2 STRUCTURE OE THE PLANT-CELL 



edge, whilst near the centre or against one side is situated a 

 rounded shining body, the nucleus (Fig. i, B, N). 



These cells consist, then, of three parts, the cell-wall (Fig. i, 

 B, C.W.), which is not living and is merely a protective case, 

 the cytoplasm, and the nucleus; the last two constitute the 



Fig. I. — Epidermis of Onion bulb-scale. A, small portion in surface view. 

 B, a single cell mucfi enlarged. C, a scale in vertical section. In 

 A and C the nuclei are shown black. Cy., cytoplasm ; C.ll'., cell- 

 wall; ep., epidermis ; iV, nucleus ; k, nucleolus ; Va., vacuole. 



living part or protoplast, composed of protoplasm. The proto- 

 plasm is probably a very complex mixture of proteins, fatty 

 bodies, etc., composed mainly of the elements _carbon, hydrogen, 

 oxygen, nitrogen, and sulphur (often together with phosphorus, 

 especially in the nucleus). It has somewhat the consistency 



