In _tubercles_ of the brain, it is curious that _memory_ is the faculty chiefly influenced; it is sometimes rendered dull, while the fancy is vivid,—often more perfect and retentive. Brain, however, can no more be considered as mind itself, than _retina_ sight, or than the sealing-wax can be identical with the electricity residing in it. For if we look at the brain of a brute, we see how closely it resembles our own; then, if we reflect on human intellect and brute instinct, we must all believe at once that there is some diviner thing breathed into us than the _anima brutorum_ of Aristotle, something more than the mere vitality,— “Spiritus intus alit, totamque infusa per artus Mens agitat molem.” Brain is therefore the _habitat_ of mind, the workings of which cannot be indicated without it; for, as the material world would be intact without a sense, so there can be no mortal evidence of mind without a brain, which is indeed the sense of the spirit. Thus, without adopting the creed of the _Hyloist_, the _moderate_ materialist,—that the mind cannot have, during the life of the body, even a momentary existence independent of matter,—I believe, that when this matter is in a state of repose, mind is perfectly passive to _our cognizance_. IDA. It is with diffidence, Evelyn, that I enter this arena with a physician, learned in the body; but is there no danger in this doctrine? does it not imply the office of a _gland_,—that brain is the _origin_ of soul, and that its function was the _secretion of thought_. EV. Such is the timid error of the mere metaphysician, Ida. There is no such danger; for, remember, if there _be_ secretion, it is the _soul_ which _directs_. Many a thought is referred to things which we cannot bring into contact with our consciousness,—_except by the brain_. Dr. Gall writes of a gentleman, whose forehead was far more elevated on the right side than the left; and he deeply regretted that with this left side he could never think. And Spurzheim, of an Irish gentleman, who has the left side of the forehead the least developed by four lines,—he also could not think with that side, as indeed I have before hinted. I may tell you the brain is _double_, and _one_ healthy _hemisphere_ is sufficient, as the organ of mind, if pain or encroachment of the opposite, when diseased, does not destroy life, and this especially when it is a _chronic_ change, or exists from birth; so that I have often seen one hemisphere of the brain a pulpy bag of water, and yet vitality and many signs of intellect may still exist; nay, even if the _whole_ brain be reduced to one _medullary_ bag, _animal_ life shall for some time be preserved.