YOUNGER YEARS OP A PLANT. 163 



gives strength and firmness to the beautiful structure. In 

 some plants this development of new cells goes on slowly ; 

 in others with truly marvellous rapidity, as in one of the 

 fungi, which forms twenty thousand visible cells in a single 

 minute ! 



But the minute, delicate form would be but short-lived, 

 and fall an easy prey to the first rude breath of air, if 

 nature did not here also instil the great lesson, that Union 

 is Strength. That wondrous chemical laboratory, contained 

 in the mysterious* seclusion of each cell, produces next a 

 cement which permeates the walls, and glues cell to cell, 

 so that, hardly developed, they cannot move from the 

 spot, and, though provided w r ith life and strength for long 

 generations, they are still, like Prometheus, bound for ever 

 on the rock of adjoining cells. At the extremities of 

 plants this glue hardens into a thick varnish; it is this 

 material which gives density and mechanical strength to 

 the so-called woody fibres ; it forms the bark of trees 

 and covers the plum with a coating of wax. It appears 

 as a viscid layer on the leaves of water plants, which 

 are thus made slippery to the touch and impermeable to 

 water, or as a blue powder on our cabbage, which can 

 be wholly immersed without being wetted. Only here 

 and there, but even in the hardest and fullest cells, tubes 

 of a spiral form are left open. Some are mere small jail 

 windows, imperceptible to the naked eye, and only lately 

 discovered; but they always meet, in unfailing regularity, 

 with a similar tiny look-out from the neighbor, so that 

 Nature evidently does not seem to approve of solitary con- 

 finement. Others are larger, and serve as air passages; 



