Damn, I just bought the book.
Maybe my paranoia is setting in, but the pellet was silver and very shiny. Anytime I've found a shot pellet before, it has been black, not silver Is it possible that this pellet was a plant ? No no, of course not ! Any bird shooters out there who can tell me ?
Silver shot, well this is what you would use when shooting were-mallard. Nasty buggers, but good flavour.
In some areas of the world they are replacing lead shot with other types of metal as the lead tends to wind up in the local wild life and is not good for them. Also, those of use that have had the joy of producing their own shot gun cartridges will have seen that the fresh lead pellets are quite silvery (they haven't tarnished yet in other words). Lead is very soft, you could tell if it is lead by biting it or scratching it with a knife. I doubt that it would be planted, but you never know with these tricky London types.
Could the shortness of the letter have anything to doe with his illness do you think?