TYPE PREPARATIONS 



57 



Structure of Timber, Old Wood of Pine, 'Pinus sylvestris.' 

 Prepare half-inch cubes of old wood of pine, Fig. 27. Steep the cubes in 

 tepid water for twenty-four hours to soften. 



A. B. 



Fig. 27. — A. Diagram of a cross section of a timber tree, showing the position from which 

 to cut out a cube for section izing, a, central axis of growth, h, cube. B. Cube 

 after removal from A, b. a, transverse surface, b, radial-longitudinal surface, 

 c, tangential longitudinal surface. 



a. Cut sections ^/looo of ^n inch in thickness from the transverse surface of cube. 



/;. Cut sections ^/'looo of an inch in thickness from the radial longitudinal 

 surface of cube. 



c. Cut sections ^/moo of an inch in thickness from the tangential longitudinal 

 surface of cube. 



Place the three series of sections in water as cut, separately. 

 Bleach all the sections, and transfer to 92% alcohol. 



Manipulation for a and c, Nos. 3 and 12. Manipulation for h; . 



1. Place the sections in equal parts of alcohol, glycerine, and water; allow to 

 stand six hours. 



2. Place* the sections in two parts of pure glycerine and one part each of alcohol 



and water; allow to stand three hours. 



3. Place the sections in pure glycerine. 



4. Mount the sections in glycerine jelly (without staining). 



Compare the preparations with Figs. 24, 25, 26. Plate VII. 



