THE CEREBRUM, AND ITS FUNCTIONS. 755 



materials and a continued action of external agencies, the Mind, when it has 

 been once called into activity, and has become stored with ideas, may remain 

 active, and may develop new relations and combinations amongst these, after 

 the complete closure of the sensorial inlets by which new ideas can be excited 

 ah externo. Such is, in fact, what is continually going on in the state of Dream- 

 ing; but examples yet more remarkable are furnished in the vivid conceptions 

 which may be formed of a landscape or a picture, from oral description, by 

 those who have once enjoyed sight; or in the composition of music, even such 

 as involves new combinations of sounds, by those who have become deaf as in 

 the well-known case of Beethoven. The mind thus feeds, as it were, upon the 

 store which has been laid up during the activity of its sensory organs ; but 

 instead of diminishing, like material food, these ideas become more and more 

 vivid, the oftener they are made the subjects of attention. 



787. The seat of the Sensational Consciousness, as already shown, is indicated 

 by a large mass of evidence to lie in the Sensory Ganglia, which are the real 

 centres of the Nerves of Sense ; and we may fairly conclude that, when not in- 

 terrupted in the upward course already indicated, the changes which occur there 

 give rise to a new excitement of nerve-force, which is propagated along the as- 

 cending nerve-fibres to the vesicular matter that forms the surface of the Cerebral 

 Hemispheres; and that it is only when they arrive at the ultimate termination 

 of these fibres in the latter, that these impressions give rise to those changes 

 which are in the first instance instrumental in the formation of Ideas 1 and sub- 

 sequently in the higher Intellectual Operations. These operations themselves 

 become the source of new changes in the condition of the Nervous substance ; 

 and an excitation of nerve-force takes place as their result, which, transmitted 

 downwards to the sensorial tract at the base of the Cerebrum, gives rise through 

 it to respondent movements ( 759). Now it is an inquiry of considerable in- 

 terest, both in its psychological and its physiological relations, whether the 

 Cerebrum is itself endowed with consciousness ; that is, whether we become 

 conscious of changes which take place in the condition of its substance, so long 

 as these changes are limited to itself. At first sight it would appear to be a 

 very startling proposition, that the organ of the intellectual operations is not 

 itself endowed with consciousness ; but a careful consideration of its relations 

 to the Sensory Ganglia will tend to show that there is no d priori absurdity in 

 such a notion. For, if the relation of the vesicular matter of the Cerebral 

 Hemispheres to the Sensorial Centres, be anatomically the same as that which 

 is borne to these centres by the Retina, or by any other peripheral expansion of 



1 The Author cannot here enter into the discussion which has been the subject of so 

 many abstruse and labored Metaphysical discussions, how far Ideas are to be considered 

 as " transformed sensations," or as " states or affections of the consciousness" which, 

 though primarily excited by sensations, may have nothing in common with them. It will 

 be sufficient for him to express his own conviction, that the latter is the only consistent 

 mode of viewing the subject ; and that the Idea can no more correctly be described as a 

 " transformed sensation," than sensation itself could be designated as a transformed im- 

 pression. The one is antecedent, the other consequent ; the one is the force which, acting 

 on a certain prepared organization, evokes a further change, just as a mechanical or elec- 

 trical stimulus applied to a muscle calls it into contraction. The notion of Condillac and 

 the Sensational School of Psychologists, that ideas are " transformed sensations," appears 

 to have been based upon the consideration of those ideas alone which are most nearly allied 

 to Sensations in their nature, being the immediate psychical representations of objective 

 or concrete realities. But it cannot be legitimately held of those abstract or general ideas, 

 which have no objective representatives, and which are the products of mental operations 

 that are by no means truly described by the term transformation. Thus the idea of the 

 invariability of the laws of Nature arises out of a constant succession of new and diversified 

 phenomena; as has been beautifully shown by Prof. Oersted, in his Essay on " The Spirit- 

 ual in the Material," which forms the first section of his Treatise on " The Soul in Nature," 

 recently ^iven to the English public. 



