Taking, now, the sixty heaviest brains of persons not noted for intellectual greatness, we find the averages to be 63.2 ounces. Comparing this with the average of sixty famous men, 51.3 ounces, we find a difference in favor of imbeciles, idiots, criminals, and men of ordinary mind of 11.9 ounces. George Combe estimated that about 53.5 ounces was the average weight of the adult brain. Thus the average brain weight of all the eminent men whom we have brought into the comparison, 51.3 ounces, is below Combe's estimate of that of mankind in general. Again, the ten heaviest brains of our list of famous men give an average weight of 61.1 ounces, while the average given by the ten heaviest of the opposite class is 70.4 ounces, or 9.3 ounces greater. While our list of eminent men shows only five whose brains exceeded 58.6 ounces in weight, those of seventy-six of the common throng--seven of them idiots or imbeciles--rise above that figure. These figures augur badly for the doctrine that would attach importance to heavy brains for giving force and depth of individual character.
Phrenologists assert that each organ of a mental faculty occupies a certain position perceptible on the outside of the brain, with a definite area which they have mapped out. They also hold that each of these organs extends to the center of the base of the brain, tapering to it somewhat like a cone, having its base turned toward the outer world. They make no account of the fissures, the intervening sulci and anfractuosities that must cut many of these supposed cones, some at right and some at oblique angles. Then the large, long cavities or ventricles intercept and would hinder many of them from reaching the central, basilar part of the brain. The anatomical structure of the brain thus appears fatal to this theory of the organs.
Large and complicated convolutions of the brain with deep sulci have been regarded by some persons as inseparable from superior powers of mind. The supposition is erroneous and groundless. The rodents, such as beavers, squirrels, rats, mice, etc., have but little brain and no convolutions whatsoever;[46] yet the beaver exhibits great foresight, economy, industry, and mechanical skill in building his dam, erecting his house, and storing up bark as food for the winter. Moreover, these animals live in societies and labor in union by ingenious methods for a common purpose, with nice judgment. "So great a variety of labors," says Dr. Leuret, "is needed for the constructions carried on by the beaver; they include so many instances of well-made choice, so many accidental difficulties are surmounted by these animals, that it is impossible not to recognize in their actions the characteristics of a rather high intelligence."[47] The sheep has a much larger brain than the beaver, with numerous and complete convolutions, yet it is one of the most stupid of domestic animals. Again, though birds have convolutions in the cerebellum, they have none in the cerebrum, and yet they are more capable of education than any living beings except the human race. The eagle is complete master of the lamb; the magpie, the hawk, the raven, and the parrot with his talking powers, are not excelled in sagacity by the dog, the horse, or the elephant, notwithstanding the latter animals have brains of superior size and elaborate convolutions.