CHAPTER III 

 THE CELL 



19. Historical.-rThe advancement of our knowledge 

 of nature has often depended upon the invention of some 

 new instrument that made possible observations that 

 could not have been made without its aid. The balance 

 did this for chemistry, the telescope for astronomy, the 

 thermometer for medicine. The possibilities for under- 

 standing plant life were more than doubled by the in- 

 vention of thfe compound microscope. By its aid the 

 study of the finer internal structure of plants was made 

 possible. 



20. Robert Hooke. — One of the earliest to employ the 

 microscope in this way was Robert Hooke (1635-1703) 

 of England. He was at first interested in demonstrating 

 the powers of the microscope on various objects. Among 

 them he tried thin sections of cork, and found the cork to 

 be composed of little compartments, which he called 

 cells, since they roughly resembled the cells of a honey- 

 comb. Marcello Malpighi (1674), an Italian, and Nehe- 

 miah Grew, an Englishman (1682), greatly extended the 

 microscopic study of plants, adding so much to our knowl- 

 edge that they are now often referred to as the fathers of ' 

 plant anatomy. 



21. Protoplasm.— At first the attention of botanists 

 was devoted almost exclusively to the walls of these cell- 

 like compartments, and to their shape and arrangement. 



14 



