He seems to have had very little acquaintance even with such physiology as was current in his time.

At least, the only passage of his works, bearing on this subject, with which I am acquainted, contains nothing but a very odd version of the physiological views of Descartes:-- "When I received the relations of _resemblance_, _contiguity_, and _causation_, as principles of union among ideas, without examining into their causes, 'twas more in prosecution of my first maxim, that we must in the end rest contented with experience, than for want of something specious and plausible which I might have displayed on that subject.

'Twould have been easy to have made an imaginary dissection of the brain, and have shown why, upon our conception of any idea, the animal spirits run into all the contiguous traces and rouse up the other ideas that are related to it.

But though I have neglected any advantage which I might have drawn from this topic in explaining the relations of ideas, I am afraid I must here have recourse to it, in order to account for the mistakes that arise from these relations.

I shall therefore observe, that as the mind is endowed with the power of exciting any idea it pleases; whenever it despatches the spirits into that region of the brain in which the idea is placed; these spirits always excite the idea, when they run precisely into the proper traces and rummage that cell which belongs to the idea.