Some interesting comments in that thread. I think they kept focusing on an incorrect idea though, which is that the knife was something hand picked by Lord Greystoke. As I recall, Lord and Lady Greystoke are marooned on the African coast by mutineers, and are supplied with equipment from the ship's stores. So, they probably had some of their personal belongings, such as their clothing and the children's books that Tarzan later teaches himself to read with, but I would think that any survival equipment, such as the pistols, rifles, axes, knives, etc. that they had were not personal items chosen by Tarzan's father. It's been a long time since I've read the book though, so I might be very wrong.