_Eub_.--I am not a professed materialist; but I think you treat rather too lightly the modest doubts of Locke on this subject. And without considering me as a partisan, you will, I hope, allow me to state some of the reasons which I have heard good physiologists advance in favour of that opinion to which you are so hostile. In the first accretion of the parts of animated beings they appear almost like the crystallised matter, with the simplest kind of life, scarcely sensitive. The gradual operations by which they acquire new organs and new powers, corresponding to these organs, till they arrive at full maturity, forcibly strikes the mind with the idea that the powers of life reside in the arrangement by which the organs are produced. Then, as there is a gradual increase of power corresponding to the increase of perfection of the organisation, so there is a gradual diminution of it connected with the decay of the body. As the imbecility of infancy corresponds to the weakness of organisation, so the energy of youth and the power of manhood are marked by its strength; and the feebleness and dotage of old age are in the direct ratio of the decline of the perfection of the organisation, and the mental powers in extreme old age seem destroyed at the same time with the corporeal ones, till the ultimate dissolution of the frame, when the elements are again restored to that dead nature from which they were originally derived. Then, there was a period when the greatest philosopher, statesman, or hero, that ever existed was a mere living atom, an organised form with the sole power of perception; and the combinations that a Newton formed before birth or immediately after cannot be imagined to have possessed the slightest intellectual character. If a peculiar principle be supposed necessary to intelligence, it must exist throughout animated nature. The elephant approaches nearer to man in intellectual power than the oyster does to the elephant; and a link of sensitive nature may be traced from the polypus to the philosopher. Now, in the polypus the sentient principle is divisible, 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.