_Sensation as distinguished from Perception._--According to the view now presented, _sensation_, as distinguished from _perception_, is the _simple feeling_ which results from a certain affection of the organism. It is known to us merely as feeling. Perception takes cognizance of the feeling _as an affection of the organism_, and also of the organism as thus affected, and consequently as external to the me, extended, having parts, etc. It apprehends also objects external to the organism itself limiting and affecting its movements. Sensation is the indispensable condition of perception. If there were no sensation, there would be no perception. The one does not precede, however, and the other follow in order of time, but the one being given, the other is given along with it. The two do not, however, coexist in equal strength, but in the relation, as stated by Hamilton, of _inverse ratio_; that is, beyond a certain point, the stronger the sensation, the weaker the perception, and _vice versâ_. _Sensation as an Affection of the Mind._--It has been common to speak of sensation as lying wholly in the mind. Primarily, however, it is an affection of the nervous organism, and through that organism, as thus affected, an impression is made on the mind. If it were not for the mind present with the organism, and susceptible of impression from it, and thus cognizant of changes in it, the same changes might be produced in the organism as now, but we should be entirely unconscious of and insensible to them. In certain states of the system this actually happens, as in sound sleep, the magnetic state, the state produced by certain medicinal agents as ether, chloroform, opium, and the intoxicating drugs of the East. In those cases, the connection between the mind and the nervous organism seems to be in some manner interrupted or suspended, and consequently there is for the time no sensation. The nerves may be irritated, divided even, and still no pain is felt. It is not true, however, that the sensation is wholly in the mind. It is in the living animated organism, as pervaded by the mind or spiritual principle, mysteriously present in every part of that organism, and cognizant of its changes; and neither the body alone, nor the mind alone, can be said to possess this faculty, but the two united in that complex mysterious unity which constitutes our present being. § III.--ANALYSIS AND CLASSIFICATION OF THE QUALITIES OF BODIES.