In "The Surgeon's Mate" by Patrick O'Brian, the protagonist's deep affection for his country provides him with a sense of protection and warmth, akin to a greatcoat. This metaphor reflects how patriotism can serve as a shield against adversity, emphasizing the strength and resilience that comes from national pride.

The quote underscores the idea that love for one's homeland can be both comforting and empowering, suggesting that such feelings can help individuals navigate challenges. This connection to their country becomes a source of strength, influencing their actions and decisions throughout the narrative.