XIV.] 



OEGANIC FUNCTIONS. 



163 



organic scale. Thus, all organisms whatever perform spon- 

 taneous motions : all animals, except perhaps some of the 

 very lowest, move in response to a stimulus : all sentient 

 animals move in response to sensations, and probably all 

 animals that have any mental power higher than mere 

 sensation are capable of voluntary motion. 



We now come to the sensory functions. "We have seen Sensory 

 that the nervous system is, essentially and primarily, a 

 part of the animal apparatus for the transformation of 

 energy; that it is in the highest degree probable that 

 every action of the nerves whatever, as well as of the 

 muscles, is accompanied by a transformation of energy ; 

 and that in sensation and thought the transformation of 

 vital energy is probably into heat. 



I have enumerated four successive gradations of the 

 motor functions. The gradations of the sensory functions 

 are almost infinite : beginning with simple sensation, and 

 going on through those functions of memory, perception, 

 and thought, which constitute Mind. All these have their Mind, 

 starting-point in sensation : they consist of simple ele- 

 ments, which, however, form endlessly varied combinations. 

 In the logical order, this would be the place for a treatise 

 on mental science ; bu.t I prefer to keep to the customary 

 order, and, so far as possible, to treat of mental science 

 apart, and after biology; and for the present I will 

 enumerate all the sensory functions under the two heads 

 of sensation and mind. 



All the organic functions may consequently be enume- Tabular 



rated in the following tabular form.: — 



summary. 



Formative or vegetative func- 

 tions, essentially consisting 

 in the transformation of 

 matter. 



Animal functions essentially 

 consisting in the transforma- 

 tion of energy. 



Chemical. 

 Structural. 



Motor. 



Sensory. 

 M 2 



Formation of organic 



compounds. 

 Formation of tissue. 

 Formation of organs. 



Spontaneous. 



Reflex. 



Consensual. 



Voluntary. 



Sensation. 



Mind. 



