The Wealth of Nations by Part 4 Chapter 7 Page 94

In all European colonies the culture of the sugar-cane is carried on by negro slaves. The constitution of those who have been born in the temperate climate of Europe could not, it is supposed, support the labour of digging the ground under the burning sun of the West Indies; and the culture of the sugarcane, as it is managed at present, is all hand labour, though, in the opinion of many, the drill plough might be introduced into it with great advantage.

But, as the profit and success of the cultivation which is carried on by means of cattle, depend very much upon the good management of those cattle, so the profit and success of that which is carried on by slaves must depend equally upon the good management of those slaves; and in the good management of their slaves the French planters, I think it is generally allowed,