We learn, in the second place, that the cultivated plants are all immigrants from the south-east—their native home being in South-eastern Europe and Asia Minor. We shall afterward see that this is true of the domestic animals also. There can be but one explanation for this. The ancient inhabitants of Europe must have come from that direction, and brought with them the plants they had cultivated in their eastern homes, and the animals they had reduced to their service. The traces of agriculture thus found in Switzerland are by no means confined to that country. In other countries of Europe, such as England and France, we also find proofs that men cultivated the earth. In localities where we do not find the grain itself, we find their rude mills, or mealing stones, which as plainly indicate a knowledge of the agricultural art as the presence of the cereals themselves.23 As we have stated, Neolithic man in Europe possessed domestic animals. He was not only a cultivator of the soil, but he was a herdsman as well; and he kept herds of oxen, sheep, and goats. Droves of hogs fattened on the nuts of the forest, and the dog associated with man in keeping and protecting these domestic animals. We know that the Swiss Lake inhabitants built little stalls by the sides of their houses, in which they kept their cattle at night. But these domestic animals were not descendants of the wild animals that roamed the forests of Europe. Like the plants, they are immigrants from the south-east. Our best authorities consider they were brought into Europe by the invading Neolithic tribes.