Revision of his older drawings demanded much of Audubon's attention during these years. On February 10, 1828, he began the Whiteheaded Eagle (No. 7, Plate xxxi), the original of which had been procured on the Mississippi, where the bird was represented as dining on a wild goose; now, he said, "I shall make it breakfast on a catfish, the drawing of which is also with me, with the marks of the talons of another eagle, which I disturbed on the banks of the same river, driving him from his prey." On the 16th of that month he was engaged with this drawing from seven in the morning until half after four, stopping only to take the glass of milk which his landlady would bring to him. This plate was engraved in the following April, and on May 1, 1828, a first proof was sent to the Marquis of Landsdowne, president of the Zoölogical Society, as a mark of appreciation by its author, who had become a member of that body in the preceding winter. A striking characteristic of Audubon's work was its diversity, produced not only by attractive embellishments of many kinds, but by the moving force and action with which he ever sought to vitalize his subjects. It is therefore not surprising that he was nettled by an incident like this: February 28. To-day I called by appointment on the Earl of Kinnoul, a small man, with a face like the caricature of an owl; he said he had sent for me to tell me all my birds _were alike_, and he considered my work a swindle. He may really think this; his knowledge is probably small; but it is not the custom to send for a gentleman to abuse him in one's house. I heard his words, bowed, and without speaking, left the rudest man I have met in this land. Audubon had not yet visited the great university towns of England, the support of which he knew would be a valuable asset, and on March 3, 1828, he set out by stage for Cambridge. His driver, he remarked, "held confidances with every grog-shop between London and Cambridge, and his purple face gave powerful evidences that malt liquor [was] more enticing to him than water." His reception at Cambridge was hearty; he was entertained by Professors Sedgwick, Whewell, and Henslow, dined repeatedly "in Hall" with the dons, and received the subscription of the librarian of the University. It is interesting to recall that young Charles Darwin, "the man who walks with Henslow," as some of the dons called him, was then an undergraduate at King's College, and that thirty-one years were to pass before modern biology was born in 1859, the year of the appearance of the epoch-making _Origin of Species_.