SPECIAL METHODS 



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As soon as the young shoots are s to lo cm. long, raise the 

 inner glass tube sHghtly (Fig. 13, B) and push the cotton 

 firmly around the base of the young shoot. This should 



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Fig. 13.— Apparatus for growing seedlings free of bacteria. 



be repeated two or three times until there is a cotton 

 plug of 3 to s cm. around the shoot. Now remove the 

 inner cylinder, excess cotton, and glass rods. 



