"According to Frederic Cuvier, who has so clearly distinguished between instinct and intelligence in animals, 'instinct is a natural and inherent faculty, like feeling, irritability, or intelligence. The wolf and the fox who recognize the traps in which they have been caught, and who avoid them; the dog and the horse, who understand the meaning of several of our words, and who obey us,--thereby show _intelligence_. The dog who hides the remains of his dinner, the bee who constructs his cell, the bird who builds his nest, act only from _instinct_. Even man has instincts: it is a special instinct which leads the new-born child to suck. But, in man, almost every thing is accomplished by intelligence; and intelligence supplements instinct. The opposite is true of animals: their instinct is given them as a supplement to their intelligence.'"--Flourens: Analytical Summary of the Observations of F. Cuvier. "We can form a clear idea of instinct only by admitting that animals have in their _sensorium_, images or innate and constant sensations, which influence their actions in the same manner that ordinary and accidental sensations commonly do. It is a sort of dream, or vision, which always follows them and in all which relates to instinct they may be regarded as somnambulists."--F. Cuvier: Introduction to the Animal Kingdom. Intelligence and instinct being common, then, though in different degrees, to animals and man, what is the distinguishing characteristic of the latter? According to F. Cuvier, it is REFLECTION OR THE POWER OF INTELLECTUALLY CONSIDERING OUR OWN MODIFICATIONS BY A SURVEY OF OURSELVES. This lacks clearness, and requires an explanation. If we grant intelligence to animals, we must also grant them, in some degree, reflection; for, the first cannot exist without the second, as F. Cuvier himself has proved by numerous examples. But notice that the learned observer defines the kind of reflection which distinguishes us from the animals as the POWER OF CONSIDERING OUR OWN MODIFICATIONS. This I shall endeavour to interpret, by developing to the best of my ability the laconism of the philosophical naturalist.