THE PAGE OF NATURE. 203 



forms and contents for the performance of particular 

 functions in the economy of the plant. In the fungi, 

 however, there is little or nothing of this specializing or 

 differentiating process. Their entire structure is uni- 

 form ; each group of cells is an exact repetition of all 

 the other cells ; one part of each is exactly like the 

 rest. There are no special organs or vessels for the 

 performance of the processes of absorption and reproduc- 

 tion, no complicated apparatus of secretion and excretion. 

 There are no leaves, stems, or roots. Every cell is an 

 assimilating surface ; the whole plant is a reproductive 

 organ. Every part of the structure performs the func- 

 tions, which in more complex plants are performed by 

 organs specially set apart. 



Owing to this extreme simplicity and unity of struc- 

 ture, they possess a remarkable power of reproducing 

 and repairing such parts of their substance as have been 

 injured. This power, it is well known, is always more 

 active as the organization of the individual, or the part 

 affected, is less complicated ; many of the simplest 

 animals, such as the polypes, admitting of being multi- 

 plied by mere mechanical division almost to an un- 

 limited extent. It has been often remarked, that in 

 man and the vertebrata generally, the power of regenera- 

 tion is confined to the replacement of small portions of 

 the simplest texture, although in them the process of 

 renewal is sometimes very extraordinary. The more 

 highly organized structures, such as muscular and nervous 

 substance, cannot be replaced ; should they be ruptured, 

 the wound is repaired by the formation of cellular, or 

 some other of the less complex tissues. Every part of the 



