In the first chapter, Kino pleads the doctor to help coyotito heal from his scorpian sting, but the doctor truns him down because he Kino has no money. Later, when Kino acquires the pearl, the doctor hears of this and says "He is a client of mine." This is ironic because at first the doctor refused him because he had no money, but when he acquired the pearl, the doctor immediately tries to help him.
