In 1825 the government of the Dutch-Indies provided him with two assistants: apothecary and mineralogist Heinrich Bürger (his later successor) and the painter Carl Hubert de Villeneuve.
En 1825 a Compañía das Indias Orientais subministroulle a von Siebold dous asistentes: o farmacéutico e mineraloxista Heinrich Bürger (o seu último sucesor) e o pintor Carl Hubert de Villeneuve.