He seems to have been as willing to sacrifice himself for his master as any dog would have been.

Or else he counted on Brice's not having any evidence to hold him on.
"By the way, do you remember that conch, Davy, over at Roustabout Key?
Brice says he's a Secret Service man.

He and Brice used to fish together, off the keys, when they were boys.

Davy volunteered for the war.

And Brice made good use of him, over there, and got him into the Secret Service when they came back.