THE PAGE OF NATURE. 129 



But how is it, it may be asked, that process meets 

 process in two contiguous filaments, and form between 

 them a germinating spore 1 By what power is a plant 

 given to understand, that a similar plant lies in its im- 

 mediate neighbourhood, ready to carry on the necessary 

 fructifying process 1 Certainly we can consider it no- 

 thing l^&"than a species of the same indefinable opera- 

 tion, which prompts the bee to construct a cell of an 

 hexagonal form, or a bird to build a nest in the manner 

 peculiar to its species. 



We thus find that these obscure plants form no 

 exception to the very general, if not universal law, 

 that each species of living being requires two distinct 

 elements for its perpetuation. Sexual elements have 

 been detected in most of the cryptogamic plants, and 

 in a short time will probably be discovered in all. 

 The power of reproduction by segmentation, or the pro- 

 duction of numerous successions of asexual fertile gene- 

 rations, which, in common with many others of the 

 humblest organisms, vegetable and animal, the confervse 

 possess, is in all cases limited, the species necessarily re- 

 verting to sexual admixture for its perpetuation. The 

 germs produced by the conjugation of approximated in- 

 dividuals, when fully ripe, burst the cells in which they 

 are confined, and are consigned to the surrounding water, 

 where they float about, until they meet with some sub- 

 stance to which their mucilage enables them to adhere ; 

 and once established in a congenial situation, they spring 

 up into new plants, and extend themselves with amazing 

 rapidity, in a week or two producing thousands and tens 

 of thousands of individuals. Their lives rarely exceed a 



