4 o6 BIOLOGICAL PHYSICS 



to the end that hereby man may attain a condition of 

 mental and moral advancement, to which there is no 

 approach elsewhere observable throughout the whole 

 kingdom of animated nature. 



These cerebral areas of intellectualism would seem to 

 be confined within the structures situated above the 

 tentorium cerebelli, or in that region of the great central 

 nervous system situated within the anterior, middle, and 

 posterior cephalic or brain spaces, where also the great 

 connecting centres of sensory and motor nervine activities 

 become linked up, united to, and blended with those of 

 mind proper. 



The manner of the union of these kindred, but dis- 

 tinctive nerve elements, however, is a subject too subtle 

 and transcendental to do more than mention ; neverthe- 

 less, we are persuaded, from the analogies which are 

 observable in somewhat kindred relationships, that 

 materio-dynamic conditions regulate and determine it, 

 on the same consummate physiological, and we may add, 

 psychological, lines, that can be so lucidly traced through 

 great areas of that complex and far-reaching subject of 

 brain and nerve anatomy. Within the cerebrum, material 

 agencies and mechanisms co-exist, capable of acting singly 

 or conjointly, accordingly as the mental and bodily 

 materio-dynamic conditions require and necessitate, and 

 accordingly as they are actuated by altogether central, 

 peripheral, or combined nerve energy ; besides modes of 

 nervine activity which are more or less constantly mani- 

 fested, consisting of purely mental, sensory, and motor 

 impulses, each, it may be, occurring independently by 

 itself, or in conjunction with, or succession to, others. 

 Much discussion of the subject of neuronal growth, and 

 nerve cell disposition of axis-cylinder substance, has been 

 indulged in by neurologists, but it cannot yet be said 

 that more than tentative opinion prevails on it ; thus, we 

 may suppose that strands of axis-cylinder substance, 

 emanating from the first, or earliest, spongioblastic cortical 

 ranges of the ectoderm or the most remote cortical nerve 

 cells, and from the most distal and profound ranges of 

 centrally originating cells, within the domain of the 

 mentally endowed areas of the succeeding embryonic 



