REFLEX AND INSTINCTIVE ACTIONS. 525° 
Sistine: chy iat this chivas defect 
under which the individual suffers; and then to make him 
a systematically the various movements concerned in 
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 INSTINCT AND INTELLIGENCE. 
- 692. Ir will be remembered that, when the Nervous System 
was described (Chap. x1.), 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 
hese is the class of simply Reflex actions, which are executed 
nly in respondence or answer to impressions made upon the 
rves to a ganglionic centre ; as when a Dytiscus, 
whose head has been cut off, executes swimming movements 
mmediately that its feet come in contact with water. These 
vements ‘evidently take place without any choice or direc- . 
on on the part of the animal, which, in executing them, 
'Seems like a mere machine adapted to perform certain actions 
hen certain springs are touched ; and it has been shown 
at they may be called-forth even without its consciousness. 
if these reflex movements, the Spinal Cord of Vertebrata, and 
Invertebrata the ganglia corresponding to it (in regard to 
heir connexions with the organs of locomotion, respiration, 
t.), are the instruments.—II. The second class comprehends 
jose 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- 
mess. Nevertheless, the animal in executing them is not 
guided by any perception of the object to be attained, or by 
y choice of the means by whieh it is to be accomplished ; 
t acts blindly and involuntarily, in accordance with an 
resistible impulse, implanted in it by its Creator for the 
se of causing it to do that, without or even against its 
which it would not have chosen or devised by its very 
erfect intelligence. The actions of this class are most 
