Consciousness. 977 



brates there appears to be by no means so complete a centralization of 

 the function as in even the lower vertebrates, while in the mammals and 

 man it is generally assumed that it is concentrated exclusively, or 

 almost so, in the brain. In the brain are located the chief centers of 

 memory and thought. The greater part of our consciousness is made 

 up of sensations of thought and memory. The organs of such sensa- 

 tions are probably located in the neighborhood of the organs from 

 which they receive their stimulation, that is in the cerebrum. So also, 

 the organs of direct sensation for sight, smell, taste, hearing, and 

 touch by the tongue, have their organs of sensibility in the brain. 



It has been pointed out (page 270) that the process of differentiation 

 is one in which one portion of an organism, or organ, is selected by the 

 kinetic agency to receive the bulk of its stimulations, while the rest of 

 such organism remains without attention or stimulation of that sort, the 

 effect being that such specially stimulated portion becomes improved in 

 its function, while the neglected portion loses such responsive pliancy as 

 it may have possessed. Supposing that sensibility was originally in- 

 H IK led with impression, and that its seat was in the locality in which 

 the impressions were made, that is, in the external sense organs, the 

 process of differentiation has separated the functions, and while allow- 

 ing the kinetic impression still to pass through the sense organ, analyzes 

 it after it gets through, one part going to form an organ of sensibility, 

 and another to form an organ of an idea. That such differentiation 

 might in the course of time become perfect and absolute, is proved by 

 the example of the function of contractility, which, in the lowest or- 

 ganisms, belongs to all the parts alike, but which in the higher has be- 

 come greatly varied, some parts, as certain muscles, being extremely 

 contractile, while others are inertly contractile, and still others, as nerves 

 and bones, not contractile at all. That sensibility may have likewise 

 become separated from its original associations in different degrees, is 

 antecedently probable, and appears to be indicated by the facts. 



There are two sides to the body, each of which is exposed in its own 

 way to the influence of kinetic agencies, namely the inside and the out- 

 side. We are but little conscious of the operations which go on in the 

 inside, and of many of them we are not conscious at all. This means 

 that such sensibility as accompanies these operations has its seat in the 

 plexuses and ganglions of the S3 r mpathetic system, rather than in those 

 of the brain. The great semilunar ganglion and solar plexus situated 

 behind the stomach are no doubt centers of sensibility as well as gov- 

 ernors of visceral motor action. The solar plexus is sometimes called 

 the " cerebrum of the abdomen." This is a case of local self-govern- 

 ment. Although there is nervous connection between these centers and 

 the brain, still except in special cases there is no transfer between them 



