Originally posted by Yarcofin
Is there any physical explainations for it? Has the church ever allowed any of the bodies to be scientifically tested?
For the most part it cannot be explained, though there are cases outside of the Church where bodies have mummified in favorable conditions.
Generally it is considered a sign and/or confirmation of sanctity. Though lack of incorruptibility does not mean anything, generally a truly incorrupt
body years after burial in conditions where it should have decayed is would be an additional confirmation for sainthood. These saints bodies have also
been known to emit a smell of roses, as oppossed to rotting.
Not all incorruptibles have been exhumed for display. Some were discovered and then reburied. I believe Jacinta of Fatima was one. It's a fascinating
phenomenon.
It should be noted that St. Bernadette is probably one of the finest examples of incorruptibility, and also noted that once put on display there was
concern of deterioration due to exposure. I believe she was coated with something (wax?) to maintain what was discovered years after her death.