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METHODS IN PLANT HISTOLOGY 



It is a good plan to cut the wood into pieces suitable for cutting, so 

 that the sections will be about 5X7 mm. Boil these pieces for 24 hours 

 and then put them into equal parts of 95 per cent alcohol and glycerin 

 for at least a week. After the boiling, very hard woods should be 

 treated with 25 per cent hydrofluoric acid for a week and then washed 



Block to be cut 



u 



I Bunsen 



Fig. 25. — Apparatus for steam method 



thoroughly in water before being placed in glycerin and alcohol. A 

 soft wood, like Pinus strohus, needs no steam or previous treatment, 

 except a few hours' soaking in water. 



Kisser cut transverse sections, 5 mm. square, of ebony. Sections of 

 cocoanut shell 2 mm. square and 6 /x thick were cut smoothly. 



JEFFREY'S VULCANIZING METHOD 



Jeffrey cut very thin sections of the hardest woods and even such 

 refractory material as peach stones and the shells of various nuts. 



