And it seems to me that the aim of elementary metaphysical study might henceforth become more practical than that of any other science. For in hitherto taking little cognizance of the limitation of thought by the structure of the body, we have surely also lost sight of the power of certain modes of thought over the processes of that structure. Taking, for instance, the emotion of anger, of which the cephalopoda are indeed as capable as we are, but inferior to us in being unable to decide whether they do well to be angry or not, I do not think the chemical effect of that emotion on the particles of the blood, in decomposing and otherwise paralyzing or debilitating them, has been sufficiently examined, nor the actual quantity of nervous energy which a fit of anger of given violence withdraws from the body and restores to space, neither the correlative power of volition in restraining the passion, or in directing the choice of salutary thought, as of salutary herbs on streams. And even we painters, who dare not call ourselves capable of thought, are capable of choice in more or less salutary vision. In the degree in which we lose such power of choice in vision, so that the spectral phenomena which are the materials of our industry present themselves under forms beyond our control, we become insane; and although for all our best work a certain degree of this insanity is necessary, and the first occurring conceptions are uncommanded, as in dreams, we have, when in health, always instantaneous power of accepting some, refusing others, perfecting the outlines and colors of those we wish to keep, and arranging them in such relations as we choose. 304. And unquestionably the forms of the body which painters instinctively recognize as best, and call "beautiful," are so far under the command of the plastic force of voluntary thought, that the original and future authority of such a plastic force over the whole of creation cannot but seem to painters a direct, though not a certain influence; and they would at once give their adherence to the statement made many years since in his opening lectures in Oxford by the present Regius Professor of Medicine (as far as I can recollect approximately, in these terms)--that "it is quite as logical, and far more easy, to conceive of original anima as adapting itself to forms of substance, than of original substance as adapting to itself modes of mind."