Objects for the Microscope. 13 



in all, you will probably observe a larger granule, with a 

 lesser one within, or perhaps several lesser ones ; the large 

 granule is the nucleus, the minute inner ones the nucleoli ; 

 they are the supposed origin of new cells, and much that is 

 exceedingly interesting has been written in the works before 

 referred to : ' Mohl on the Vegetable Cell ; ' ' Hofmeister's 

 Die Enstehung des Embryo.' These nuclei are to be 

 observed in pollen-grains, in the hairs of Tradescantia?, or 

 Spidervvort, especially in the pollen of the fir-tree tribe. 



OIL CELLS. 



Cells containing oil are beautiful objects when found as 

 on rose-trees, on the stem of Saxifrage, Geraniums, Col- 

 lomia, Drasena, raised upon delicate stalks, often brightly 

 coloured, or glittering diamond-like in the sunshine.* Some- 

 times the oil cells are sessile, in golden spots upon the back 

 of a black-currant leaf ; or white and silvery in the recesses 

 of a Sage leaf, a leaf of Rue, or Hop, or Mulberry. 



Sometimes these oil cells are internal, as in the rind of 

 an orange, where they are very large and most easily ob- 

 served; also in the leaves of Myrtle and Magnolia, of 

 Hypericum, St. John's wort, so common in woods and 

 hedges : those little dark dots are the oil cells, and trans- 

 parent, if you hold the leaf up against the light, and 

 examine it with a pocket lens. 



HAIES OF PLANTS. 



The hairs of plants will furnish you with abundant ma- 

 terial for study and delight throughout the summer long, 

 and the variety in their form will astonish you. Look at 

 the beautiful bead-like hairs of the Spiderwort a rich 

 purple chain of cells fringing each stamen. White, trans- 

 parent, glittering rows of cells from the flocculent mass of 

 hairs we see on the leaves and stem of the common 

 Groundsel. The common garden Verbena has the mouth 

 of its corolla closed by a dense row of beaded hairs pro- 

 tecting its pistil. I cannot describe more, but look at these. 



* These are called glandular hairs. 



