FIG. 1. Strawberry, cellular tissue 2. Buttercup leaf, internal layer 3. Privet, Seed Coat, showing star-shaped cells 4. Rush, Star-shaped cells 5. Mistletoe, cells with ringed fibre 6. Cells from interior of Lilac bud 7. Bur-reed (_Sparganium_), square cells from leaf 8. Six-sided cells, from stem of Lily 9. Angular dotted cells, rind of Gourd 10. Elongated ringed cells, anther of Narcissus 11. Irregular star-like tissue, pith of Bulrush 12. Six-sided cells, pith of elder 13. Young cells from Wheat 14. Do. rootlets of Wheat 15. Wood-cells, Elder 16. Glandular markings and resin, “Cedar” pencil 17. Do. Yew 18. Scalariform tissue, Stalk of Fern 19. Dotted Duct, Willow 20. Do. Stalk of Wheat 21. Wood-cell, Chrysanthemum 22. Do. Lime-tree 23. Dotted Duct, Carrot 24. Cone-bearing wood, Deal 25. Cells, outer coat, Gourd 26. Ducts, Elm 27. Cellular tissue, Stalk of Chickweed 28. Holly-berry, outer coat [Illustration: I.] On Plate I. Fig. 1, may be seen three cells of a somewhat globular form, taken from the common strawberry. Any one wishing to examine these cells for himself may readily do so by cutting a very thin slice from the fruit, putting it on a slide, covering it with a piece of thin glass (which may be cheaply bought at the optician’s, together with the glass slides on which the objects are laid), and placing it under a power of two hundred diameters. Should the slice be rather too thick, it may be placed in the live-box and well squeezed, when the cells will exhibit their forms very distinctly. In their primary form the cells seem to be spherical; but as in many cases they are pressed together, and in others are formed simply by the process of subdivision, the spherical form is not very often seen. The strawberry, being a soft and pulpy fruit, permits the cells to assume a tolerably regular form, and they consequently are more or less globular. Where the cells are of nearly equal size, and are subjected to equal pressure in every direction, they force each other into twelve-sided figures, having the appearance under the microscope of flat six-sided forms. Fig. 8, in the same Plate, taken from the stem of a lily, is a good example of this form of cell, and many others may be found in various familiar objects. We must here pause for a moment to define a cell before we proceed further.