SYSTEMATIC ANALYSIS OF APPARATUS. 61 



responding number of kinds of apparatus to utilize them 

 fully. 



143. DIFFERENT OBJECTS PRODUCE different kinds of 

 waves of air ; different colors of light, from different po- 

 sitions ; have different odorous or savory properties, or 

 temperatures, or density ; for if they are alike in all other 

 respects, they will be in different positions, and light will 

 come from them in different directions ; and if the mind 

 be furnished with the few kinds of apparatus necessary 

 to perceive those differences and similarities, it can learn 

 all it can know about external objects. 



144. THE MIND ALSO REQUIRES a knowledge of the 

 state of the various parts of the Body ; and that must 

 be gained by means of Sensations, produced through 

 appropriate apparatus. 



145. Two CLASSES OF SENSATORY APPARATUS ARE 

 NECESSARY ; the one called objective, external, special, or 

 the senses, because it deals with objects external to the 

 Body, is specially adapted to its purpose, and is the evi- 

 dent cause of sense ; the other, called general, internal, 

 or subjective, because it exists generally throughout the 

 internal parts of the Body, and because through it ob- 

 servations are made upon the condition of the various 

 internal parts of the subject himself. 



146. The number and kinds of organs or parts neces- 

 sary to compose each variety of Sensatory Apparatus 

 can be best appreciated after noticing the means neces- 

 sary to cause a Sensation. 



147. SENSATION is the name of a peculiar effect pro- 

 duced by a part of the Brain on the Mind, of which it 

 is conscious. 



148. How THE BRAIN ACTS upon the Mind in the 

 production of a Sensation is not known or conjectured. 



143. What do ? 144. What does ? 145. What ? Write table. 147. What 

 is? 148. How does ? 



