(Mishnah): One who finds fruits on the road and he took them to eat and later decided to store them away; he may not store them unless he first tithes. If originally, he took them merely to prevent them from being wasted (but he had no intent to acquire them) he is exempt from tithing.

Anything that a person may not sell as Demai, he should not send it to his friend as Demai.

R. Yosi permits it when it is definite, as long as he informs them that it's definite Tevel.

(Gemara) (Baraisa): One may not pass by food (in the street without picking it up).

(R. Yaakov bar Zavdi citing R. Avahu): That was originally, but nowadays, it is permitted, since the food left in the street might have been harnessed for witchcraft.

(Mishnah in Bava Kama): If someone moved a compost heap in a public domain and someone else collided with it and was damaged, the first person is liable to pay the damages.

(Baraisa): And there was a prohibition of theft on the heap (so when this person moved it, he acquired it).

Question (Kahana): He only acquired it if that was his intention. But in terms of damages, his intention makes no difference - he is still liable. So how could the Mishnah here say that if he doesn't want to acquire the fruit, he can leave it without tithing?

Answer (R. Avin): There, the pasuk states (Shemos 21:34), "The owner of the pit shall pay" - the one who damaged must pay; here the pasuk states (Devarim 14:22), "You shall surely tithe" - you must only tithe your own produce, but not another's produce.

Anything that a person may not sell as Demai, should not be sent to someone as Demai. A small quantity that may not be sold as Demai should not be sent as Demai. A large quantity that a person may sell as Demai may also be sent to someone as Demai.

R. Yosi permits it with definite Tevel, whether a small or large quantity and prohibits Demai in a small quantity.

(R. Abahu citing R. Yochanan): Why did Chazal exempt a large quantity from Demai? Since the seller doesn't earn much when selling a large quantity, they exempted him from separating. This explanation can be seen in a Mishnah in the 2nd Perek - R. Yosi says that fig baskets, grape baskets and boxes of vegetables - as long as he sells them through estimation (rather than size), they are exempt (as he doesn't earn much through estimation).

Tosefta (R. Shimon ben Gamliel): R. Yosi bei Rebbi sent me an Esrog with a message that it had come from Kisarin. I learned 3 things from this - that's it's definite Tevel, that it's susceptible to Tumah (as it must have become wet) and that R. Yosi had no other Esrog other than this with which to separate Maaseros for it...

'It's definite Tevel' - as the produce of Kisarin is definite Tevel; 'it's susceptible to Tumah' - because they sprinkle water on it; 'that R. Yosi had no other Esrog...' - as if he would have had another, he would have separated Maaseros for it.

Question: Why didn't R. Yosi separate a part of the Esrog for the Esrog itself (before he sent it)?

Answer: He was concerned for the teaching of Bar Kapara, who said that it is not accepted practice to send incomplete items as gifts.

Question: (How do you know that he only had one Esrog?) Doesn't our Mishnah teach that R. Yosi permits sending definite Tevel, as long as he informs them what it is?

Answer: Rabban Shimon came to teach that even though R. Yosi disagrees with the Rabbanan (and permits sending definite Tevel; but if he could tithe it) he would not act on his own ruling.

Question (R. Zeira to R. Yasa): Why was the Esrog Tevel - isn't the produce of Kisarin exempt?

Answer: It was Rebbi who permitted Kisarin and Rabban Shimon ben Gamliel preceded him.