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 
Cell 
