Hemacolor staining of the threadlike structure isolated from the rat abdominal subcutaneous tissue. (a) Threadlike structure isolated from the Hemacolor-stained layer of the subcutaneous tissue. (b) Typical longitudinal image of a whole threadlike structure (marked as “b” in (a)). ((c) and (d)) Two major types of cells in the threadlike structure: large granular (arrows) or small round cells (arrowheads). Note that the cells in the node (c) and in the vessel (d) are aligned differently. (e) Toluidine blue staining of the large granular cells (arrows).