His Amazon and Far Eastern trips were supported by the sale of specimens he collected and, after he lost most of the considerable money he made from those sales in unsuccessful investments, he had to support himself mostly from the publications he produced.
Perjalanannya ke Amazon dan Timur Jauh dibiayai dari penjualan spesimen-spesimen yang berhasil ia kumpulkan dan, setelah kehilangan sebagian besar uangnya dari semua hasil penjualan tersebut akibat berbagai kegagalan investasi, ia seringkali harus membiayai dirinya sendiri dari publikasi-publikasi yang ia hasilkan.