636 BOTANICAL TECHNIQUE 



Tech., ii, 1927, p. 31) are also recommended. Taylor recommends 

 Hazen's resin-lanolin mixture ; melt 8 parts of resin and add 

 2 parts lanolin. 



DiEHL {Science, Ixix, 1929, p. 276) has an elegant method of 

 sealing non-resinous mounts. Place a drop of the mounting 

 medium in the centre of a large coverslip, and orient the objects 

 in the medium. Cover the mount with a smaller coverslip, and 

 over this place a large drop of fluid Canada balsam. Cover 

 gently with a slide until the smaller coverslip and the mount are 

 surrounded by a ring of balsam and the balsam also covers the 

 exposed under surface of the larger coverslip. Then invert the 

 slide ; the object is under the one coverslip and is surrounded 

 by a protected balsam seal. 



The balsam tends to run in somewhat, and if water is present 

 in the medium, a cloudy effect is produced. This can be eliminated 

 by carefully painting a thin seal of glycerin jelly around the 

 smaller coverslip ^nd allowing it to dry before applying the 

 balsam. Alternatively seal with immersion oil and ring with 

 balsam. 



Barnard and Welch {Journ. Roy. Micr. Soc, liv (1), 1934, 

 pp. 29-32). Seal wet preparations. 



Using an electrically heated die with the outline of the cover- 

 glass which applies melted wax until perfect fusion results. The 

 apparatus has controlled electric heating of wax reservoir, die and 

 feeder tube. The die carries sufficient heat to perfect the seal 

 but not overheat the preparation. 



RuYTER (Bull. (THistol. AppL, xi, 1934, p. 410) has an improve- 

 ment over Noyer's lake for ringing levulose-gelatin or glycerin 

 preparations* To 100 c.c. liquefied 20 per cent, gelatin in saturated 

 aqueous solution of thyme add 10 c.c. of 5 per cent. KgCrjO, 

 solution, and mix. Preserve in dark. Allow seal to dry at 

 room temperature in the light. 



1263. Mounting Delicate Objects in Resinous Media. Fila- 

 mentous algae and other delicate structures usually collapse 

 hopelessly when handled by the ordinary methods. Dehydration 

 and especially clearing and mounting are for them difficult 

 operations. Such material is best stained in aqueous stains and 

 then placed in a 5 per cent, solution of glycerin in water. Allow 

 this to concentrate by evaporation. Then remove the concen- 

 trated glycerin completely by several washings of 95 per cent, 

 alcohol and two to three changes of absolute alcohol. Infiltrate 

 with Venetian turpentine or Canada balsam. 



1. Venetian Turpentine Method (Pfeiffer and Wellheim, 

 Zeit. wiss. Mik., viii, 1894, p. 29). Transfer the material 

 quickly from absolute alcohol into a 10 per cent, sohition of 

 Venetian turpentine in absolute alcohol, in an open dish in a 

 desiccator over soda lime. Leave here to concentrate. Mount 



