Blemishing the Blemished
An animal must be without a physical blemish in order to qualify as a sacrifice. It is forbidden to inflict a blemish upon an animal consecrated as a sacrifice since this renders it unfit for the altar.
This prohibition raises an interesting problem in regard to one such consecrated animal the male firstborn of cows and sheep that must be given to a kohen who will offer it as a sacrifice and eat its meat. If such an animal suffers the blemish of a serious condition that requires the surgery of bloodletting to save it, is it permissible to perform this surgery even though it means inflicting it with a disqualifying blemish? Or must caution be taken to limit such surgery to a place that will heal and not cause a blemish?
The crux of the question is whether there is a prohibition against inflicting a blemish upon an animal that is already blemished. The answer depends on the interpretation of two parts of the same passage dealing with this prohibition.
"Unblemished shall it be to be acceptable, no blemish whatsoever shall be in it."
Rabbi Meir saw in the prohibition against causing a blemish to a sacrificial animal that is implied in this passage a sweeping ban on doing so even if a blemish already exists. The word kol used to insist on "no blemish whatsoever" is all-inclusive.
The other Sages, however, point to the earlier part of that passage which limits the prohibition to an animal that is still unblemished, allowing us to conclude that if it already has a blemish, such as in the bloodletting case cited above, there is no ban on inflicting an additional blemish.
Neither of the two parties to this debate is oblivious to the source cited by the other. Rabbi Meir, however, interprets the exclusion cited by the other Sages as applying only to a blemished sacrificial animal that has been redeemed from the Sanctuary, allowing for another blemish to be inflicted on it. The other Sages, in turn, interpret the all-inclusive word kol as a ban on indirectly causing a blemish such as placing some sweet foodstuff on the animals ear so as to invite a dog to bite it off and wound the animal.Menachot
When Adding Subtracts
For certain sins there is a sliding scale for the nature of the atonement depending upon the economic situation of the sinner. One who can afford neither animal nor bird as a sacrifice is given the opportunity to atone for his sin by bringing a mincha flour offering.
This mincha differs from those brought as voluntary offerings in that no oil or incense may be added to it. What happens, however, if the kohen handling this offering put oil or incense on it is the offering disqualified? It all depends on how we understand the passage containing this prohibition.
"He shall put no oil upon it," says the Torah, "nor shall he put any incense upon it, for it is a sin offering." (Vayikra 5:11)
The stress on the word "it" indicates that it qualifies as an atonement mincha only if he follows the Torahs instructions of not adding these forbidden ingredients. The use of the term "sin-offering" after mentioning the addition of oil and incense sends an opposite signal that even if the kohen made the forbidden addition the mincha is still valid.
The gemaras resolution is that there is a difference between adding oil and adding incense. Since oil that has been absorbed by the flour cannot be separated from it, the mincha becomes disqualified. In the case of incense, however, it is possible to remove the incense from the surface of the mincha, so it does not become disqualified by merely adding that separable ingredient.