OTHER STAINS AND COMBINATIONS. 229 



Iron-Brazilin (HJCKSON, Quart. Journ. Micr. Sci., xliv, 

 1901, p. 470) is better. Sections are mordanted for 1 to 

 3 hours in 1 per cent. sol. of iron alum in alcohol of 70 

 per cent, (made by dissolving 1 grm. of the salt in 23 c.c. 

 of water, warm, and adding 77 c.c. of 90 per cent, alcohol 

 after cooling), rinsed with alcohol, and put for 3 to 16 hours 

 into 0*5 per cent. sol. of Brazilin in alcohol of 70 per cent. 



379. Orchella (Orsaille) see WEDL (Arch. path. Anat.,lx.x.iv, p. 143) ; 

 and FOL (Lehrb., p. 192), and early editions of this work. 



380. Orcein (ISRAEL, Virchow's Archiv, cv, 1886, p. 169 ; and Prakti- 

 cum der path. Hist., 2 Aufl., Berlin, 1893, p. 72) is a dye obtained from 

 the lichen, Licanora parella, and is not to be confused with orcin, 

 another derivative of the same lichen. It is said to unite in itself the 

 staining properties of the basic and acid stains, and also the combina- 

 tion of two contrast colours. Israel stains sections in a solution 

 containing 2 grins, of orcein, 2 grins, of glacial acetic acid, and 100 c.c. 

 of distilled water, washes in distilled water, and passes rapidly through 

 absolute alcohol to thick cedar oil, in which the preparations remain 

 definitely mounted. Nuclei blue, protoplasm red. 



See also " Connective Tissues " in Part II, and LAURENT, Zeit. wiss. 

 Mik., xiii, 1896, p. 302 ; RUZICKA, ibid., xiv, 1898, p. 455 ; and WOLFF, 

 ibid., xix, 1903, p. 488. 



381. Purpurin, see RANVIER'S Trai'e technique, p. 280; DUVAL'S 

 Precis de Technique histologlque, p. 221 ; and GEENACHER'S formula in 

 Arch. Mile. Anat., xvi, 1879, p. 470. A very weak stain. 



382. Indigo. Indigo is employed in histology in the form of solu- 

 tions of so-called indigo carmine, or sulphindigotate of soda or potash- 

 The simple aqueous solution gives a diffuse stain, but is of use when 

 employed in conjunction with carmine, see below. 



Thlersch's Oxalic Acid Indigo-carmine (see Arch. mile. Anat., i, 

 1865, p. 150). 



383. Other Vegetal Dyes. See early editions. Those recom- 

 mended by CLAUDIUS (Zeit. wiss. Mile., xvii, 1900,p. 52) are superfluous. 



Carmine Combinations. 



384. Seller's Carmine followed by Indigo-Carmine (Am. Quart. 

 Mic. Journ., i, 1879, p. 220). Stain in borax-carmine, wash out with HC1 

 alcohol, wash out the acid, and after-stain, in an extremely dilute alco- 

 holic solution of indigo-carmine (two drops of saturated aqueous solution 

 added to an ounce of alcohol and filtered). 



I find this method gives good results with sections, but not if it be 

 att mpted to stain in bulk. 



