14 METHODS IN PLANT HISTOLOGY 



brass tubing, 1 inch square. Cut the tubing into pieces 10 or 12 cm. 

 long, saw off one side, and solder pieces into the ends with hard solder. 

 The brass plate can be heated with any kind of flame at the pointed 

 end. 



Since the Venetian turpentine method has almost entirely displaced 

 the glycerin method, the turntable is disappearing from the botanical 

 laboratory; but some objects, like Nemalion and moss protonema, are 

 still mounted in glycerin or glycerin jelly; and so one still finds occa- 

 sional use for this once necessary piece of apparatus. A serviceable 

 form is shown in Figure 10. More expensive turntables, with devices 



Fig. 10.— Turntable 



for automatic centering, present no practical advantages, and the 

 centering devices are often in the way. 



Much histological work usually done with scalpels can be done with 

 safety razor blades, especially since holders of the Gits type have be- 

 come common. For trimming paraffin blocks and handling paraffin 

 ribbons, a more rigid type is necessary. A scalpel with a straight edge 

 is preferable. 



Needles are used so constantly that it is well to have clamping 

 holders. However, nothing is quite equal to a rather large handle 

 whittled out from a piece of light pine. 



Scissors are seldom used in the botanical laboratory except for 

 cutting out labels. Rather stout scissors, with blades about 2\ inches 

 long, are best for general purposes. 



It is convenient to have two pairs of forceps, a strong pair for han- 

 dling slides and a lighter pair, preferably with broad shovel-shaped 

 points, for handling cover glasses. Curved forceps are not necessary; 

 the cover-glass forceps, used by bacteriologists for staining on the 

 cover, are of no use in botanical histology. 



