2 STRUCTURE OF 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 much enlarged. C, a scale in vertical section. In 

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

 wall; ep., epidermis ; N, nucleus ; n, 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 



