At a later date the verse portions were separated from the prose and we thus obtain two forms of the Yajur-Veda, the older or mixed edition being called the Black Yajur-Veda, and the unmixed being called the White Yajur-Veda.

– William Spence Urquhart: ‘Pantheism and the value of life, with Special Reference to Indian Philosophy’, The Epworth Press, 1919