An “incorrupt body” is not an accidental preservation such as a person falling into ice in a glacier, nor a deliberate attempt at preservation through embalming or mummification. In both those instances, when found, a corpse may be typically discolored, distorted, have a bad odor, and decay rapidly after examination.
An "incorruptible" does not fit either the accidental or deliberate preservation categories. This type of preserved body remains free from decomposition regardless of manner of burial, temperature, or moisture content. They have been found starting after the death of Christ, and to this day the causes of preservation of these corpses still cannot be resolved by science.
There are more than 250 incorrupt bodies of Catholic Saints. They include such notable holy people as St. Teresa of Avila who died in 1320, Saint Catherine of Sienna who died in 1380, Saint Francis Xavier who died in 1552, Saint John Vianney (the Cure’ of Ars) who died in 1859, St. Catherine Laboure who died in 1876, etc.
