342 TEGUMENTARY OEGANS. 



CHAPTER XXVIL 



TEGUMENTARY OEGANS. 



646. Epithelium. One of the chief methods of obtaining 

 preparations giving instructive surface views of epithelia is 

 the nitrate of silver method. For this see ante, 212, et seq., 

 in the chapter on " Impregnation Methods." The reader 

 may also consult with advantage the admirable instructions 

 given by KANVIEE in his Traite technique, p. 246, et seq., 

 and the memoir of TOUENEUX and HEEMANN in the Journ. 

 de I'Anat., 1876, p. 200. 



The perchloride of iron and pyrogallic acid method of the 

 HOGGANS, 231, and the osmic acid and pyrogallic acid pro- 

 cess, 233, may also be found useful here. But in many 

 cases impregnation with methylen blue will doubtless be 

 found preferable (see 113, et seq., and especially 120 and 

 121). 



KEOMAYEE'S process for demonstrating his intra- and inter- 

 cellular fibrils of epithelia (Arch.f. mik. Anat. } xxxix, 1892, 

 p. 141; Zeit.f. wiss. Mik., ix, 1, 1892, p. 84, and ix, 3, 1893, 

 p. 355) is as follows : Sections are stained for five minutes 

 in a mixture of equal volumes of anilin water ( 101) 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 

 anilin 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 Krystallviolett will do instead of methyl violet, 

 but not quite so well. For a discussion of the points of dif- 

 ference between the fibrils of Kromayer and the fibres of 

 HEEXHEIMEE, see EHEMANN, and JADASSOHN, Arch. f. Der- 



