speedily render all the devotees physically incapable of testifying in behalf of their peculiar opinion, and, clearing them away, would leave no witnesses surviving but such as were signifying by deeds if not in words their hearty adherence to the popular belief. Practically, then, there may be assumed to be entire unanimity of assent to the truism that for our senses to be affected by the presence of external objects, the objects must needs be present to affect them. On all hands it is in effect admitted that in some mode or other external objects exist, but if so, and if the sensations resulting from operations performed by the bodily organs with external objects would not have resulted unless the objects had been present to operate or to be operated upon, clearly there must be resident in, or inseparably bound up with, the objects a power or powers of producing sensation in conscious mind. But the power of producing sensation, and sensation itself, are not one and the same thing, but two separate and distinct things, intrinsically distinct and locally separate. The feeling, agreeable or painful, according to its intensity, which heat occasions, is not the same thing as the heat by which it is occasioned. The twofold taste, sweet to a healthy, bitter to a distempered palate, of one and the same aliment, cannot be identical with the single property of the aliment whereby the taste is produced. In the sense of seeming red to a spectator with normally constructed eyes, and green to one who is colour-blind, a ruby or a Siberian crab is at once both red and green, but the two colours which it causes to be perceived cannot be identical with the peculiar structure, or whatever else it be, whereby the ruby or Siberian crab communicates to circumambient ether the one self-same motion that terminates in different impressions on differently constructed eyes. In these and in all cases of the kind the feeling is in the mind, the source of the feeling in matter. The one is a perception, the other a quality, and to mistake the quality, not merely for a perception, but for the very perception to which the quality gives rise; and to infer thence that the quality must likewise be in the mind, is an instance as glaring as can well be imagined of that most heinous of logical offences, the confounding of cause with effect.