Some sort of surgical tubing (?) that would be slid over the end of the shaft, behind the broadhead and poison somehow rolled up in it. At impact, the tubing would roll back and the poison would hit the blood stream and death was fairly quick?
I remember reading about it in early Bowhunter magazines.
String trackers! Good memories of those from the 80's! Looked like a mess of kite string all over the woods a couple times, lol.
