On the occasion of his 80th birthday celebration, he was presented with a two volume work, entitled Was wir Ernst Haeckel verdanken (What We Owe to Ernst Haeckel), edited at the request of the German Monistenbund by Heinrich Schmidt of Jena.
Pada peringatan ulang tahun ke-80, ia diberi dua jilid karya berjudul Was wir Ernst Haeckel verdanken (What We Owe to Ernst Haeckel), disunting atas permintaan German Monistenbund oleh Heinrich Schmidt dari Jena.