Consctousn ess. 1 H ; 7 



pended upon it in the shape of a current of air. The function of the 

 brain cell is silent also, unless the energy of a body outside of itself is 

 expended upon it. Each single cell is probably adapted to produce a 

 single tone of motion so that a fluto represents eight or twelve cells to- 

 gether, constituting a group of elementar}' organs. 



The functions of the different tissues of the body are carried on, in some 

 degree, by the disintegration and consumption of the tissue itself. The 

 energy of muscle contraction is finished by the decomposition of parts 

 of the muscle itself. The same appears to be true of nerves, and is 

 certainly true of brain cells, so that all sorts of brain action, including 

 consciousness, involves the wear and tear of the cells themselves, and 

 so demands and brings to them an increased supply of blood to furnish 

 material for renewals and repairs. Even a sound made near a sleeping 

 person, which does not wake him up, will increase the flow of blood to 

 the brain. (See pages 517 and 815.) But the function of sensation or 

 consciousness is further proved to be a mode of physical energy by the 

 fact that it is one term in a series of plrysical actions, each of which is 

 set going by one which preceded it, and upon its termination inaugurates 

 another to succeed it. If sensation were simply a sort of ornamental 

 function blossoming out from the other mental action, and never of it- 

 self doing any work, the case would not be so clear as it is. But, as 

 we saw in chapter 70, the sensations are potent factors in the inaugura- 

 tion of motor nerve action. In fact, pleasurable and painful sensations 

 (re-experienced through memory) constitute the entire force behind the 

 will in purposive actions. 



It was shown in chapter 70 that the formation of the will is followed 

 by an efferent nerve current towards a muscle. Unless the will 

 were itself a mode of nervous energy, this could not happen, since no 

 new motion can come into existence except as the consequent of an an- 

 tecedent motion. The will, therefore, is a mode of motion, and, by the 

 law just mentioned, must be preceded and initiated by other motion. 

 We found the will to be made up by, and to be, in fact, the resultant 

 of, other energies called sensations ; these sensations consisting of recol- 

 lections of pleasure and pain accompanied by other sensations of ideas, 

 or their recollection. The former comprise the more energetic and ag- 

 gressive stimulations, and the latter act chiefly as modifiers in restrain- 

 ing or accelerating, and in selecting time, place and means. But, at all 

 events, these sensations are genuine nervous stimulations, and are as 

 certainly terms of physical energy as are the stimulations from luminous, 

 sonorous or odorous bodies. Thus, whether we approach consciousness 

 from the afferent side or the efferent side, we reach the same conclusion. 

 It arises as a sequel to the expenditure of energy, and it transfers its 

 energy when a will is formed, and when it is not, the sensation is turned 



