Sherlock Holmes - Deductions

‘I might suggest that you have gone about in fear of some personal attack within the last twelvemonth.’
“The laugh faded from his lips, and he stared at me in great surprise.
“‘Well, that’s true enough,’ said he. ‘You know, Victor,’ turning to his son, ‘when we broke up that poaching gang they swore to knife us, and Sir Edward Holly has actually been attacked. I’ve always been on my guard since then, though I have no idea how you know it.’
“‘You have a very handsome stick,’ I answered. ‘By the inscription I observed “‘You have a very handsome stick,’ I Sherlock Holmes)answered. ‘By the inscription I observed that you had not had it more than a year. But you have taken some pains to bore the head of it and pour melted lead into the hole so as to make it a formidable weapon. I argued that you would not take such precautions unless you had some danger to fear.’
“‘Anything else?’ he asked, smiling.
“‘You have boxed a good deal in your youth.’
“‘Right again. How did you know it? Is my nose knocked a little out of the straight?’
“‘No,’ said I. ‘It is your ears. They have the peculiar flattening and thickening which marks the boxing man.’
“‘Anything else?’
“‘You have done a good deal of digging by your callosities.’
“‘Made all my money at the gold fields.’
“‘You have been in New Zealand.’
“‘Right again.’
“‘You have visited Japan.’
“‘Quite true.’
“‘And you have been most intimately associated with someone whose initials were J. A., and whom you afterwards were eager to entirely forget.’
‘When you bared your arm to draw that fish into the boat I saw that J. A. had been tattooed in the bend of the elbow. The letters were still legible, but it was perfectly clear from their blurred appearance, and from the staining of the skin round them, that efforts had been made to obliterate them. It was obvious, then, that those initials had once been very familiar to you, and that you had afterwards wished to forget them.’

He sat down opposite to me, drew the lamp to the edge of the table, and handed me a short note scribbled, as you see, upon a single sheet of 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.’
“I daresay my face looked as bewildered as yours did just now when first I read this message. Then I reread it very carefully. It was evidently as I had thought, and some secret meaning must lie buried in this strange combination of words. Or could it be that there was a prearranged significance to such phrases as ‘fly-paper’ and ‘hen-pheasant’? Such a meaning would be arbitrary and could not be deduced in any way. And yet I was loath to believe that this was the case, and the presence of the word Hudson seemed to show that the subject of the message was as I had guessed, and that it was from Beddoes rather than the sailor. I tried it backward, but the combination ‘life pheasant’s hen’ was not encouraging. Then I tried alternate words, but neither ‘the of for’ nor ‘supply game London’ promised to throw any light upon it.
“And then in an instant the key of the riddle was in my hands, and I saw that every third word, beginning with the first, would give a message which might well drive old Trevor to despair.
“It was short and terse, the warning, as I now read it to my companion:
“‘The game is up. Hudson has told all. Fly for your life.’