Up to a recent period it was supposed that the weight or size of the brain was the chief physical element in mental superiority. It is now known, that has little to do with it. Not a few men of distinguished parts, such as Liebig, Gambetta, Tiedemann, etc., have had brains decidedly below the average in weight, while, on the other hand, many with large brains have led unimportant lives. This is also the case with races, for although the African negro is below the European in his cranial capacity, the Fuegian, decidedly below the African in mental development, has a brain larger than either of the other races. Obviously, both the cubical content and weight of the brain depend much on the general size, stature, and weight of the body; and no one has been found who pretends that the biggest man is also the ablest. We are almost compelled, therefore, to accept as correct the conclusion reached by Lapouge and others, that not the size but the molecular constitution of the brain is finally decisive of intellectual power; and this is a trait which up to the present time has eluded analysis. This is not inconsistent with holding that where other proportions are the same, a larger, more complex brain is generally significant of higher mental powers; and that a well-balanced skull, with orthognathic features and moderate facial development, are indications favourable for the psychical possessions of the individual or the group. The _shape_ would seem to be more significant than the weight of the brain. Of all the elements of gross cerebral anatomy it appears to be that most indicative of mental power. This is a recent discovery of craniologists, the entire meaning of which has not yet been worked out. It is due to the researches of Ammon and Lapouge within the last decade, and to the anthropologist promises solutions of various obscure problems in the cultural growth of the species. These observers have ascertained, by many thousand measurements on the living and the dead, that those persons who, as a class, are best adapted to the high and continued strain of modern city and competitive life, have skulls in that shape termed “subdolichocephalic,” which means that their brains have a prevailing and fixed spatial relation of their parts, a relation, no doubt, which is the most favourable to the general and prolonged activity of those nerve cells which we know are the seat of psychical function. Such persons in youth stand at the head in the school, they take the prizes in examinations, they carry off the honours in intellectual contests, they are leaders in the learned professions, they are the self-created “upper class,” and, what is equally noteworthy, in the unhealthy atmosphere of great cities they outlive their associates with other shapes of brain.