THE PROTOPLAST 



13 





*f- 



FIG. 27. FRUIT or THE COTTON-PLANT 



(Gossypium). 

 Jach of the soft hairs of the cotton is a single cell 



contains more than a million cells, and 

 that there are one billion two hundred 

 million in a cubic inch ; but the state- 

 ment by itself has little or no value 

 from a scientific point of view. When, 

 however, we are told (what neither 

 Hooke nor Leuwenhoek, nor any of 

 the older microscopists could have 

 told us) that each of these one billion 

 two hundred million cells originated 

 in a tiny speck of protoplasm, which, 

 after forming for itself aye. and/rom 

 itself as our little zoospore had done, 

 a delicate cell-wall, finer a thousand 

 times than the finest gossamer, had 

 proceeded to spread upon the interior 

 of that cell-wall layer after layer of 

 a new 

 sub- 

 stance, 

 w h i c h 



we re- 

 cognise as suberin or cork, till the " little 

 box " was almost filled up when these facts 

 were added, it may be said that our know- 

 ledge had indeed made great advances. 



As allusion has been made to the wonder- 

 ful minuteness of the cells of cork (fig. 30), 

 it may not- be out of place to add a few 

 remarks on the comparative sizes of cells, 

 before we pass on to the consideration of 

 living matter or protoplasm. All cells, with 

 but few exceptions, are microscopically small ; 

 mere specks, indeed, and quite invisible to 

 the naked eye. If the task were proposed 

 to us of counting the honeycomb-like par- 

 titions in a thin section of the stem of a 

 lily, or the twig of an apple-tree, or a shred 

 of cucumber, or the petal of a rose and 

 these delicate partitions are so many cells 

 we should certainly beg to be excused : 

 for the microscope reveals the fact that they 

 are of such minuteness that many thousands 

 might lie, side by side and end to end, on 



FIG. 28. Vaucheria clavata. 



A plant of a single cell, which is drawn out 

 into a tubular form. 



