Later, and added to these inherited mechanisms--often interfering with them and putting an end to them--are the mechanisms of the second step. These are mechanisms arising from individual experience; they depend on memory--the inscription on "the tablets of the mind," of the experience that this follows that. They control movement and action, usurping the privilege of the previously omnipotent inherited mechanisms or instincts. This second step in the development of mind requires an excessive quantity of brain-cells. It only makes its appearance at all in animals with large brains, and reaches a far greater development in man even than in the apes, his brain being from twice to three times the size of that of the largest living ape. This use of memory and individual experience--instead of an inherited mechanism, which is the same in every member of the species--is obviously a great advantage in the struggle for existence. There are traces of it in some of the cuttlefish and insects, but even in the fishes and reptiles among living vertebrates it is of small account, and the small brain carries on its work by good, sound, inherited mechanisms or instincts, but learns nothing, comprehends nothing! In the birds we see a little--a very little--more capacity for "learning by individual experience," and it is only in the larger and later mammals that educability, or the power of learning by individual experience, becomes of serious importance. All the larger living mammals--horse, cattle, sheep, rhinoceros, tapir--have acquired an enormous increase in the size of their brains--as much as six or eight times the volume of that of their extinct ancestors whose bones and brain cavities we find fossilized in the Tertiary strata. Man has by far the biggest brain of all these animals, and has a unique degree of educability, together with the fewest instincts or in-born hereditary mechanisms among animals. He has practically to learn by individual experience--and therefore in the form best suited to his individual requirements--a host of most important actions and behaviours which even monkeys as well as dogs and sheep and horses never have to "learn," but proceed to put in practice as soon as they are born, or, at any rate, without any preliminary process of experiment and effort. Man is the one highly "educable" animal. In consequence of his large brain and its roomy memory he can be, and is--even when a "savage"--educated. Monkeys and dogs have only small "educability" as compared with man, though more than have reptiles or fishes. Man's mind is, therefore, in this essential feature different from that of animals. The modern mammals with brains as much as eight times the bulk of their early Tertiary ancestors have, it is true, acquired "educability" and the power of storing _individual_ experience as "memory," but their memory is far less extensive than that of man, and though its guidance is of great value to them it acts