 Hilchot Nikkur (the excision of fatty tissue known as "suet" from the slaughtered animal) - by Rabbi Yehuda Sa'adi
Insomuch that I have seen in this, our orphaned generation, all of us groping like blind men to find the suet and its [appointed] places, and its [required] removal by excision, [not knowing] which of these [places] are to be judged strictly, and which of them are to be judged leniently; as also the [required] removal of the sinew [of the two hind legs], and the membranes, as also the "threads" (i.e.blood vessels and nerves) which are forbidden under the category of "suet," my heart has, [therefore], taken it upon itself to write what I have known about them, perchance those seeing my writing will give answer and show me the way of truth, and cause me to understand where I may have erred.All of the exponents of our laws whom I have known agree to [this] one opinion, that there are three fatty tissues (suet) which, [by eating], men would become liable to extirpation, and they are that which men offer to God [upon the altar].