Feather These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so the barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular "calamus" (or quill) which inserts into a follicle in the skin. The basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base (proximal umbilicus) and a small opening on the side (distal umbilicus). Hatchling birds of some
Calamus (poems) sequence as written celebrates many aspects of "comradeship" or "adhesive love," Whitman's term, borrowed from phrenology to describe male same-sex attraction. This attraction is presented in its political, spiritual, metaphysical, and personal phases—Whitman offering it as the backbone of future nations, the root of religious sentiments, the solution to the big questions of life, and as a source of personal anguish and joy. The 1860 edition contains three poems that Whitman would later edit out of the sequence, including the very personal Calamus 8, "Long I thought that knowledge alone would suffice me," and Calamus 9, "Hours continuing long, sore