Collagen connective tissue narrowly refers to the three kinds of fibers it contains: collagen fibers, reticular fibers, elastic fibers, and collagen fibers (collagen fiber) is the most widely distributed and most abundant kind of fiber.

Weigert iron hematoxylin staining solution is a staining solution with strong staining power, mainly composed of hematoxylin and ferric chloride, mixed before clinical use, mostly used for connective tissue staining, such as masson trichrome staining, Van Gieson staining and so on.