MYELIN STAINS. 415 



Strong (Joura. Comp. Newr., xiii, 1903, p. 291) finds bichromate of 

 copper (of 2 to 3 per cent.) the best mordant; and that the mordanting 

 is best done before bringing into celloidin. After staining, lie treats 

 for half a minute with osmic acid of 0'25 per cent., and difEerentiates 

 as Pal. 



798. Makchi's Method (for Deganerats Nerves) [Rlvista 

 spurim. di Frenintrla, 1887, p. 208; Zeit. wiss. Mile., ix, 

 1893, p. 350). — Small pieces of tissue are hardened for a 

 week in solution of Miiller, and then put for a few days 

 into a mixture of 2 parts solution of Miiller and 1 part 1 per 

 cent, osmic acid solution. Sections are cut, best without 

 imbedding, and mounted in balsam. The sheaths in normal 

 nerves then acquire a yellow coloration, those of degenerated 

 tracts a black one. 



This process therefore gives positive images of the 

 degenerated elements, Weigert's process only giving negative 

 ones. 



For a critical review of this method and its modifications 

 see Weigert, in Ergebnisse der Anatomie, vii, 1897 (1898), 

 pp. 1 — 8; Mathszewskt, Arch. path. Anat., 1905, p. 12; de 

 Lange, Le Nevraxe, x, 1909, p. 83 ; and Lewy, Fol. Neurobiol., 

 ii, 1909, p. 471 {Zeit. iviss. Mile, xxvi, 1909, p. 290). 



The method has been applied to tissues that have been hardened in 

 formal; but this, according to Weigkbt, does not seem recommendable. 



FxNOTTi {Virchow's Arch., cxliii, 1896, p. 133) makes 

 sections of material that has been in liquid of Miiller for 

 not more than a few weeks or months, and puts them for 

 four to ten hour.s (in the dark) into a freshly prepared 

 mixture of one or two parts of 1 per cent, osmic acid and 

 one part of a concentrated solution of iiicric acid in one-third 

 alcohol. For peripheral nerves, myelin (normal), black. 



Ore [Journ. Path, and Bad., vi, 1900, p. 387 ; Journ. Roy. 

 Mic. Soc, 1900, p. 399) treats with a mixture of 8 c.c. of 

 2 per cent, osmic acid, and 2 c.c. 1 per cent, acetic acid, 

 which increases the penetration. 



Vassale {Arch. ital. Biol., 1895, p. 91) takes 75 c.c. of 

 solution of Miiller, 25 c.c. of 1 per cent, osmic acid, and 

 20 drops of nitric acid. 



NissL {Encycl. mile. Ttchidk, ii, p. 248), holding that 



