The culture of the potato and of food-yielding plants, and the more recent improvements made in agriculture generally, have increased tenfold the productive powers of the human race for the creation of the means of subsistence.

• 然而现在一个欧洲就有两亿人在生活，马纷薯与其他粮食作物种植的推进与近来农业上一般的改进，使人类供应食料的生产力提高了十倍。