332 CHAPTER XXVII. 



UNNA (Monatsschr. prakt. Derm., xxxvii, 1903, p. 1) has 

 described a highly complicated process with Wasserblau and 

 orcein, see Zeit. iviss. Mik., xxi, 1904, p. 68. 



656. Plasma-fibrils of Epithelium. KROMAYER'S process 

 (Arch. inik. Anat., xxxix, 1892, p. 141) is as follows : Sections 

 are stained for five minutes in a mixture of equal volumes 

 of anil in water ( 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 vol. of anil in to 2 vols. of xylol 

 until sufficiently differentiated, when they are brought into 

 pure xylol. Very thin sections will require more xylol in 

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

 require more anilin, viz. 3 : 5 or 3 : 3. Gentian or Krystall- 

 violett will do instead of methyl violet, but not quite so well. 

 See also EHRMANN and JADASSOHN, Arcli. Dermatol. u. Syphilis, 

 1892, 1, p. 303 ; Zeit. iriss. Mil:, ix, 1893, p. 356 ; HERX- 

 HEIMEI:, Arch. 'inik. Anat., liii, 1899, p. 510 ; and ROSENSTADT, 

 iltid., Ixxv, 1910, p. 659 (takes the differentiating mixture 

 much weaker in .anilin). 



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

 277, et se<j[. ; Zeit. wiss. Mik., xii, 1, 1895, pp. 61, 63) has 

 given a whole series of methods, from which the following 

 are some extracts. 



(1) WASSERULAU-()RCUIN. 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 Grubler's orcein. Dehydrate, clear, and 

 mount in balsam. This may be varied as follows : 



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

 more in the orcein. 



(/;) 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 

 hajinalum, 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. 



