These are apple carvings. They are preserved either in alcohol or silicone oil as per museum standards. They are permanent.
As a fresh carving they are quite amazing - apple flesh is the best medium for depicting human skin by a mile. Over time they loose their life like appearance and take on a cadaverous quality.
To me, they are like a museum specimen of a life lived trapped in
a jar / reality.
My favourite artists are people like Van Gogh, Munch, Lucian Freud, and Francis Bacon.The intensity and depth of their work is extraordinary - approaching madness.