The mishna distinguishes between noticeable changes and those that aren’t noticeable. The robber acquires only through a noticeable change. There is a debate in the mishna regarding slaves – whether they are treated like land in which the robber does not acquire the slave or is it like movable property and it is acquired by the robber. Rav paskens like Rabbi Meir that the slaves are like land. This psak is questionedby the gemara from a number of different directions. Can usage of a stolen slave who isn’t working be compared to usage of an uninhabited house – where one who uses another’s house since he isn’t causing a loss for the owner, he does not need to pay? What if one uses another’s boat without permission, what does he need to pay the owner? The mishna distunguishes between coins that are ruined physically and those that are removed from currency. The rabbis debate what exactly is the case of removed from currency – cannot be used in that country but can be used in another or cannot be used anywhere? The gemara gets into a case of one who takes a loan valued at an old currency and when he goes to pay back the loan, the currency is no longer in use. Rav and Shmuel debate the case and Shmuel’s opinion is questioned especially in light of how Rav Nachman understand’s Shmuel’s psak.