

 unable to defend himself from even a weak assailant. If 

 configuration and structure of brain afford a measure of 

 intelligence, our poor idiotic fellow-man should be so 

 much clearer in intellect and decided in action than the 

 highest specimens of apes. But it is not so" (p. 161). 



The comparison here instituted is a very fallacious one. 

 The exact formula for the relationship between brain de- 

 velopment and intelligence in different animals has yet to 

 be found. That it is not a mere matter of size is generally 

 admitted. But that the relationship is thorough-going is 

 proved by the very fact here alluded to by Prof. Calder- 

 wood, that below a certain standard of development 

 idiocy is the invariable result. The comparison should 

 not be between a microcephalic idiot and a normal ape, 

 but between a normal ape and a microcephalic one. The 

 microcephalic ape would certainly be idiotic. 



At the close of his review of the facts of cerebral ana- 

 tomy and physiology Prof. Calderwood says: "At this 

 stage it seems our only possible conclusion that anatomi- 

 cal and physiological investigation as to brain and nerve, 

 so far as they have yet been carried, afford no explanation 

 of our most ordinary intellectual exercises" (p. 216). 



He quotes with approval Prof. Tyndall's words that " the 

 passage from the physics of the brain to the correspond- 

 ing facts of consciousness is unthinkable," &c. (p. 212); 

 but not content to accept the two as correlated facts in- 

 susceptible of further simplification, he endeavours to 

 prove by " personal experience " that mind is altogether 

 distinct from brain, and of a higher and immaterial nature. 

 " That we discriminate between sensations and percep- 

 tions, and consequently form conceptions of things, are 

 facts towards the explanation of which all that is knowm 

 concerning the action of nerve-fibres and cellular sub- 

 stance contributes nothing " (p. 224). " The known laws 

 of brain action do not provide for this ; they imply that 

 the nerve system is not equal to such work" (p. 221). 

 In his chapter on "Experience as connected with 



Motor Activity" (Chapter VIII.) we find the following 

 account of the nature of volition ;— " What we mean by 

 volition or e.xercise of will-power is best shown, in the 

 first instance, by marking its contrast with nerve-action. 

 It is not that which moves the muscles, but that which 

 moves the nerve-cells to act upon the muscles. It is not 

 that which moves the limbs, but that which determines 

 that they shall be moved. In its lower and simpler aspect 

 this may be illustrated by reference to sensory activity. 

 A falling stick touches the hand, or a neighbour jostles 

 the elbow. By contact with some external body, an im- 

 pulse is given to the sensory nerve which is transmitted 

 to the sensory cells. Let us now turn to motor activity. 

 In so far as the originating power acts upon the motor 

 apparatus, its action is, in a sense, analogous to that 

 which produces a tactile impression— it operates as an 

 external power, that is, external to the apparatus. Or, 

 to take a form of expression more familiar, there comes 

 from an inner sphere, from the region of personal expe- 

 rience, an impulse which acts upon the motor cell, and 

 throws it into activity. That which acts upon the motor 

 cells is as certainly external to the system as is the object 

 which comes into contact with the sensory system. But 

 in the case of voluntary muscular activity, that which 

 operates acts directly on the cell. And what is not 

 reflex, as not being the product of movement of the 

 sensory nerve, must be accounted for by energy from 

 some other quarter, that is, from a sphere external to the 

 nerve system, though within the nature of the person" 



(p. 247). 



Such being the standpoint assumed by Prof. Calder- 

 wood in reference to the simplest forms of mental mani- 

 festation, it is unnecessary to follow him in his analysis 

 of the higher mental operations. 



He advocates essentially \ht so-called "clavier" theory, 

 that the mind is something of a higher nature and dis- 

 tinct from brain, which plays on brain as on a musical 

 instrument. If the brain is diseased, mental manifesta- 

 tions will be limited or inharmonious, but the defect is 

 purely in the instrument, and not in the performer. 



Prof. Calderwood admits that the brain is the organ of 

 the mind; that "a pure independence of mind is not 

 known in our history" (p. SU); that defective develop- 

 ment of the brain and idiocy invariably go together ; 

 that diseases of the brain are associated with mental de- 

 rangement (Chapter XIII., "Brain Disorders") and 

 deficiencies (Chapter X.. "bse of Speech"); that mind 

 has a powerful influence on body, and that mental work 

 implies physiological waste (Chapter XI., - Action and 

 Reaction of Body and Mind"); an.l yet, notwithstand- 

 ing the thoroughgoing correlation between mind and 

 brain which these and similar fads demonstrate, he pro- 

 fesses by the aid of personal experience to prove the 

 existence of something distinct from and independent of 

 the conditions of its manifestation. This process reminds 

 one very much of an attempt to lift oneself by the hair 

 of the head, or raise the chair on which one sits. Prof. 

 Calderwood cannot divest himself of his brain by personal 

 experience, nor can he give us any evidence of personal 

 experience without brain. 



He acknowledges that " however carefully we study con- 

 sciousness, we do not thereby attain to any knowledge of 

 the nerve system," and that "only by the slow and 



