Introduction to Oktzim
The final tractate of Seder Toharot and indeed of the entire mishnah deals with things that are “stems” to food. The question is when is something considered to be attached to food such that if one part becomes impure the whole is impure and when are they independent?
This tractate does not really contain a lot of new information. Rather, most of it has been taught elsewhere. At times these mishnayot add information to the earlier ones and at times they are only repetitive. I think the best reason why these halakhot are found in two places is that the Mishnah’s editors thought that these halakhot could belong in two places.
There is some evidence that already in Talmudic times Tractate Oktzim wasn’t all that well learned. For instance there is a story in the Bavli (Horayot 13b) that some students wanted to belittle Rabban Shimon ben Gamaliel so they asked him to teach Oktzim, which he didn’t know. So consider yourselves lucky to be learning this Tractateyou can learn material that even the greatest of rabbis didn’t get to learn all that well.
Good luck in learning the tractate. It’s our last one, so I hope you treasure it.