Water blue and methyl blue are the constituents of aniline blue WS, a dye which traditionally has been a variable mixture of the two, although Gurr uses the name aniline blue instead of water blue for it. Any of the three will generally be found suitable for staining collagen in Masson's trichrome and Mallory's method for connective tissue.
R. D. Lillie.
Conn's Biological Stains
Williams & Wilkins, Baltimore, MD., U.S.A.