I first came across it when it was cited (in a slightly abridged form) in Sir Richard Gregory’s Discovery; Or the Spirit and Service of Science in 1916 (Gregory, 1916: 18).
The letter is one of the many examples of Wallace revealing his genuinely never-ending passion for nature and its confusing, fascinating and beautiful variety:
My dear Young Friends:
Thank you much for your very kind greetings. I am much pleased that so many of you are readers of my books. The wonders of nature have been the delight and solace of my life. From the day when I first saw a bee-orchis (Ophrys apifera) in ignorant astonishment, to my first view of the grand forests of the Amazon; thence to the Malay Archipelago, where every fresh island with its marvellous novelties and beauties was an additional delight–nature has afforded me an ever-increasing rapture, and the attempt to solve some of her myriad problems an ever-growing sense of mystery and awe. And now, in my wild garden and greenhouse, the endless diversities of plant life renew my enjoyments; and the ever-changing pageants of the seasons impress me more than ever in my earlier days.
I sincerely wish you all some of the delight in the mere contemplation of nature’s mysteries and beauties which I have enjoyed, and still enjoy.
Yours very truly, Alfred R. Wallace.