But it is quite otherwise with purely quantitative differences in nutrition. That meagre diet influences individuals unfavourably is indubitable, and we are certainly justified in considering whether this may not have an effect on the germ-cells, and one which will correspond to the changes induced on the body, so that if the poor nutrition should last through many generations an hereditary degeneration of the species would occur, which would not at once disappear though the animals were transferred to more favourable conditions. We certainly know nothing of how far the minuteness of the determinants of the germ-plasm, the whole quantity of the germ-plasm, or the reduced size of the germ-cell, may bear an internal relation to the smallness of the animal which develops therefrom, but it surely cannot be regarded as absurd to suppose that there is some such relation. There are no experiments known to me which prove that meagre diet brings about a progressive decrease in the size of the body. Carl von Voit has observed that dogs of the same litter grew to very different sizes of body according as they received abundant or scanty food, but it would be difficult to make animals small through scantiness of food and at the same time to keep them capable of reproduction, and thus proofs of the inheritance of the dwarfing are lacking. Moreover, the experiments which Nature herself has made are never quite convincing, because we never can definitely exclude the indirect effect of altered circumstances. The case of the feral horses of the Falkland Islands, so often cited since the time of Darwin, which have become small 'through the damp climate and scanty food,' seems to me, of all known cases of the kind, the one we should most readily attribute to the direct effect of continued scanty diet; but even here we cannot altogether exclude the possibility of the co-operation of adaptations of some kind to the very peculiar conditions of life in these islands, as far as the feral horses are concerned. I have not been able to find any record of more modern exact investigations either regarding these feral horses, or in regard to the others which are reared in the Falklands under conditions of domestication. Darwin himself, however, in the Journal of his famous voyage tells us much that is interesting in regard to the mammals of the Falkland Islands. Cattle and horses were brought there in 1764 by the French, and have increased greatly in numbers since that time; they roam about wild in large herds, and the cattle are strikingly large and strong, while the horses both wild and tame are rather small, and have lost so much of their original strength that they cannot be used for catching wild cattle with the lasso, and horses have to be imported from La Plata for this purpose. From this contrast between the horses and the cattle we may at least conclude that it cannot be 'scanty food' alone which causes the horses to become smaller, but that the climatic