_Reader._ I do not deny that, while we are thinking, our brain is doing work. I merely deny that the movements of the brain are thoughts. As long as we live, soul and body work together, and we cannot think without some organic movements accompanying the operation. This every one admits. But you suppress the thinking principle, and retain only the organic movements. How is this possible? If thought consists merely of organic movements of the brain, how does the motion begin? The brain cannot give to itself a new mode of being. To account for its movements you must point out a distinct moving power, either intrinsic or extrinsic, either a sensible object or the thinking principle itself. When the motion is received from a sensible object, the movements of the brain determine the immediate perception of the object; and when the motion results from the operation of the thinking principle, the movements of the brain determine the phantasm corresponding to the object of the actual thought. Thus immediate perception, and thought, or recollection, are both rationally explained; whilst, if the thinking subject were the brain itself, how could we recollect our past ideas? When the movement caused by an object has been superseded by the movement caused by a different object, how can it spontaneously revive? Matter is inert; and nothing but a power distinct from it can account for the spontaneous awakening of long‐forgotten thoughts. _Büchner._ Matter is inert, but is endowed with forces, and wherever there are many particles of matter they can communicate movement to one another. Hence, “in the same manner as the steam‐engine produces motion, so does the organic complication of force‐endowed materials produce in the animal body a sum of effects so interwoven as to become a unit; and is then by us called spirit, soul, thought” (p. 136). _Reader._ Pshaw! Are _spirit_, _soul_, and _thought_ synonymous? Do thoughts think? When you perceive that two and two make four, is this thought the thinking principle? And if the soul is “a sum of _mechanical_ effects so interwoven as to become a unit,” how can you avoid the consequence that the soul consists of nothing but local movement? But if the soul is local movement, it has no causality, and cannot be the principle of life; for local movement is only a change of place, and has nothing to do with perception, judgment, reasoning, or any other operation of the thinking principle. Can local movement say, _I am_? _I will?_ _I doubt?_ Can local movement recollect the past, take in the present, foresee the possible and the future? Can local movement deliberate, love, hate, say _yes_ or _no_? To these and such like questions science, reason, and experience give an unequivocal answer, which the president of a medical association should have carefully meditated before venturing to write on the subject.