MUCIN. 431 



wiss. Mik.j 1885, p. 518) : Stain sections first with haeina- 

 toxylin of Heidenhain, and afterwards with haematoxylin 

 of Delafield or Bohmer. The mucus cells are shown stained 

 violet. 



HOYER, who has made a special study of the staining reac- 

 tions of mucin in tissues (Arch. f. miJc. Anat., xxxvi, 1890, 

 p. 310; see also Zeit. f. wiss. Mik., viii, I, 1891, p. 67), has 

 the following conclusions : 



The mucin of mucus cells and goblet cells, both of Verte- 

 brates and Invertebrates, stains with basic tar colours, but 

 not with acid tar colours (see above, 788) . More or less 

 specific stains of mucin are obtained, for instance, with 

 hydrochlorate or nitrate of rosanilin, commercial fuchsin, 

 Griibler's "neutral" fuchsin (" n. Unna"), magenta, Magdala 

 red, iodine green, methyl green, dahlia, methyl violet, gen- 

 tian, iodine violet, crystal violet, Victoria blue. A similar 

 reaction is obtained with alum-haematoxylin solutions, whilst 

 carmine behaves like the acid coal-tar dyes, and affords no 

 stain . 



HOYEE obtained his best results by means of thionin (violet 

 of Lauth), which gives a double stain, the tissues blue, the 

 mucin elements ruddy violet. This dye is unfortunately no 

 longer to be found in commerce ; but the dye called amethyst, 

 prepared by Geigy and Co., of Bale, is a good succedaneum, 

 and so are toluidin blue (obtainable from Griibler) or the 

 phenylen blue of Oehler in Offenbach, and the p-phenylen blue 

 of the Hochst manufactory. Like thionin, all these give 

 metachromatic stains. 



Results less brilliant than those given by the above-men- 

 tioned stains, but nevertheless excellent, are obtained by 

 means of methylen blue or Bismarck brown. Methylen green 

 and safranin also give good reactions, but are somewhat in- 

 constant in their effects. Methylen blue is particularly 

 useful from its power of bringing out the merest traces of 

 mucin. 



All of these colours may be used in the same way. Speci- 

 mens should be fixed for two to eight hours in 5 per cent, 

 sublimate solution, imbedded in paraffin, cut, and the sections 

 stained for five to fifteen minutes in a very dilute aqueous 

 solution of the dye (two drops of saturated solution to 5 c.c. 

 of water). 



