EXTRACT XXVIII. B. 



ON THE PSYCHIC, OR MENTAL, BRAIN CELLS. 



SINCE writing the foregoing, we have continued to pursue 

 enquiries into the, histology and histogenesis, of that 

 neuronal area, in which the phenomena of mind proper, 

 or intellect, and cogitation, are produced, or evolved, 

 and have become possessed of the thought, and belief, 

 that the two aspects, or areas, of systemic innervation, 

 viz. the sensory, and motor, are texturally joined, and 

 functionally united, for purposes of systemic administration, 

 and co-ordination, by a central area of, mental, or quasi- 

 independent, neurons, which, for histological distinction, we 

 have named psychic^ and which, for a great part of our 

 waking time, continue active, while the other two are, 

 as it were, " switched off." Thus, during the waking 

 state, unless the sensorium is engaged receiving sensory 

 impressions, or discharging motor impulses, it follows, 

 as a functional necessity, that it must be engaged in other 

 work, conscious, and, it may be, sub-conscious, inasmuch, 

 as its absolute functional abeyance is inconsistent with 

 psychological experience, and law, and, therefore, that 

 a part of that sensorium, and neuronal economy, continues 

 to cogitate, or perform purely mental work, and to keep 

 up the continuity of the process of cerebration. In that 

 part of the process of cerebration, in which the histological 

 channels of sensory, and motor, innervation, are, for the 

 time, closed, and during which, it may be, a " connected 

 process of thought " is being, evolved, or elaborated, or 

 a general process of thinking at large indulged in, we are 

 compelled to conclude, that an area, of the central 



