Beitza 27a.
1-Our Gemara offers two options on how to define an expert’s opinion after he inspects a Bechor and ascertains that a blemish he spotted is indeed permanent:
A- His ruling ‘creates’ the היתר. Meaning that his opinion renders the animal a Ba’al Mum and thus permissible to be shechted and consumed.
B- His opinion just reveals to us what the status of this animal is.
The practical difference is whether one may inspect such an animal on YomTov. If the expert is actually creating the היתר (option a above) the Gemora says is prohibited since it is like מתקן מנא.
2- The Gemara tries to understand how a Tana of a previous generation agrees with a much younger Tana of a later generation.
3- We mentioned the Sicha of the Rebbe in regards to Reb Leib Sara’s. The Rebbe said that in the famous book ‘Reziel Hamalach’ (which he mentioned is a segula to have one in a Jewish home) which was printed way before Reb Leib Sora’s times (and was in manuscript form hundreds of years before that) there is a תפילה ‘for the opening of the heart of Leib Ben Sora!
See here. https://sichoskodesh.com/pdf/5730v2.pdf
Page 58.
More on this Sicha ahead.
4- We learned the text of the Shulchan Aruch concerning as to what type of מום is considered permanent. We find a difference between Ashkenazim and Sfardim.
שו”ע יו”ד שט ב. רמ”א
http://beta.hebrewbooks.org/tursa.aspx?a=yd
5- From there we moved to a case where one shechted a Bechor and only then called the expert (after the fact) and the expert confirms that it indeed had a blemish before the shchita.
Reb Meir prohibits the animal and it must be buried. As mentioned in 1-A above the ruling creates the היתר and needs to be done before the שחיטה.
See here: שו”ע שי א.
6- We discussed the case of a Sefer Torah that was written on parchment made from such an animal.
We mentioned the Netziv in his book משיב דבר take on this question.
נצי”ב.
In passing we mentioned the ongoing argument as to why the famous Yeshiva in Volozhin was closed by the Russian authorities in 1893. (see also R Chaim of Volozhin)
7- We concluded with the rest of the fascinating Sicha where the Rebbe suggested that Reb Leib Sora’s and the Shepole Zeida were the same person.
Leib Sora and Shpole Zeide
Seems the Rebbe received a mountain of mail from the many descendents of both there greats.
At the next farbrengen the Rebbe added that until he hears from a reliable person or testimony that there are two מציבות showing that they were indeed two separate people……. It possible to say that they were the same person.
He ended off saying and שלום על ישראל…….!
https://sichoskodesh.com/pdf/5730v2.pdf
96-97
http://toladot.blogspot.com/2010/08/blog-post_25.html