What's Bred in the Bone by Grant Allen

Hour after hour the unhappy man lay still as death on his bed and reasoned in vain with his accusing conscience. To be sure, he said to himself, no man was bound by the law of England to name his heir. It is for the eldest son himself to come forward and make his claim. If Guy and Cyril could prove their title to the Tilgate estates when he himself was dead, that was their private business. He wasn't bound to do anything special to make the way easy for them beforehand.

But still, when he saw them, his heart arose and smote him. His very class prejudices fought hard on their behalf. These men were gentlemen, the eldest sons of a Kelmscott of Tilgate -- true Kelmscotts to the core -- handsome, courtly, erect of bearing. Guy was the very image of the Kelmscott of Tilgate Park who bled for King Charles at Marston Moor; Cyril had the exact mien of Sir Rupert Kelmscott, Knight of Chetwood, the ablest of their race, whose portrait, by Kneller, hung in the great hall between his father; the Admiral, and his uncle, Sir Frederick. They had all the qualities the Colonel himself associated with the Kelmscott name. They were strong, brave, vigorous, able to hold their own against all comers. To leave them out in the cold was not only wrong -- it was also, he felt in his heart of hearts, a treason to his order.