Though collagen extracted from animal bones and tissue can be converted into gelatin, we shouldn't ascribe any particular significance to a refrigerator case, full of desserts like this ($2), near the entrance to a butcher shop. Almost certainly the gelatina Mexicana at this carniceria is made using packaged mixes, not from scratch. I'd expected the jiggly grape, lime, orange, and strawberry slabs to be suspended in some sort of custard, but lo and behold, the creamy base of that pale yellow matrix was gelatinized, too.
Don Francisco Carniceria
4805 Fifth Ave. (48th-49th Sts.), Sunset Park, Brooklyn