THE BRAIN. 425 



The mental endowments chiefly concerned in the manifestations of 

 intelligence are memory, reason, and judgment. 



Memory is the simplest and most essential of these faculties for the 

 performance of intelligent acts. The recollection of names, and of the 

 objects to which they belong, is indispensable for even the use of articu- 

 late language ; and a defective memory often seems the immediate 

 cause of the incapacity of idiotic children. Memory is constantly 

 essential in the ordinary occupations of life, in enabling us to retain 

 past impressions as a guide for immediate or future acts. 



Reason may be considered as the ability to appreciate the nature of 

 nervous impressions, and to refer them to their external source. This 

 is quite different from the simple power of perception, which may con- 

 tinue unimpaired after extensive injury of the hemispheres. The mental 

 action excited by an impression on the senses transfers our attention 

 from the sensation to its cause ; and when this action is prompt and 

 effectual, we acquire an idea both of the origin of the impression and 

 its significance. The perfection of this quality consists in the certainty 

 with which it appreciates the relation between cause and effect and 

 the relative importance of different phenomena. It is deficient or 

 absent in idiots, and they consequently cannot avoid dangers, or provide 

 for their necessities. For the same reason it is useless to punish an 

 idiot, because, although he may feel the pain inflicted, he does not refer 

 it as a consequence to any previous act of his own. A similar defi- 

 ciency in the insane or the weak-minded produces a want of power to 

 comprehend the importance and connection of different events. They 

 are said to be " unreasonable," because they expect results which are 

 unlikely to follow from certain causes, and because they assume the 

 existence of causes which are not indicated by the results. 



Judgment is the faculty by which appropriate means are selected for 

 the accomplishment of a particular end. Its exercise requires the- 

 existence of reason and memory, which supply the necessary conditions 

 upon which it is based ; while its own action is one which looks to the 

 future rather than to the past. An individual in whom the judgment is 

 well developed employs, under the guidance of experience, means which 

 are adapted to the end in view ; one who is deficient in this respect 

 resorts to means which are insufficient or inappropriate, and is conse- 

 quently unsuccessful. Whether the act performed in this manner be a 

 simple mechanical operation, like that of shutting a door to exclude 

 the cold, or a complicated plan involving many parts, the mental 

 process is the same in kind, and differs only in degree ; its essential 

 character being that it is an intelligent act, based on an understanding 

 of the previous conditions, and intended to accomplish a definite result. 



It is evident that all such manifestations of intelligence are in the 

 nature of reflex actions. Their starting point is a sensation coming 

 from without, giving rise in the nervous system to a series of internal 

 operations, and terminating in an intelligent volitional impulse. This 

 is reflected from within outward, and thus finally calls into action the 



