He built up a collection of living animals whose skeletons and other organs he prepared as anatomical specimens, eventually amassing nearly 14,000 preparations demonstrating the anatomy of humans and other vertebrates, included 3,000+ animals.
Ia mulai mengkoleksi hewan yang berkerangka dan organ-organ lainnya dia siapkan sebagai spesimen anatomi, akhirnya dia mengumpulkan hampir 14.000 persiapan pendemonstrasian anatomi manusia dan vertebrata lainnya.