DIFFERENT NERVOUS SYSTEMS VARIOUSLY AFFECTED BY SIMILAR
IMPRESSIONS.
"Thus the odour of a cat, or the effluvia of mutton, the one imperceptible, the other grateful to the generality of persons, has caused individuals to fall on the ground as though bereaved of life, or to have their whole frame agitated by convulsions. Substances which induce disease in one person or animal, do not induce disease in others[44]."
IMPORTANCE OF OPINIONS.
"Thinking being inevitable, we ought, as I said, to be solicitous to think correctly. Opinions are equally the natural result of thought, and the cause of conduct. If errors of thought terminated in opinions, they would be of less consequence; but a slight deviation from the line of rectitude in thought may lead to a most distant and disastrous aberration from that line in action. I own I cannot readily believe any one who tells me he has formed no opinion on subjects which must have engaged and interested his attention. Persons both of sceptical and credulous characters form opinions, and we have in general some principal opinion, to which we connect the rest, and to which we make them subservient; and this has a great influence on all our conduct. Doubt and uncertainty are so fatiguing to the human mind, by keeping it in continual action, that it will and must rest somewhere; and if so, our inquiry ought to be where it may rest most securely and comfortably to itself, and with most advantage to others.
"In the uncertainty of opinions, wisdom would counsel us to adopt those which have a tendency to produce beneficial actions."
INDEPENDENCE OF MIND ON LIFE AS ARISING OUT OF THE IDEA
THAT LIFE WAS SUPERADDED TO ORGANIZATION—HIS DISPOSITION
TO ALLEGORY.
"If I may be allowed to express myself allegorically with regard to our intellectual operations, I would say that the mind chooses for itself some little spot or district, where it erects a dwelling, which it furnishes and decorates with the various materials it collects. Of many apartments contained in it, there is one to which it is most partial, where it chiefly reposes, and where it sometimes indulges its visionary fancies. At the same time, it employs itself in cultivating the surrounding grounds, raising little articles for intellectual traffic with its neighbours, or perhaps some produce worthy to be deposited amongst the general stores of human knowledge. Thus my mind rests at peace in thinking on the subject of life, as it has been taught by Mr. Hunter; and I am visionary enough to imagine that if these opinions should become so established as to be generally admitted by philosophers, that if they once saw reason to believe that life was something of an invisible and active nature superadded to organization, they would then see equal reason to believe that mind might be superadded to life, as life is to structure. They would then, indeed, still further perceive how mind and matter might reciprocally operate on each other by means of an intervening substance. Thus, even, would physiological researches enforce the belief which I say is natural to man: that, in addition to his bodily frame, he possesses a sensitive, intelligent, and independent mind—an opinion which tends in an eminent degree to produce virtuous, honourable, and useful actions[45]."