The Adventure of the Gloria Scott Sherlock Holmes

"I have some papers here," said my friend Sherlock Holmes, as we sat one winter's night on either side of the fire, "which I really think, Watson, that it would be worth your while to glance over. These are the documents in the extraordinary case of the Gloria Scott, and this is the message which struck Justice of the Peace Trevor dead with horror when he read it."
He had picked from a drawer a little tarnished cylinder, and, undoing the tape, he handed me a short note scrawled upon a half-sheet of slate-gray paper.
"The supply of game for London is going steadily up," it ran. "Head-keeper Hudson, we believe, has been now told to receive all orders for fly-paper and for preservation of your hen-pheasant's life."
As I glanced up from reading this enigmatical message, I saw Holmes chuckling at the expression upon my face.
"You look a little bewildered," said he.
"I cannot see how such a message as this could inspire horror. It seems to me to be rather grotesque than otherwise."