216 PHILGSOPHY OF ZOOLOGY. 
ed in all the various circumstances in which they present 
themselves. ‘This power or effort of the mind is termed 
1. Attention.— Unless this power is exercised on the or- 
gans of perception, the impressions which are produced 
are confused and obscure, and speedily vanish. But, by its 
means, the organs are brought into a condition suitable to 
receive an impression and determine its nature and dura- 
tion, and preserved therein a sufficient length of time. 
In the exercise of Attention, we seldom are capable of 
employing more than one sense at atime; but can, without 
much difficulty, fix the mind on several different kinds of 
information which one sense is capable of communicating. 
Thus, we can distinguish a variety of conditions in sound, 
and the impressions produced on the organs of sight. 
But this faculty chiefly displays its peculiar nature and its 
utility, in its selective operations. ‘Thus, for example, in 
looking at a rose, I can either attend to its size, its subdivi- 
sions, colour or fragrance. The character on which I am 
said to bestow the greatest attention, is the one to which I 
direct the suitable organ of sensation with the greatest in- 
tensity, for the greatest length of time, and of which I am 
said to have the most distinct conception. Man employs 
this essential faculty of his mind, in every inquiry he makes, 
and in almost every action which he performs. Without 
its assistance and controul, no knowledge of external ob- 
jects can be gained, no train of reflection can be pursued, 
no successful bodily effort can be made. 
In the lower animals, this faculty not only exists, but dis- 
plays itself'to our observationin various ways. What is it but 
the exercise of attention, when we see a cat watching for a 
mouse, or a kestril hovering in the air? In both cases, the 
faculty now under consideration is exercising its controul 
over the organs of sight, When we witness the fox-hound 
engaged in the chace, we see attention regulating the or- 
