Who is Whitey Whiteside from Jim the Boy: A Novel and what is their importance?

Whitey Whiteside is a traveling salesman, who works for Governor Feed. He attempts to get Cissy to marry him, but she rejects him. Whitey seems genuinely fond of Jim and gives him a baseball for his birthday, but it seems possible that Whitey may have been trying to earn Cissy's approval. After he is fired from his job, Whitey tells Jim that he will be moving on in search of another job.