i8 



INTRODUCTION 



although it is one of the most important parts, and much 

 study is now being given to it, in an endeavor to under- 

 stand it better. 



FIG. 10. Robert Brown (1773-1858). One of the greatest of English 

 botanists. He discovered the nucleus in cells, and also the gymnospermy 

 of Conifers and Cycads. 



(c) The structural elements of a cell may be concisely 

 tabulated as follows: 



Nucleus (nucleoplasm) 



Nuclear membrane 



Nucleolus 

 Cytoplasm 



Limiting membrane 



Vacuoles 



Vacuolar membranes 



Cell-sap 



Other contents (inclusions) 

 Cell-wall 



