314 CYTOLOGICAL METHODS. 



method are not necessarily chromatinic. Occasionally this method 

 seems to overstain genital cells, but this gives the correct degree of 

 chromophility of such cells in comparison with the cells of other tissues. 

 After having used the method critically, I have come to the conclusion 

 that it is more precise than the usual procedure which introduces 

 differentiation in an acid solution. Scott worked out this method 

 mainly with sections of mammalian red bone marrow. 



669a. OBST (Zeit. wiss. ZooZ.,lxvi, 1899) fixes in sublimate, stains in 

 borax carmine, and then stains the sections for three hours in very dilute 

 aqueous methyl green or solid green. Nucleoli blue, chromatin red. 



BUCHNER (Arch. Zellforsch., iii, 1909, p. 337) has found this useful for 

 distinguishing the accessory chromosome in testis cells of Orthoptera 

 normal chromosomes red, accessory and chromatin nucleoli blue-violet. 



ZIMMERMANN (Zeit. wiss. Mik., 1896, p. 463) stains for ten minutes in 

 a fresh mixture of 9 parts 0-1 per cent, aqueous iodine green with 1 part 

 concentrated aqueous solution of fuchsin, and differentiates in absolute 

 alcohol with 1 per cent, of acetic acid and 0-1 per cent, of iodine. Nucleoli 

 red, chromatin blue. 



FISCHER (Fixirung, etc., p. 140) adds 30 drops of hot 0-1 per cent, 

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

 green. 



MONTGOMERY (Journ. Morph., xv, 1899) stains for an hour in Ehrlich's 

 haematoxylin, and then for five minutes in concentrated aqueous eosin, 

 or first with concentrated aqueous methylen blue, and then with con- 

 centrated alcoholic solution of Brazilin. 



For a series of papers on staining nucleoli, and illustrated by 

 profuse coloured plates, see MAX JORGENSEN'S memoirs in the Arch, 

 f. Zellf., x, 1913. Another paper worth consulting is CHAMPY'S 

 magnificent work on the male germ-cells of amphibia in the Arch, 

 de Zool Exper., 1913. 



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

 nucleoli of ova, LIST, Mitth. Zool. Stat. Neapel, xii, 1896, p. 430 ; of 

 nerve-cells, RUZICKA, Zeit. wiss. Mile., xiv, 1898, p. 453, and LEVI, Eiv. 

 Pat. Nerv. Ment. Firenze, iii, 1898, p. 289. 



670. Plasma Stains. Dr. Bolles Lee states that he has 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. 

 We consider Saurefuchsin and Biebrich scarlet the most generally 

 recommendable, especially after iron hsematoxylin. 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. 



