“Collecting butterflies was one of those hobbies of my early youth that, though it lasted only a little, nonetheless— with all the force of passion— took possession of me and left in my memory a deep, fresh impression that remains to this day. Since childhood I loved natural history; the book in Russian (whose title I don’t remember) with colorful pictures of animals, birds, and fish that fell into my hands while I was still in gymnasium—I studied it from cover to cover with reverence and even learned it by heart. And when I noticed that the book didn’t contain what, at first glance, my curious child’s attention had noticed, I myself tried to describe the little creatures, birds, and fish I had gotten to know…”