REFLEX AND INSTINCTIVE ACTIONS. 525 



of power to use them aright), is to study the particular defect 

 under which the individual suffers ; and then to make him 

 practise systematically the various movements concerned in 

 the production of the sounds in question, at first separately, 

 and afterwards in combination, until he feels that his volun- 

 tary control over them is complete. 



CHAPTER XIV. 



OF DISTINCT AND INTELLIGENCE. 



692. IT will be remembered that, when the Nervous System 

 was described (Chap. XL), it was shown to be the instrument 

 of three classes of operations, each of which seems to be per- 

 formed by a distinct portion of the apparatus. I. The first of 

 these is the class of simply Reflex actions, which are executed 

 only in respondence or answer to impressions made upon the 

 nerves proceeding to a ganglionic centre ; as when a Dytiscus, 

 whose head has been cut off, executes swimming movements 

 immediately that its feet come in contact with water. These 

 movements evidently take place without any choice or direc- 

 tion on the part of the animal, which, in , executing them, 

 seems like a mere machine adapted to perform certain actions 

 when certain springs are touched ; and it has been shown 

 that they may be called-forth even without its consciousness. 

 Of these reflex movements, the Spinal Cord of Vertebrata, and 

 in Invertebrata the ganglia corresponding to it (in regard to 

 their connexions with the organs of locomotion, respiration, 

 &c.), are the instruments. II. The second class comprehends 

 those Instinctive actions, which differ from the preceding in 

 being dependent on the sensations received by the animal, 

 and in being, therefore, never performed without its conscious- 

 ness. Nevertheless, the animal in executing them is not 

 guided by any perception of the object to be attained, or by 

 any choice of the means by which it is to be accomplished ; 

 but acts blindly and involuntarily, in accordance with an 

 irresistible impulse, implanted in it by its Creator for the 

 purpose of causing it to do that, without or even against its 

 Will, which it would not have chosen or devised by its very 

 imperfect intelligence. The actions of this class are most 



