During this period, despite having lost almost all of the notes from his South American expedition, he wrote six academic papers (which included "On the Monkeys of the Amazon") and two books; Palm Trees of the Amazon and Their Uses and Travels on the Amazon.
Während dieser Zeit und obwohl fast sämtliche Notizen über seine Südamerikaexpedition verlorengegangen waren, veröffentlichte er sechs Artikel (darunter On the Monkeys of the Amazon) und die beiden Bücher Palm Trees of the Amazon and Their Uses (Palmen aus dem Amazonas und ihre Verwendung) und Travels on the Amazon (Reisen im Amazonas).