246 



INDEX 



Vessels, sealariform, 121, *123 

 — , spiral, 121, *123 

 — , structure of, 121 

 — , walls of, 121 

 Virtual images, 28, *29 



W 

 Water, absorption of, 113 

 — ■ pores, 118 

 Wood, cell contents, 182 

 — , definition, 177 



— fibers, '80, *106, *107, 108, 



*180, *181. 

 — , medullary rays, 179, *180, 

 *181 



— parenchyma, 178, *181 



Wood, pith, 182 



— structures, 177, *180, *181 

 — , xylem elements, 178 

 Working distance, *34, 38 



Xylem bundles, *78, 80 



— elements in woods, 178, *180, 



*181 



— fibers, 80, *106, *107, 108, 



*180, *181 



Zenker's fluid, 229 



Zinc chloriodide solution, 229 



