66 rSY Clio LOGY. 



tor's hand, and yet be proved by circumstantial evidence to 

 exist all the while iu a split-off condition, quite as ' ejective ' * 

 to the rest of the subject's mind as that mind is to the mind 

 of the bystanders.f The lower centres themselves may 

 conceivably all the while have a split-off consciousness of 

 their own, similarly ejective to the cortex-consciousness ; 

 but whether they have it or not can never be known from 

 merely introspective evidence. Meanwhile the fact that 

 occipital destruction in man may cause a blindness which 

 is apjjarently absolute (no feeling remaining either of light 

 or dark over one half of the field of view), would lead us to 

 sujjpose that if our lower optical centres, the corpora 

 quadrigemina, and thalami, do have any consciousness, it 

 is at all events a consciousness which does not mix with 

 that which accompanies the cortical activities, and which 

 has nothing to do with our personal Self. In lower 

 animals this may not be so much the case. The traces of 

 sight found (supra, p. 46) in dogs and monkeys whose occip- 

 ital lobes were entirely destroyed, may possibly have been 

 due to the fact that the lower centres of these animals saw, 

 and that what they saw was not ejective but objective to 

 the remaining cortex, i.e. it formed part of one and the 

 same inner world with the things which that cortex per- 

 ceived. It may be, however, that the phenomena were due 

 to the fact that in these animals the cortical ' centres ' for 

 vision reach outside of the occipital zone, and that destruc- 

 tion of the latter fails to remove them as completely as in 

 man. This, as we know% is the opinion of the experiment- 

 ers themselves. For practical purposes, nevertheless, and 

 limiting the meaning of the word consciousness to the per- 

 sonal self of the individual, we can pretty confidently answer 

 the question prefixed to this paragraph by saying that the 

 cortex is the sole organ of consciousness in man.j^ If there 



* For this word, see T. K. Clifford's Lectures and Essays (1879), vol. ii. 

 p. 72. 



f See below, Chapter VIII. 



X Cf. Ferrier's Functions, pp. 120, 147, 414. See also Vulpian: Legons 

 sur la Physiol, du Syst. Nerveux, p. .^48; Luciani u. Seppili, op. cit. pp. 

 404-5; H. Maudsley: Physiology of Mind (1876), pp. 138 ff.. 197 ff., and 

 241 ff. In G. H. Lewes's Physical Basis of :Mind, Problem IV: ' The Reflex 

 Theory,' a very full history of the question is given. 



