The Wealth of Nations by Part 2 Chapter 1 Page 7

A flock of sheep or a herd of cattle that, in a breeding country, is bought in, neither for labour, nor for sale, but in order to make a profit by their wool, by their milk, and by their increase, is a fixed capital. The profit is made by keeping them. Their maintenance is a circulating capital. The profit is made by parting with it; and it comes back with both its own profit and the profit upon the whole price of the cattle, in the price of the wool, the milk, and the increase. The whole value of the seed, too, is properly a fixed capital. Though it goes backwards and forwards between the ground and the granary, it never changes masters, and therefore does not properly circulate.

The farmer makes his profit, not by its sale, but by its increase.

The general stock of any country or