and from one polypus or one earthworm may be formed two or three, all of which become perfect animals, and have perception and volition; therefore, at least, the sentient principle has this property in common with matter, that it is divisible.  Then to these difficulties add the dependence of all the higher faculties of the mind upon the state of the brain; remember that not only all the intellectual powers, but even sensibility is destroyed by the pressure of a little blood upon the cerebellum, and the difficulties increase.  Call to mind likewise the suspension of animation in cases similar to that of our friend, when there are no signs of life and when animation returns only with the return of organic action.  Surely in all these instances everything which you consider as belonging to spirit appears in intimate dependence upon the arrangements and properties of matter.

The Unknown.—­The arguments you have used are those which are generally employed by physiologists.  They have weight in appearance, but not in reality.  They prove that a certain perfection of the machinery of the body is essential to the exercise of the powers of the mind, but they do not prove that the machine is the mind.  Without the eye there can be no sensations of vision, and without the brain there could be no recollected visible ideas; but neither the optic nerve nor the brain can be considered as the percipient principle—­they are but the instruments of a power which has nothing in common with them.  What may be said of the nervous system may be applied to a different part of the frame; stop the motion of the heart, and sensibility and life cease, yet the living principle is not in the heart, nor in the arterial blood which it sends to every part of the system.  A savage who saw the operation of a number of power-looms weaving stockings cease at once on the stopping of the motion of a wheel, might well imagine that the motive force was in the wheel; he could not divine that it more immediately depended upon the steam, and ultimately upon a fire below a concealed boiler.  The philosopher sees the fire which is the cause of the motion of this complicated machinery, so unintelligible to the savage; but both are equally ignorant of the divine fire which is the cause of the mechanism of organised structures.  Profoundly ignorant on this subject, all that we can do is to give a history of our own minds.  The external world or matter is to us in fact nothing but a heap or cluster of sensations; and, in looking back to the memory of our own being, we find one principle, which may be called the monad, or self, constantly present, intimately associated with a particular class of sensations, which we call our own body or organs.  These organs are connected with other sensations, and move, as it were, with them in circles of existence, quitting for a time some trains of sensation to return to others; but the monad is always present.  We can fix no beginning