CONSCIOUSNESS. 187 



and the graduated interval between the consciousness of 

 these "rational" placentals and that of the lowest 

 races of men (the Veddahs, etc.) is less than the 

 corresponding interval between these uncivilised races 

 and the highest specimens of thoughtful humanity 

 (Spinoza, Goethe, Lamarck, Darwin, etc.). Con- 

 sciousness is but a part of the higher activity of the 

 soul, and as such it is dependent on the normal 

 structure of the corresponding psychic organ, the 

 brain. 



Physiological observation and experiment deter- 

 mined twenty years ago that the particular portion 

 of the mammal-brain which we call the seat (preferably 

 the organ) of consciousness is a part of the cerebrum, 

 an area in the late-developed grey bed, or cortex, 

 which is evolved out of the convex dorsal portion of 

 the primary cerebral vesicle, the " fore-brain." Now 

 the morphological proof of this physiological thesis 

 has been successfully given by the remarkable pro- 

 gress of the microscopic anatomy of the brain, which 

 we owe to the perfect methods of research of modern 

 science (Kolliker, Flechsig, Golgi, Edinger, Weigert, 

 and others). 



The most important development is the discovery of 

 the organs of thought by Paul Flechsig, of Leipzig ; 

 he proved that in the grey bed of the brain are found 

 the four seats of the central sense-organs, or four 

 "inner spheres of sensation" — the sphere of touch 

 in the vertical lobe, the sphere of smell in the frontal 

 lobe, the sphere of sight in the occipital lobe, and the 

 sphere of hearing in the temporal lobe. Between 

 these four " sense-centres " lie the four great 

 " thought-centres," or centres of association, the 

 real organs of mental life; they are those highest 



