696 GENERAL TECHNIQUES FOR CLASSES OF PLANTS 



Maj'er's haemalum, safranin and phloxine (Magdala red) ; counter- 

 stain (if necessary) with erythrosin. orange G., anilin blue, cyanin 

 or light green. Newton's gentian violet-iodine gives excellent 

 results on sections and filamentous types. 



After staining, dehydrate whole material in glycerine and mount 

 in Venetian turpentine or Canada balsam. G.H.C. {Turtox News, 

 iii, p. 45) washes out the glycerin with absolute methyl alcohol, 

 to which a very little light green is added. 



Geitler {Osterr. Bot. Zeits., Ixxi, 1922, p. 116) advocates fixing 

 living algse in boiling 5 to 10 per cent. AgNO., solution for thirty 

 seconds to five minutes to fix the cell contents and at the same time 

 bring out the chloroplasts which take on a brown to black colora- 

 tion. 



Dilute aqueous methylen blue stains the cell-walls of algae very 

 readily. Cotton blue dissolved in Amann's lactophenol is useful 

 for general structure (see Fungi). See also Davis, Science, Ixxi, 

 1930, p. 16. Harris (Watson's Micr. Rec, 1924 (3), p. 9) 

 recommends Hofmann's blue after potassium permanganate and 

 alum for freshwater algae. Burton (J. Queckett Micr. Club, 2nd 

 Ser., XV, 1923, p. 45) uses Hofmann's blue in 25 per cent, glycerin. 



Chodat (C. R. Soc. Phys. Hist. Nat. Geneve, xli, 1924, p. 140) and 

 Deflandre (Bull. Soc. Bot. France, Ixx, 1923, p. 738) use nigro- 

 sin ; Curtis and Colley (Am. J. Bot., ii, 1915, p. 89) picro- 

 nigrosin. The cell- walls stain faintly, but the protoplasmic 

 elements stand out in brilliant contrast against the black back- 

 ground. It is useful for most Myxophj'ceae and some Chloro- 

 phyceae. 



Powers (see Chamberlain, p. 217) stains Volvoca'ceae in Mayer's 

 carmalum. See also Shaw, Philippine Joiirn. Sci. Bot., xiii, 

 1918, p. 241. Margolena {Stain Tech., vi, 1931, p. 47) uses 

 Feulgen's stain for small forms. Methyl green in 1 per cent, 

 acetic acid and Belling's iron aceto-carmine are most useful for 

 living forms. See especially. Brand, Arch. Protistenk., Iii, 1925, 

 p. 265. 



Alcorn {Stain Tech., x, 1935, p. 107) fixes desmids in 2 to 3 per 

 cent, formaldehyde, to which a few drops of acetic acid have been 

 added. Dehydrate, by decantation, through close alcohol grades 

 (each 5 per cent, apart), about ten to fifteen minutes in each. 

 Stain twelve to forty-eight hours in light green S.F. yellowish or 

 fast green F.C.F. (1 per cent, in 95 per cent, alcohol). Wash in 

 95 per cent, and absolute alcohol, ten to fifteen minutes each. 

 Clear in xylol series and mount in balsam. 



1381. Taylor's Method for Sheath Structure of Desmids 

 {Trans. Amer. Microsc. Soc, xl, 1921, p. 94). Place fresh living 

 material in 0-05 per cent, aqueous methylen blue for forty-five 

 to sixty seconds. Remove, rinse in distilled water and place 

 in one-tenth saturated aqueous picric acid. This fixes the stain 



