450 CONNECTIVE AND ELASTIC TISSUES 



connective networks black, nerve fibres unstained or only weakly 

 stained. 



Perdrau {Journ. Pathol. Bad., xxiv, 1921) has worked out a 

 modification of Bielschowsky which appears to be particularly 

 suitable for the study of the connective tissue in nervous organs. 

 He washes pieces and sections as in Da Fano's modifications, but 

 without having recourse to re-distilled water. He then places 

 sections for about ten minutes in 0-25 per cent, potassium per- 

 manganate, washes, and treats them as by Pal's modification of 

 Weigert's myelin stain (see § 1058). After another wash in 

 distilled water, he transfers sections into 2 per cent, silver nitrate, 

 and continues as in Da Fano's Mod. 1. Nerve-cells, nerve-fibres, 

 neuroglia, etc., unstained ; connective tissue and elastic fibres 

 stained in various shades of purple-grey to black. Refer to 

 § 1055. 



967. H. Wilder's Silver Impregnation Method for Reticulum 

 Fibres (Amer. Journ. Path., xi, 1935). Fix in 10 per cent, formol, 

 acetic Zenker or formol Zenker. Mount paraffin sections with 

 egg albumen, and bring down to water. Place in 1 per cent. 

 pot. permanganate for half to one minute. Wash in distilled 

 water. Place in 5 per cent, oxalic acid for one minute. Wash 

 well in distilled water. Place in 1 per cent, uranium nitrate for 

 five to ten seconds. Rinse rapidly in distilled water. 



Place in the following solution for one minute : — 



To 5 c.c. of a 10-2 per cent, silver nitrate solution, add ammonia 

 drop by drop until the precipitate disappears. Add 5 c.c. of a 

 3-1 per cent, solution of NaOH, and just dissolve the resulting 

 precipitate with a few drops of ammonia. Make up to 50 c.c. 

 with distilled water. 



Dip quickly in 90 per cent, alcohol. 



Reduce for one minute in the following solution :- 



Distilled water ..... 50 c.c. 

 40 per cent, neutral formalin ' . . 0-5 ., 



1 per cent, uranium nitrate . . . 1*5 ,,, 



Wash in distilled water. Tone in 0-2 per cent, gold chloride 

 for half to one minute. Rinse in distilled water. Place in 

 5 per cent, hypo for one to two minutes. Wash well in water. 

 This is a remarkably good method recommended by K. C. 

 Richardson. 



See also Maresch, Zeit. zciss. Mik., xxiii, 1906, p. 356 ; Stud- 

 NicKA, ibid., p. 416 ; Zimmermann, ibid., xxv, 1908, p. 10 ; Levi, 

 Monit. zool. Ital., 1908, p. 290 ; Heinrich, Arch. mik. Anal., 

 Ixxiv, 1909, p. 786 (dentine) ; Insabato, Arch. Ital. Anat. Emb., 

 viii, 1909, p. 375 (silvers Flemming material) ; Athanasiu and 

 Dragoiu, C. R. Acad. Sci., cli, 1910, p. 551 (Ramon y Cajal's 

 silver process, with alcohol fixation). 



