THE PLANT-CELL. 



1? 



examples of large cells are found in the-Thallophytes ; Nitella, 

 for example, has cells 50 mm. (2 inches) long, and 1 mm. 

 (.04 inch) thick. According to Von Mohl, the bast-cells 

 of a species of palm (Astrocaryuvi) are from 3.6 to 5.6 mm. 

 (.13 to .21 inch) in length. For ordinary plants the average 

 size of the cells may be given as from .1 to .02 mm. (.004 to 

 .0008 inch). From this average size the dimensions of cells 

 decrease to exceedingly small magnitudes. In the Yeast 

 Plant (Saccharomyces cerevisice) the cells are about .008 mm. 

 (.0003 inch) in diameter. The cells of Bacterium termo are 

 from .0021 to .0028 mm. long and from .0028 to .0005 mm. 

 broad (.0001-. 00008 by .00008-. 00002 inch). 



The following table, taken from Hofmeister's " Lehre von der Pflan- 

 zenzelle," is useful as showing how the dimensions of similar cells 

 vary in different plants : 



TABLE OF DIMENSIONS OF VARIOUS KINDS OF CELLS OF WOODY 



PLANTS. 



(In decimals of a millimetre.) 



