340 TEGUMENTARY ORGANS. 



( 286) and concentrated aqueous solution of methyl violet 6 B. 

 They are well washed in water and treated with solution of iodine 

 in iodide of potassium until they become blue-black (one to thirty 

 seconds). They are again washed with water, dried with blotting- 

 paper, and treated with a mixture of 1 volume of anilin to 2 volumes 

 of xylol until sufficiently differentiated, when they are brought 

 into pure xylol. Very thin sections will require more xylol in pro- 

 portion to the anilin, viz. 1 : 3 or 1 : 4 ; thicker ones may require 

 more anilin, viz., 3 : 5 or 3 : 3. Gentian or Krysfcallviolett will do 

 instead of methyl violet, but not quite so well. See also EHRMANN 

 and JADASSOHN, Arch. Dermatol. u. Syphilis, 1892, 1, p. 303 ; Zeit. 

 iviss. Mik., ix, 1893, p. 356 ; HERXHEIMER, Arch. mik. Anat., liii, 

 1899, p. 510 ; and ROSENSTADT, ibid., Ixxv, 1910, p. 659 (takes the 

 differentiating mixture much weaker in anilin). 



UNNA (Monatsschr. prakt. Derm., xix, 1894, p. 1 and pp. 277 et 

 seq. ; Zeit. wiss. Mik., xii, 1, 1895, pp. 61, 63) has given a whole 

 series of methods, from which the following are some extracts. 



(1) WASSERBLAU-ORCEIN. Stain sections for ten minutes in a 

 neutral aqueous 1 per cent, solution of Wasserblau, rinse and stain 

 for five or ten minutes in a neutral alcoholic 1 per cent, solution of 

 Griibler's orcein. Dehydrate, clear, and mount in balsam. This 

 may be varied as follows : 



(a) Ten minutes in the Wasserblau and thirty minutes or more 

 in the orcein. 



(b) Take for the second stain an acid solution of orcein. 



(c) Stain for only one minute in the Wasserblau, but for thirty 

 or more in the neutral orcein. 



(2) Stain for half an hour or more in a strong solution of hsemalum, 

 rinse, stain for half a minute in a saturated aqueous solution of 

 picric acid, and dehydrate for thirty seconds in alcohol containing 

 0*5 per cent, of picric acid. 



(3) Haemalum for two hours, neutral orcein as above for ten to 

 twenty minutes. 



More recently UNNA advocates the process mentioned last 

 section. 

 See also KANVIER, Arch. Anat. Mikr., iii, 1899, p. 1. 



717. Keratohyalin. The keratohyalin granules of the cells of 

 the stratum granulosum are soluble in mineral acids, and can be 

 digested in pepsin. They can be stained with picro -carmine, alum 

 heematoxylin, van Gieson's mixture, or Unna's Wasserblau-orcein, 

 last . FICK (Centralb. allg. Path., xiii, 1902, p. 987 ; Zeit. wiss. 

 Mik., xx, 1903, p. 222) stains sections of alcohol material for three 



