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. 



The spiral and other vessels of plants require to be 

 dissected out under a simple magnifying-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 

 •vater until mounted. 



Vascular tissue requires both maceration and dissection 

 for its separation. The cuticle or external covering of 

 plants is a highly interesting structure ; it is best seen in the 

 pelargonium, oleander, &c. ; and may be mounted dry 01 

 in Canada balsam. 



Cellular tissue is best seen in fine sections from the pith 

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

 are mostly composed of cellular tissue, and their brilliant 

 colours arise from the fluid contained within 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 very interesting. The petal of 

 the geranium is one of the most beautiful objects 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 evaporate, and then putting 

 it up dry. Dr. Inman of Liverpool suggests the following 

 method : " First peel off the epidermis from the petal, which 

 may be readily done by making an incision through it at 

 the end of the leaf, and then tearing 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 

 mamilla which give the velvety appearance to the petal." 



Fibro-cellular tissue is found readily in Sphagnum or 



