A conditioned stimulus is a stimulus that arouses the exact response by the individual as aroused by an unconditioned stimulus. The response that the individual shows are the result of continuous exposure or repeated conditioning. Because of this reason, the individual's natural response accompanies the stimulus and occurs with the occurring of the stimulus.
In the given excerpt, the sight of the house is the conditional stimulus because of the anxious feeling that the boy was suffering. The experience of getting bitten by a dog at that house and the fear of it has formed an image in the mind of the child.
