The cow that nourished Ymir with four streams of milk was called Audhumla. (Scandinavian mythology.) (See Audhumla.)
“The system of impropriations grew so rapidly that, in the course of three centuries, more than a third part of all the benefices in England became such, and those the richest, for the whiter the cow, the surer was it to go to the alter.” —Blant: Reformation in England, p. 63.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894