The notion of racial blood in Gobineau's Essai sur l'inégalité des races humaines is not deployed in a strictly physiological manner. Gobineau refers to blood in a number of passages designating a spiritual and historical substance accounting for the unity of a people. This use of the term cannot be discredited by a chemical or genetic analysis of the material blood because Gobineau is not engaged in a classification of physical body types but rather a historical explanation of civilizations’ progress and degeneration. The blood refers to more than a mere biological trait. And the term is deployed in an attempt to comprehend one's physical, psychical, social, political, and, above all, historical ways of being.