I'm reading the preface to Old Indian Legends by Zitkala-Ša, originally published in 1901. My mother tongue is not English, and I am having some trouble understanding - in detail - what she actually means or refers to in the final sentence of the quoted text below. I include the whole paragraph for context:
The old legends of America belong quite as much to the blue-eyed little patriot as to the black-haired aborigine. And when they are grown tall like the wise grown-ups may they not lack interest in a further study of Indian folklore, a study, which so strongly suggests our near kinship with the rest of humanity and points a steady finger toward the great brotherhood of mankind, and by which one is so forcibly impressed with the possible earnestness of life as seen through the teepee door!