The experiments in palingenesia (regeneration) are without question the most mysterious carried out by the Prince of Sansevero. According to contemporary sources, he was capable of reproducing plants, insects and small animals from their ashes. Di Sangro’s reserve about the methods of the activities, however, was almost absolute.
A record of one of these incredible experiments is provided by Giangiuseppe Origlia, who speaks of a veritable “resurrection of river crabs, which after being burned to ashes produce a large number of insects, and thus from the second daily feed with fresh ox blood, used in a particular way, brand new ones are born”. The astronomer Joseph Jérôme de Lalande, who met the Prince and visited his palace, tells in his memoirs of a journey of a “natural palingenesia of plants and animals, especially with fennel ash, which, according to him, reproduced the plant”.
Indicative of the greatest reserve with which di Sangro kept his secret is the concluding passage of the anonymous Short note on what can be seen in the house of the Prince of Sansevero, where, hinting at the “fine experiments made above all in palingenesia”, it states that to be able to observe them, “you need a certain familiarity with the Prince”.