Heavy-metal stains, wool

Use Red dye for paper, also for wool and silk where brilliant fluorescent effects are desired and light-fastness is of secondary importance analytical reagent for certain heavy metals, biological stain. 

Early studies on the fine structure of specialty animal fibers involved differential staining using dyestuffs or heavy metals, and subsequent observations were made using light microscopy. By means of these techniques, vicuna fiber was shown to have a bilateral structure [318], and mohair fiber, predominantly ortho- with some paralike material [319] (see Sections 5.2.2 and 5.2.3). Bilateral structures are also observed when wool, cashmere, camel, and alpaca (but not mohair) are treated with sodium hydroxide and examined by means of polarized light [297]. 

Uses Dye for cellulose and silk fibers dye to stain wool, acetate and nylon fibers dye to print cellulose and silk fibers dye for leather, paper, and casein-formaldehyde plastics prod, of its heavy metal salts for use as pigments... 

---