“May I ask whether the black drop, which in our social register makes the whole man black, has manifested itself, and if so, how?" Mr. Seaton explained. He had not noticed or suspected it until the neighbors began to talk. He was not certain then. The child was dark, but no darker than many a white child. He had supposed that his complexion might be due to Spanish or Italian or possibly American Indian strain, any one of which was an acceptable ingredient of the American melting pot. His hair was very curly, but not kinky, it had the texture of a white person’s hair. None of the physical stigmata of the Negroid except color were present, and he would not have believed the boy was colored without further knowledge of his origin. But the doubt was only less poignant than the verified fact.” (p. 21-22)
Chesnutt introduces one-drop rule. For more information on the “one-drop” law go to Chapter XXIX.