CYTOLOGICAL METHODS. 325 



iodine green with 11 parts concentrated aqueous solution of 

 fuchsin, and differentiates in absolute alcohol with 1 per cent, 

 of acetic acid and O'l per cent, of iodine. Nucleoli red, 

 chromatm blue. 



FJSCHBR (Fixirung, etc., p. 140) adds 30 drops of hot O'l 

 per cent, fuchsin solution to 100 c.c. of 0*3 to 0*5 per cent, 

 solution of methyl green. 



MONTGOMERY (Journ. Morpli., xv, 1899) stains for an hour 

 in Ehrlich's haematoxylin, and then for five minutes in con- 

 centrated aqueous eosin, or first with concentrated aqueous 

 methylen blue, and then with concentrated alcoholic solution 

 of Brazilin. 



See also REDDINGIUS, Virchow's Arch., clxii, 1900, p. 206. For nucleoli 

 of ova, LIST, Mitth. Zool. Stat. Neapel, xii, 1896, p. 480 ; of nerve-cells, 

 RUZICKA, Zeit. wiss. Mik., xiv, 1898, p. 453, and LEVI, Rio. Pat. Nerv. 

 Meat. Firenze, iii, 1898, p. 289. 



650. Plasma Stains. I have been unable to discover a 

 single thoroughly satisfactory one. Almost all of them 

 colour too readily the enchylema or hyaloplasm at the same 

 time as the spongioplasm. And, on the other hand, there 

 are many important elements of cells which cannot be got 

 to stain sufficiently. 



I consider Siiurefuchsin the most generally recommendable, 

 especially after iron hamiatoxylin. See also Bordeaux R. 



Flemming's Orange Method has been much used. It is 

 very capricious and unreliable. 



Ehrlich-Biondi mixture is a celebrated plasma stain. 



The Iron-Haemateiu Lakes of Beiida and M. Heidenhain 

 give good plasma stains, according to the degree of extrac- 

 tion, and would be inferior to none were it not that they 

 stain in the same tone as the chromatin. See also Ehrlich/s 

 tri-acid, and his acidophilous mixture, also yold chloride, 

 Apathy's process, 371, and Kemschii'arz, 



Imperfectly stained plasma structures can often be well 

 brought out by mounting in Euparal instead of balsam. 



651. Centrosomes.- -These can be stained by some "acid' 

 anilin dyes, better by a " neutral J dye (e. y. Flemming's 

 orange method, or the Ehrlich-Biondi-Heidenhain stain) . But 

 by far the lest stain is iron-h&matoxylin. 



