Bava Metzia 8: Taking Ownership from Someone or No One

Using a formal act of acquisition to take possession of an object on behalf of someone else - works! (Pending discussion whether it really does, and how that connects to the 2 who have taken hold of the talit in the first mishnah of Bava Metzia. Also, the formal kinyan of taking hold of an animal's bridle - which is complicated when that animal had been the property of a convert who didn't have heirs. Thus, the real difference between taking possession of something that had a previous owner, as compared to found property.