I prepared this for last Thursday and then things happened and I never got around to posting it. (I was reminded of this when I started to prepare tomorrow's.) So here it is, a little delayed.
The last few pages have been discussing the kashrut status of various
uncommon cases of slaughter. A mishna on today's daf teaches: if a man
slaughtered an animal and found in its womb a viable fetus, if it is
alive he must slaughter it even though this violates the law of not
slaughtering a mother together with her young. This is the view of
Rabbi Meir. However, the sages disagree, saying he can slaughter it
without any complications. A footnote in the Soncino edition explains
that this is because it is still part of the mother, not having been born.
After birth slaughtering the offspring with the mother would be forbidden.
(74a)
The rabbis here are arguing that a fetus is part of the mother,
not a separate entity, until it is born; this is consistent with
Jewish law on abortion as I understand it. Rabbi Meir seems to be
arguing that the animal fetus is a separate entity; I have no idea
what his position on abortion is.