The law of selection brought forward by Darwin and Wallace may be stated as follows:--No two offspring of the same parents are quite similar to each other, indeed they often vary to a considerable extent. Under the conditions in which they live, some of these offspring will have an advantage over the rest, dependent upon an inborn peculiarity. Inasmuch, therefore, as more progeny are produced than can ever survive, those most fitted to these surroundings will have the better chance of living. These will, in larger numbers, perpetuate the race and transmit their inborn qualities to the race, thus gradually eliminating the less suitable ones. Keeping to the case of the giraffe, Darwin and Wallace would explain the length of the neck somewhat as follows: With Lamarck they believe that the ancestor was short-necked, but the subsequent elongation they would explain in quite another way. They would take for granted that there are times when grass and foliage are scarce, that short-necked animals would soon exhaust the herbage and shrubs, but that the taller shrubs and trees would afford subsistence to animals with a higher reach. Amongst the ancestral giraffes those born with the longest necks would at such times have an advantage over the rest, who in large numbers would die out. The longer necked ones, more suited to their environment, would perpetuate their inborn quality of long-neckedness: of the next generation those again with the longest necks would survive, and so on. The Darwin and Wallace school of thinkers would, I quite believe, be prepared to state that by attention to education it would be possible to improve the mental qualities of the race, but they would teach that this improvement could only take place provided that the system made it possible for the clever man and woman to earn a better livelihood, _marry early_, and _have large families_, while the stupid ones should produce fewer children, a condition which at present is far from being the rule. [Illustration: FIG. 1. Diagram to illustrate: A, the transmission of acquired characters, B, modification of type by natural selection. In A an individual of rounded proportions, at the top of the diagram, has two children. Environment is represented by a board with holes through which they must pass. In so doing they become thinner, transmit the thinness to their children, and so on. In B, a man of rounded proportions has two sons who vary, one being fat, the other thin. The fat one cannot get through the hole in the board; but the thin one does, has children who again vary, the thin one having an advantage.] _Three Ideas involved in Selection._