CHAPTER LIII 



PALEOBOTANY 



1414. General accounts of paleobotanical methods are given 

 by : 



Krausel, Die palaobotanischen TJntersuchungsmethoden. Jena, 

 1929. 



HoFMANN, Mikrokosmos (Stuttgart), xxiii, 1930, p. 93. 



JuRASKY, Aherhalden, Handh. biol. Arheitsmethoden, Abt. xi, 

 1931, p. 253 (section methods) and p. 331 (maceration methods). 



PoTONiE, Zeits. Bot., xiii, 1920, p. 79 (maceration and staining). 



Netolitzky, Mikrokosmos (Stuttgart), xx, 1927, p. 178 (methods 

 for carbonised material). 



1415. Maceration Methods. See the papers given above, 

 especially those by Potonie and Jurasky. The most successful 

 macerating fluids are Diaphanol (from Leitz), nitric acid and aqua 

 regia. They also have the effect of bleaching the material and 

 must be removed subsequently by thorough washing with water. 

 Staining can sometimes be attempted ; try safranin or- ha;ma- 

 toxylin in the first instance. 



1416. Sectioning Methods. Formerly most of the harder 

 fossils were sectioned by grinding, following geological methods. 

 Cut thin slabs through the specimen in the desired direction with 

 a hack-saw or band-saw of the type used for cutting mineral 

 specimens. The blade must be of the hardest temper. The 

 operator of a band-saw must be thoroughly protected. Then 

 grind the specimen as thinly as possible while being held in the 

 hand, and polish one surface. Cement the polished surface to a 

 glass slide. When firmly attached complete the grinding and 

 polishing, wash, dry with alcohol, clear if necessary and cover 

 with balsam and a cover-glass. The details of the method depend 

 very largely upon the matrix. Exercise caution when the section 

 is approaching the desired thinness to ensure an even thickness 

 and to prevent it breaking up. Some friable specimens should be 

 saturated with resin before grinding. Hoskins (Bot. Gaz., Ixxxix, 

 1930, p. 414) describes a transfer method for sections. Lomax 

 {Jovrn. Roy. Micr. Soc, xlvii, 1927, p. 239) describes the technique 

 of making coal sections. First coat the block with shellac to 

 prevent absorption of moisture and then grind the end level, 

 heat to remove moisture and coat with shellac. Next heat the 

 block in an oven and then cool. Smooth the ground end with 

 fine carborundum on a glass plate, and again shellac and dry the 



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