360 THE MICROSCOPE. 



Vegetable tissues are best prepared for the microscope 

 by making thin sections, either by maceration, by tearing be- 

 tween the thumb and the blade of a knife, or by dissection. 



Th3 spiral and other vessels of plants require to be 

 dissected out under a simple magnify ing-glass. Take, for 

 instance, a piece of asparagus, and separate with the 

 needle-points the vessels, which require to be finished 

 under a magnifying-glass, in a single drop of distilled 

 water. When properly done, keep in spirits of wine and 

 Tater until mounted. 



Vascular tissue requires both maceration and dissection 

 for its separation. The cuticle or external covering of 

 plants is an interesting structure; but the beauty of all 

 vegetable tissues is greatly enhanced by staining a? 

 directed in a previous chapter. 



Cellular tissue maybe studied in fine sections from the 

 pith of elder, pulp of peach, pear, &c. The petals of flowers 

 are mostly composed of cellular tissue; their brilliant co- 

 louring arises from the action of light upon the fluid con- 

 tents of the cells. In the petal of the anagallis, or scarlet 

 chickweed, the spiral vessels diverging from the base, and 

 the singular cellules which fringe the edge, are interest- 

 ing objects ; the petal of the geranium being one of the 

 most beautiful for microscopic examination. The usual 

 way of preparing it is by immersing the leaf in sulphuric 

 ether for a few seconds, allowing the fluid to e vaporate,and 

 then mounting it dry. Dr. Inman of Liverpool suggests the 

 following method : " First peel off the epidermis from the 

 petal, which may be done by making an incision through 

 it at the end of the leaf, and then tear it forwards by 

 the forceps. This is then arranged on a slip of glass, and 

 allowed to dry ; when dry, it adheres to the glass. Place 

 on it a little Canada balsam diluted with turpentine, and 

 boil it for an Instant over the spirit-lamp ; this blisters it 

 but does not remove the colour ; then cover it with a thin 

 slip of glass, to preserve it. Many cells will be found 

 showing the mamilla very distinctly, and the hairs sur- 

 rounding its base, each being slightly curved and pointed 

 towards the apex of the mamilla. It is these hairs and the 

 tuamilla which give the velvety appearance to the petal/' 



Fibro- cellular tissue is found readily in Sphagnum or 



