MARCHES METHOD. 379 



2 drops of glacial acetic acid for each cubic centimetre, and finally (without 

 previous washing with water) are stained for fifteen to twenty minutes in 

 aqueous solution of China blue (the best China blue for this purpose is that 

 supplied by the Badische Anilin- und Soda-Fabrik, at Stuttgart). They 

 are washed out in alcohol, cleared in essence of turpentine, and mounted in 

 dammar. 



For the results see the paper and the plate, 1. c. 



PLAINER (Zeit. f. wiss. Mik., vi, 2, 1889, p. 186) obtains a specific stain 

 of the neuroceratin framework of medullated nerve in the following way : 

 Small nerves are fixed and hardened for several days in a mixture of 1 part 

 of Liq. Ferri Perchlor. (Ph. G. Ed. ii) and 3 to 4 parts of water or alcohol. 

 They are then to be washed out in water or alcohol till no traces of iron 

 remain in them (the reaction of the washings with rhodanide of potassium 

 being a good test of this), and are stained for several days or weeks in a con- 

 centrated solution of "Echtgriin" (dinitrosoresorcin, not " dinitroresorcin," 

 as erroneously in Platner's paper) in 75 per cent, alcohol ; after which they 

 are dehydrated, imbedded, and sectioned. 



See also the papers of GEDOELST in La Cellule, iii, 1887, p. 117, and v, 

 1889, p. 126 (good details of digestion methods) ; also the report in Zeit. f. 

 wiss. Mik., vii, 1, 1890, p. 57. 



Further, in general, RANVIBE, Traite. p. 718, et seq. ; REZ- 

 ZONICO, Arch, per le Sci. Med., 1879, p. 237 ; TIZZONI, ibid., 

 1878, p. 4 (a process of boiling in chloroform for an hour or 

 two, then staining and mounting in glycerin) ; BOVERI, Zeit. 

 f. iviss. Mik., iv, 1, 1887, p. 91 ; JAKIMOVITCH, Journ. de I'Anat,, 

 xxiii, 1888, p. 142, or Zeit. f. wiss. Mile., v, 4, 1888, p. 526 

 (instructions for impregnating the axis-cylinder with silver, 

 followed by reduction in formic acid and amyl alcohol) ; 



SCHIEFFERDECKER, in BEHRENS, KOSSEL, U. SCHIEFFERDECKER, 



Das Mikroskop, Bd. ii, p. 227. 



720 a. MARC HI'S Method for Degenerate Nerves. I have not 

 been able to find out where this was first published, and take 

 the following from the report by Schiefferdecker of a paper 

 by EIJKMAN, in Zeit.f. wiss. Mik., ix, 3, 1893, p. 350. Nerves 

 are first 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. The treat- 

 ment with the chrome salt deprives the medullary sheath of 

 normal fibres of the faculty of impregnating with osmium, 

 whilst the degeneration products in diseased sheaths retain 

 that faculty. In consequence the sheaths in normal nerves 

 acquire a yellow coloration, those of degenerated tracts a 

 black one. 



