The Wealth of Nations by Part 4 Chapter 5 Page 61

it is of all commodities the least liable to be engrossed or monopolized by the force of a few large capitals, which buy up the greater part of it. Not only its value far exceeds what the capitals of a few private men are capable of purchasing, but, supposing they were capable of purchasing it, the manner in which it is produced renders this purchase practicable. As in every civilised country it is the commodity of which the annual consumption is the greatest, so a greater quantity of industry is annually employed in producing corn than in producing any other commodity. When it first comes from the ground, too, it is necessarily divided among a greater number of owners than any other commodity; and these owners can never be collected into one place like a number of independent manufacturers, but are necessarily scattered through all the different corners of the country.