GENERAL CONCLUSIONS. 121 



e ego,' the sensation is sufficient for my belief that it is due to the 

 reaction of lines of force from outside-centres upon lines of force 

 put into action from inside-centres. But I have no ground for 

 calling the one ' material,' and the other ' immaterial,' or either, 

 or both. The same result has followed my attempts to analyse 

 all sensations and volitions, i. e. I know of nothing outside 

 myself of which I can have any clearer knowledge by calling it 

 ' material,' than I have of that which originates force from within 

 myself, by calling it an ( immaterial ' entity, mental principle, or 

 soul. 



But, so it is ; in the endeavour to clearly comprehend and 

 explain the functions of the combination of forces called ' brain,' 

 the physiologist is hindered and troubled by the views of the 

 nature of those cerebral forces which the needs of dogmatic 

 theology have imposed on mankind. 



How long physiologists would have entertained the notion of 

 a c life,' or ' vital principle,' as a distinct entity, if freed from this 

 baneful influence, may be questioned ; but it can be truly affirmed 

 that physiology has now established, and does accept, the truth 

 of that statement of Locke — e the life, whether of a material or 

 immaterial substance, is not the substance itself, but an affection 

 of it.' l Religion, pure and undefiled, can best answer, how far 

 it is righteous or just to charge a neighbour with being un- 

 sound in his principles who holds the term i life ' to be a sound 



1 cccxxxvi". vol. i. p. 761. As the authority of a Physiologist and late President 

 of the Royal Society may be cited for ascribing such vital phenomena to an invisible 

 ' mental principle,' (a) I unwillingly refer to the remark by which Sir B. Brodie meets 

 the obvious objection of the divisibility, without destruction, of acrite organisms : — 'It 

 is true that one of our most celebrated modern physiologists, from observing the 

 multiplication of polypi by the mere division of the animal, has come to the conclusion 

 that the mental principle, which to our conceptions presents itself as being so pre- 

 eminently, above all other things in nature, one and indivisible, is nevertheless itself 

 divisible, not less than the corporeal fabric with which it is appreciated.' (p. 115.) 

 The reader, eager for new light and guidance toward truth, naturally here expects the 

 facts and arguments exposing the weakness or fallacy of the inference deduced from 

 the polype-phenomena. The sole remark is a charge of that kind called ' argumcntum 

 ad hominem.' ' But it is to be observed' (proceeds Sir B. B.) 'that, great as is the 

 authority of Muller generally in questions of physiology, in the present instance he 

 is not quite an unprejudiced witness, inclined as he is to the pantheistic theory,' &c. 

 (p. 116.) Now, the charge is untrue; and, were it otherwise, affects not the point in 

 question. Johannes Muller was of the school of inductive physiologists, opposed to 

 Oken and others of the school of Schelling. He would not accept even the ' vertebral 

 theory of the skull,' or ' general homologies ; ' but adhered to the party of Cuvier : 

 he lived and died a sincere member of the Roman Catholic Church. Brodie's notior 

 of a 'mental principle' seems to be a combination of 'vital principle' and 'soul,' 

 irvevfia and tyvxh. 



(a) Brodie's, Sir B., ' Psychological Enquiries,' 12mo. 1854, pp. 103, 115, 167. 



