324 THE PHENOMENON OF 



effected by reproduction, and the circle of Varieties which 

 come into existence in the course of reproduction; but 

 the flora of the ancient world,* and the geographical 

 distribution of the plants of the present epoch, f afford us 

 important indices at least, pointing to the connection in 

 time and space of the history of development of the 

 Vegetable Kingdom as a whole and in its parts. 



We have examined Rejuvenescence in general and 

 more particularly in the processes of Vegetable life, and 

 rising from the narrower circle of the development of the 

 single being, we have sought for it again in the wider 

 circles of the Organism of Nature, and in this way arrived 

 at the conviction, that it lies at the foundation of all sub- 

 division in life, all graduated development; that it is 

 this, through which not only the single being progresses 

 from one formation to another, but the whole chain of 

 being is carried onward from generation to generation ; 

 through which the smallest step of the organic structure 

 is introduced, the greatest transitions of Nature carried 

 into effect, and the metamorphosis in the individual, like 

 the transformation of Nature as a whole from age to age, 

 brought about. At the conclusion, then, of our reflec- 

 tions, the question will not appear premature, if we ask, 

 What property of life it really is which declares itself in 

 the Phenomenon of Rejuvenescence ? In the first place, a 

 general acknowledgment must be made that the orderly 

 succession of phenomena of Rejuvenescence, which pre- 

 sents itself to us in every natural development, cannot be 

 explained through the effort of external natural forces, 

 but points to an internal cause. Every train of develop- 

 ment exhibits in its course an adherence to plan which 



* See pp. 7 9. The law of development becomes more and more 

 evident in the newer works on the character of the vegetable kingdom iu 

 ancient epochs. See, in reference to this, the latest comparative view by 

 Ad. Brongniart, in his ' Tableau des genres de Veget. Fossiles,' p. 93, (1849.) 



t Note, for example, the native country of the family of Cactese, the 

 cactus-like Euphorbise, the Epacridese, the group of the Heliophilese in the 

 family of the Cruciferse, the rich genera Stapelia, Pelargonium, Aloe, Agave, 



