Some writers have supposed that small limited areas, such as small islands, favour the production of small races by some mysterious law of appropriateness similar to that which lays down that "who drives fat oxen should himself be fat." The pygmy buffalo of the island of Celebes, the Anoa, is cited as an instance, and the pygmy men of the Andaman Islands as another. But there are plenty of facts which would lead to an exactly opposite conclusion. Gigantic tortoises are found in the Galapagos Islands and in the minute islands of the Indian Ocean, and never on the big continents. Gigantic birds bigger than ostriches abounded in the islands of New Zealand and Madagascar. Some of the tallest races of men are found in the Pacific islands, whilst the tallest European population is that of the north of the island called Great Britain. Probably the real relation of islands to the matter is that owing to their isolation and freedom from the general competition of the vast variety of living things in continental areas, they offer unoccupied territory in which either exceptionally small or exceptionally big races may flourish--if once they reach the island shelter, or are by variation produced there--without competitive interference. An important consideration in regard to the formation and segregation of a human variety or race is that mankind shows a tendency to segregate in groups, like with like. To a large extent this is true also of animals, but in man it acquires a special dominance, owing to the greater activity in him of psychical or mental influences in all his proceedings. The "cagots" of mid-France are the descendants of former leper families. They remain separated from the rest of the population, and do not now know why, nor do their hostile neighbours. Such "outcast" or "accursed" tribes and family groups are found also in Great Britain, and throughout the world. Possibly the "pygmies" owe their preservation to this tendency. Virchow regarded the Lapps as a race produced by disease--a pathological product. It is possible that former liability to disease and present immunity from it is the final explanation of the tropical pygmy race. In the United States black pigs are able to eat, without harm, a common marsh herb, the "Red-root" _Lachnanthes tinctoria_, which kills other pigs. Hence a black race is established, not because it is black, but because, in it, blackness is "the outward and visible sign of an inward and chemical grace"--that is to say, of a physiological or chemical power of resistance to, and immunity from, the poison of an otherwise nutritious plant. Such "correlations" were described by Darwin, and are of extreme importance and interest--far more so than is, at present, recognised by naturalists. I am inclined to the supposition that the obvious outward signs, the round head, bombous forehead, furry skin, and diminutive size of the pygmies are the outcome of an