CHAPTER XLIX 



SOME METHODS OF SPECIAL STAINING VITAL STAINING 

 AND CYTOPLASMIC STRUCTURES 



1317. Living MateriaL Relatively few plant structures {e.g 

 unicellular and filamentous plants, pollen mother-cells, hairs, 

 stripped epidermis) are adapted to intravital observation. 



1318. Coloured cell structures (chloroplasts, chromatophores, 

 eyespots) are best examined in the living state and require no 

 special treatment. Chromatophores with faint pigmentation are 

 made more evident by a suitable screen placed below the con- 

 denser (see Plastids). 



For methods of investigating living cells of cambium see 

 Bailey {Zeits. Zellforsch. Mikr. Anat., x, 1930, p. 651) and 

 Priestley, Scott and Malins {Proc. Leeds Phil, and Lit. Soc, ii, 

 1933, p. 365). Bailey kept cambial initials alive and actively 

 streaming for 500 hours in saccharine solutions and " white 

 Russian oil." 



Martens {Bull. d'Histol. Appl., v, 1928, p. 229) studies the 

 resting nucleus of living cells during the process of fixation. 



See also Favorskii {Mem. Soc. Nat. Kieff., xxvii, 1926, p. 71) 

 for the so-called chromolytic method of studying living cells. 



Dark Ground Illumination. See Price, Ann. Bot., xxviii, 

 1914, p. 601 ; Strangeways and Canti, Quart. J. Micr. Sci., 

 Ixxi, 1927, p. 1. 



1319. Micro-culture Chambers. Kirchner {Die mikroskopische 

 PJlanzemvelt des Susswassers, 1885, Braunschweig) and Vosseler 

 {Zeits. Wiss. Mikr., vii, 1890, p. 457) use a square covershp 

 supported on a slide at its corners by small wax feet ; the wax is 

 made by adding to melted wax half to one-third its bulk of 

 Venetian turpentine, stirring constantly, 



1320. Hanging-drop methods consist essentially in a coverslip, 

 with a drop of a suspension of the material on its lower side, 

 supported on a wall built up on the slide ; a fair volume of air is 

 thereby provided. The van Tieghem cell is the best, and consists 

 of a short piece of wide glass tubing cemented to the slide with 

 balsam. 



See also Farr {Science, Ivi, 1922, p. 227), Murneek and Yocum 

 {Plant Physiol., ii, 1927, p. 506). 



1321. Continuous Flow (Siphon) Chambers. Klercker (C/nfer- 

 suclu hot. Inst. Tubingen, ii, p. 333) uses a chamber prepared by 

 cementing two strips of glass (about 0-15 mm. thick) to a slide 



668 



