II. 



THE STRUCTURE AND PROPERTIES OF THE CELL. 

 A. General Structure. 



CUT longitudinal sections of a parenchymatous tissue, 

 the young shoot of the Elder, for example, mount in 

 water, examine the parenchymatous cells of the pith 

 with a high power ; 



Note, 1, the Cell-wall, transparent, colourless, and 

 apparently homogeneous ; 



2, the Protoplasm, forming a layer (the pri- 



mordial utricle), closely lining the cell-wall, 

 and connected by bridles with a more 

 centrally placed mass in which 



3, the Nucleus, a well-defined, roundish, 



highly refractive body, is situated ; 



4, the Vacuole, filled with colourless fluid, 



the Cell-sap. 



Structure of the Protoplasm and Nucleus, Harden a 



small piece of a young growing shoot or root of Pinus in picric 

 acid or in absolute alcohol ; stain with ammonia-haematoxylin ; 

 mount in dilute glycerine, or stain with Kleinenberg's hsematoxy- 

 lin, and mount in Canada balsam ; examine with a high power : 



Observe in the protoplasm 



1. The Ectoplasm, a hyaline layer, but little stained, next to 

 the cell- wall. 



