Cohn, Jacob. The Royal Table - VWC: Faculty/Staff Web

72 THE ROYAL TABLE
have visibly pierced the outer side of the gizzard, in which
instance the fowl is trefah regardless of the absence of a
clot. 60
In all of the above laws involving perforations the
following limitation applies: if the hole is stopped up with
clean fat, it is discounted; but unclean fat (cheleb) cannot
plug up a perforation. 61 In the next chapter the nature of
these two kinds of fat will be dealt with at greater length.
60 Yoreh Deah, ibid, and Shack ad loc. subset 4, where different
opinions are discussed.
61 See Tosaphoth Hullin 49a