696 Dynamic Theory. 



greater the intensity of the action, the more of these incidental and un- 

 necessary accompaniments attend it. That is to say, a stimulus, if in- 

 tense, reaches further and affects more organs than when it is mild. All 

 these circumstances taken together go to prove the practical unity of the 

 whole cortex. It is one in the same sense in which the external world 

 is one. Built up as it is by the combined, intertwined and associated 

 energies that are reflected from the environment, it imitates that envi- 

 ronment in the intricate maze of connections by which every part is 

 bound to and associated with all the rest. Anatomists tell us that if 

 the cortex be examined microscopically no breaks of connection or 

 boundary lines are anywhere discernible, and < ' that beyond a slight dif- 

 ference in thickness, and in the number of alternate la} T ers composing 

 it, the sheet of gray matter is as absolutely homogeneous as the rind of 

 an orange, or the plaster upon your wall. " 



Those tracts of the cortex which are specialized organs to sense im- 

 pressions, as sight, hearing, &c. , and to definite motor action of partic- 

 ular parts, as jaws, arms, legs, &c. , have become so established through 

 the direct connections which exist between these tracts and the corres- 

 ponding external sense and motor organs. These connections are con- 

 firmed to us and our posterity through the habit of the race and heredi- 

 tary transmission, and do not depend upon personal or individual edu- 

 cation and experience. The organs of perceptions and of ideas, on the 

 other hand, have not these exclusive connections in either direction, but 

 depending, as they often do, upon more than one class of sensoiy im- 

 pressions, they must be connected more or less completely wi-th all. 

 The ideas of an artist, we may suppose, are intimately dependent upon 

 sight memories, and those of a musician upon hearing memories, but 

 they are also dependent upon motor memories of jaws, tongue, and 

 limbs for their development and expression, so that the connections of 

 the organs of these ideas are not definite and fixed, and may, by educa- 

 tion, become formed in greatly differing ways. Where one generation 

 after another has been educated in the same ideas, no doubt the organs 

 of ideas do get more or less definite and settled connections, so as to be- 

 come, to some extent, hereditary and fixed organs, so that we find the 

 son "take after" the father in the bias and bent of his ideas, and con- 

 sequently his character, as well as in his features. It is these interme- 

 dial organs of ideas which are subject to the formative power of indi- 

 vidual experience and education. The formation of the organs proceeds 

 automatically, following the differentiation of the sense tracts, and vary- 

 ing according to the mode of that differentiation. They become a sort 

 of transcript of the part of the environment to which we have been ex- 

 posed ; a transcript which the environment is constantly at work upon, 

 altering, adding to, expunging, and amending, day by day as long as 

 we live and have our senses. 



