At the same time the horse and the gun were introduced.

With extraordinary rapidity the Indian adapted himself to a new mode of existence, a grassland life, complicated by the fact that the relentless pressure of the invaders gave it a predatory turn which it might otherwise have lacked.
Something very similar, though neither conditions nor consequences were quite the same, occurred in the pampas of South America, where horse-Indians like the Patagonians, who seem at first sight the indigenous outcrop of the very soil, are really the recent by-product of an intrusive culture.
* * * * * And now let us hark back to southern Asia with its two reservoirs of life, India and China, and between them a jutting promontory pointing the way to the Indonesian archipelago, and thence onward farther still to the wide-flung Austral region with its myriad lands ranging in size from a continent to a coral-atoll.

Here we have a nursery of seamen on a vaster scale than in the Mediterranean; for remember that from this point man spread, by way of the sea, from Easter Island in the Eastern Pacific right away to Madagascar, where we find Javanese immigrants, and negroes who are probably Papuan, whilst the language is of a Malayo-Polynesian type.
India and China each well-nigh deserve the status of geographical provinces on their own account.

Each is an area of settlement; and, once there is settlement, there is a cultural influence which co-operates with the environment to weed out immigrant forms; as we see, for example, in Egypt, where a characteristic physical type, or rather pair of types, a coarser and a finer, has apparently persisted, despite the constant influx of other races, from the dawn of its long history.

India, however, and China have both suffered so much invasion from the Eurasian northland, and at the same time are of such great extent and comprise such diverse physical conditions, that they have, in the course of the long years, sent forth very various broods of men to seek their fortunes in the south-east.
Nor must we ignore the possibility of an earlier movement in the opposite direction.