APHORISMS AND REFLECTIONS 75 



tainment of truth in physical science, answers this 

 question for us. In the head of the lobster there lies 

 a small mass of that peculiar tissue which is known 

 as nervous substance. Cords of similar matter 

 connect this brain of the lobster, directly or indirectly, 

 with the muscles. Now, if these communicating 

 cords are cut, the brain remaining entire, the power 

 of exerting what we call voluntary motion in the 

 parts below the section is destroyed ; and, on the 

 other hand, if, the cords remaining entire, the brain 

 mass be destroyed, the same voluntary mobility is 

 equally lost. Whence the inevitable conclusion is, 

 that the power of originating these motions resides 

 in the brain and is propagated along the nervous 

 cords. 



In the higher animals the phenomena which attend 

 this transmission have been investigated, and the 

 exertion of the peculiar energy which resides in the 

 nerves has been found to be accompanied by a 

 disturbance of the electrical state of their molecules. 



If we could exactly estimate the signification of 

 this disturbance ; if we could obtain the value of 

 a given exertion of nerve force by determining the 

 quantity of electricity, or of heat, of which it is 

 the equivalent ; if we could ascertain upon what 

 arrangement, or other condition of the molecules of 

 matter, the manifestation of the nervous and 

 muscular energies depends (and doubtless science 

 will some day or other ascertain these points), 

 physiologists would have attained their ultimate 

 goal in this direction ; they would have determined 

 the relation of the motive force of animals to the 

 other forms of force found in nature ; and if the 

 same process had been successfully performed for 

 all the operations which are carried on in, and by, 

 the animal frame, physiology would be perfect, and 

 the facts of morphology and distribution would be 

 deducible from the laws which physiologists had 

 established, combined with those determining the 

 condition of the surrounding universe. 



