Among the best lectures of the volume, both for sense and brilliancy, are those on the “Conduct of the Understanding,” the “Faculties of Animals and Men,” “Habit,” and “Wit and Humor.” In these Sydney Smith exhibits both his power of rapid analysis and his power of clearly perceiving the essential points of the subjects he discusses. The lecture on the “Faculties of Animals and Men,” is a sort of humorous philosophical poem in prose, the beauty of the humor being as striking as its laughable quality. He commences with observing that he would do no injustice to the poor brutes, especially as they have “no professors to revenge their cause by lecturing on our faculties;” and he is so perfectly satisfied with the superiority of men to animals, that he sees no reason why he should not give the latter full credit for what “few fragments of soul and tatters of understanding they may really possess.” His settled opinion is, that baboons and blue apes will never rival mankind in understanding or imagination, though he confesses that he has sometimes felt a little uneasy at Exeter ’change, “from contrasting the monkeys with the ’prentice boys who are teasing them;” but a few pages of Locke, or a few lines of Milton, always restored him to his tranquil belief in the superiority of man. He then proceeds to give a humorous statement of the various opinions held by philosophers on the physiology of brutes, emphasising especially the theory of Père Bougeant, a Jesuit, that each animal is animated by a separate and distinct devil; “that not only this was the case with respect to cats, which have long been known to be very favorite residences of familiar spirits, but that a particular devil swam with every turbot, grazed with every ox, soared with every lark, dived with every duck, and was roasted with every chicken.” Smith then goes on to define and illustrate instinct, with an analysis as fine as the humor is exquisite. Instinct he considers as an animal’s unconscious use of means which are subservient to an end, in contradistinction to reason, which is a conscious use of those means and a perception of their relation to the end. The examples are all stated in Smith’s peculiar manner. It would take, he says, “a senior wrangler at Cambridge ten hours a day, for three years together, to know enough mathematics for the calculation of these problems, with which not only every queen bee, but every _under-graduate grub_, is acquainted the moment it is born.”