In the excerpt from "The Commodore" by Patrick O'Brian, the author discusses the psychological impact of a mariner receiving a dose of a substance, emphasizing the importance of perception. The mariner feels a sense of assurance knowing he has been treated, and this belief amplifies his confidence and well-being. The mere awareness of being dosed becomes a powerful mental boost, reinforcing the idea that expectation can significantly influence one's health and state of mind.

Furthermore, the aroma of the drug plays a crucial role in enhancing the experience. Even with a small quantity, the scent reassures him of its effectiveness, demonstrating how deeply the human mind is intertwined with sensory experiences. This connection suggests that the mental aspect of treatment can be as vital as the physical substance itself, highlighting the significance of belief in the healing process.