62 THE CELL. 



solved Canada balsam, invert the cover, and place in the centre of 

 a slide. Examine with the microscope. In successful preparations 

 the cells (corpuscles) retain their form nearly unchanged, the nuclei 

 are colored bright blue, and the protoplasm (stroma) bright red. 



4. Tease out in water the very young anther of some flower- 

 ing plant preserved in alcohol. Examine, and treat with iodine. 

 Treat another specimen with 2$ acetic acid colored vivid green 

 by the addition of a little aqueous solution of methyl green. 

 Observe the protoplasm, cell-membranes, and nuclei. If the 

 specimen be of the proper age, the cells (inotlier-cells of the 

 pollen-grains] may be observed dividing to form the pollen-grains. 



5. Examine mature pollen-grains of various kinds of flower- 

 ing plants. Mount them dry on a slide. 



6. Examine young spores from the developing fruit (sporo- 

 gonium] of a moss or fern. Stain with iodine. Afterwards ex- 

 amine mature spores from another specimen. 



7. Soak a piece of pine-wood in glycerine, make a delicate 

 longitudinal section with a razor, mount in glycerine, and exam- 

 ine. Note the thick-walled, empty, elongated wood-cells, and 

 the numerous openings (bordered pits] in the walls. 



8. Make a thin longitudinal section radially through a well- 

 developed stem of Pelargonium. Search for and examine 



(a) Elongated cells (pitted tracheids) with walls marked by 

 numerous hollows or pits ; 



(I) Elongated cells (spiral and annular vessels) whose walls 

 have spiral or ring-shaped thickenings inside. 



9. Make a transverse section through the stem of the yellow 

 water-lily (Nuphar). Examine the curious star-shaped cells scat- 

 tered through the tissue. The stem of the white water-lily 

 (Nymphcea] shows similar cells. 



10. Examine hairs from the lower side of a leaf of Deutzia^ 

 which miy be procured in any hot-house. 



11. Examine collenchyma (tissue with the cell-membranes 

 thickened at the angles) in cross-sections of the stem of Pelar- 

 gonium, or Sunflower, or the leaf-stalk of Begonia. 



12. Examine the sub-epidermal cells in cross-sections through 



