The question has been raised on several occasions when the size of a people has been mentioned in connection with the nature of their food, whether size is not entirely a racial characteristic, and is inherited, rather than being determined by such agencies as nutrition. It seems to me that we have some very good evidence on this point in the histories of our rat families described in the preceding chapter. When the nutrition of these animals fell just under a certain standard, there was no easily observable sign of malnutrition, their appearance and fertility remaining such that they would be judged by anyone to be "normal," yet the size diminished from generation to generation. This is not, of course, set forth as an inheritance of an acquired character, but only as evidence that physically inferior parents tend to pass on their defective constitution to their offspring. The prompt increase in size of Japanese children born in California and fed upon the products of its farms, over the sizes characteristic of children of the same ages in Japan, would seem to harmonize well with the view which we have come to hold concerning the quality of the Oriental diet. Horses introduced into the Shetland and Orkney Islands have degenerated in size and that size is inherited in their offspring. Here again we see the effects of such a scanty and somewhat inadequate food supply that the animals are stunted in their growth. Perhaps it is more accurate to say that their food supply is sufficiently scant and precarious in the winter season to interfere with their growth, and that their small size is due to permanent stunting from periodic starvation through several generations. The inferior physical development of these horses to-day must be admitted, and is certainly not due in any great measure to artificial selection. In another region of the world where pasturage is abundant throughout the year, there is every probability that the size of these animals would increase.