Farming and Gardening for Health or Disease

One of the developments which marks off the modern world is the growth of population. The figures are startling. There were about nine hundred million persons living during the eighteenth century, but over two thousand million at the beginning of the twentieth; in a century and a half world population, therefore, more than doubled. The principal increases took place in Europe.

The first effect of this is obvious -- there were many more mouths to feed. Had no other changes accompanied this rise in population, we can guess what might have happened. The density of the peoples in rural Europe might have rivalled that in peasant China, and European agriculture would either have had to evolve methods of intensive cultivation similar to those of the Chinese or the additional population could not have survived.