Thomas Kirkup, A history of socialism, 4th ed… (1909)
“ The capitalist appropriates the product of labour because it contains surplus value. It is the part of the product that embodies surplus value and represents a clear gain which attracts him. Surplus value is the beginning, middle, and end of capitalism. It moves it alike in its origin and progress, decline and fall. It is the keynote of a great process of historic evolution continued for centuries; the secret of a vast development, which becomes more and more open as time goes on. And capitalism grows sick of the sustenance which formerly nourished it. ”
