He became the first director of the Royal Belgian Institute of Natural Sciences in 1846. On this occasion he donated 2474 birds from his own collection to the museum. In 1860, during the construction of new fortifications around Antwerp he became involved in paleontology. The fossils found were mainly from whales. He also obtained the skeletons from a bowhead whale (Balaena mysticetus) and a young Blue Whale (Balaenoptera musculus), which are still on display in the museum. In 1860 the skeleton of a mammoth was found near Lier and was brought to the museum (on display since 1869). At that time the only other skeleton of a mammoth was on display in the museum of Saint Petersburg (Russia).