Genesis 30:39

And the flocks conceived before the rods
At them, and in sight of them; which had such influence upon them through thee force of imagination, and a divine power and providence so directing and succeeding this device, that they brought forth cattle ringstraked, speckled, and spotted;
such as Jacob was to have for his hire; and, though there was no doubt a more than ordinary concourse of divine Providence attending this affair; yet there have been many strange things brought about in a natural way by the strength of imagination, as may be observed in those marks which women are said to mark their children with, while with child of them; as also in conceiving and bearing such like unto them they have fancied, as the woman that bore a blackamoor, through often looking at the picture of one in her chamber; and an Ethiopian queen, who by the same means bore a white child, fair and beautiful, which she exposed, lest she should be thought an adulteress ^F18: and what comes nearer to the case here, Jerom reports ^F19 the like things done in Spain among horses and mares, by placing beautiful horses before mares at the time of leaping; and the Apis, or Egyptian ox, which had peculiar spots in it, was produced in like manner, so that there was always in succession one of the same form and colour, as Austin asserts ^F20; and it may be observed, what is affirmed by some writers ^F21, that sheep will change their colours according to the different waters they drink of at the time of their being covered; and that some rivers drank of will make white sheep black, and black white, and others red and yellow. But as Jacob was directed of God to take this method, this is sufficient to justify him, and upon his blessing and providence the success depended, whatever there may be in nature to bring about such an effect; and as it was to do himself justice, who had been greatly injured by Laban, it was equally as just and righteous a thing to take this course, as it was for the Israelites by a divine direction to borrow jewels of the Egyptians, whereby they were repaid for their hard service. (This was written over one hundred years before the laws of genetics were discovered. We know that the result was from God not of Jacob's schemes. Ed.)