Note 20 — FREDERIC THE GREAT’S EULOGY ON JULIEN OFFRAY DE LA METTRIE.

In general, the form and the structure of the brains of quadrupeds are almost the same as those of the brain of man; the same shape, the same arrangement everywhere, with this essential difference, that of all the animals man is the one whose brain is largest, and, in proportion to its mass, more convoluted than the brain of any other animal; then come the monkey, the beaver, the elephant, the dog, the fox, the cat. These animals are most like man, for among them, too, one notes the same progressive analogy in relation to the corpus callosum in which Lancisi—anticipating the late M. de la Peyronie20—established the seat of the soul. The latter, however, illustrated the theory by innumerable experiments. Next after all the quadrupeds, birds have the largest brains. Fish have large heads, but these are void of sense, like the heads of many men. Fish have no corpus callosum, and very little brain, while insects entirely lack brain.