22 THE MICROSCOPE. Feb., 



by a sharp plane, cut it into a neat little square, say 

 one-quarter of an inch, wet it with turpentine, in order 

 to drive out the air, also rendering it transparent, then 

 immerse it in prepared balsam, putting it on a slide, and 

 slipping on a cover-glass, he will have a most beautiful 

 section showing the long cells with the lenticular mark- 

 ings or bordered pits, if it be from one of the pines or its 

 relatives. He can see how nature employs the medullary 

 rays, diverging from the pith to the bark, as the woof. 

 with the warp or vertical woody tissue, in order to vveave 

 that network of ligneous cells combining flexibility with 

 strength. A section of redwood shows the horizontal 

 cells gorged with brilliant ruby-colored resin. A few 

 years ago, I noticed on an apple box a narrow board 

 showing successively the colors, white, cream, yellow, 

 red and brown, all in a width of half an inch. I still 

 have the shaving, mounted, and it is pretty, indeed, to 

 observe how the resin cells increase in number and depth 

 of color, thus giving this California cedar its deserved 

 name of redwood. 



The pappus from the dandelion is very easy to mount 

 and is well worth the time. On a clean slide describe a 

 circle a little smaller than your cover-glass, say seven- 

 sixteenths of an inch in diameter, using a turn-table and 

 employing a small camel's hair pencil wet with colorless 

 balsam. In the central space, which is dry, put a seed 

 or pappus of any small compositse, cover it, pressing 

 down the glass gently ; it will then adhere to the first 

 ring. When dry, ring again on the outside edge with 

 colorless balsam. You will have a delicately beautiful 

 slide — and one to be proud of — mounted in air, as the 

 microscopists say. 



The Chinese shavings sold in the shops make an ideal 

 longitudinal section all ready to mount. The epidermis 

 of any leaf shows the stomata or breathing pores, if 

 simply wet with alcohol, then turpentine, and lastly, 



