The Triumph of Brahmanism, BAWS 3, pp. 275, 285–86
The deeds or misdeeds of this triumphant Brahmanism may be catalogued under seven heads. …(3) It converted the Varna into caste.
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As I said Manu’s ways are silent and subterranean and we cannot give the detailed and chronological history of this conversion of Varna into Caste. But fortunately there are landmarks which are clear enough to indicate how the change was brought about.
Before proceeding to describe how this change was brought about let me clear the confusion between Varna and Caste. This can best be done by noting the similarities and differences between the two. Varna and Caste are identical in their de jure connotation. Both connote status and occupation. Status and occupation are the two concepts which are implied both in the notion Varna as well as in the notion of Caste.
Varna and Caste however differ in one important particular. Varna is not hereditary either in status or occupation. On the other hand Caste implies a system in which status and occupation are hereditary and descend from father to son. When I say that Brahmanism converted Varna into Caste what I mean is that it made status and occupation hereditary.