1 7 6 Morphology under the Doctrine of [BOOK i. 



leaves, the formation of shoots and their ramification, and the 

 different modes of cell-formation, but even palaeontological 

 facts are manifestations of rejuvenescence, which in the sequel 

 puts off the form of an abstract idea, and becomes personified 

 into an active personality, as is seen in page 8 in the expression, 

 ' activity of rejuvenescence.' 



The relation of Braun's views to the question of the con- 

 stancy of species may to some extent appear doubtful ; some 

 utterances of his may be interpreted to admit a transmutation 

 of species accomplished in the course of ages, while others are 

 opposed to this, and it is the latter which appear to be consis- 

 tent with the idealistic position. We read, for instance, at 

 page 9, ' The appearance, as though the like was always repeat- 

 ing itself in nature, is suggested when we glance back from our 

 station in time upon the succession of former epochs. Here 

 we find the real first beginnings of species and genera, and 

 even of orders and classes in the vegetable and animal king- 

 doms ; we see at the same time that more or less thorough 

 transformations are connected with the appearance of the 

 higher grades in the organic kingdom, so that genera and 

 species of the old world disappear, and new ones step into 

 their place. All this change expresses not the mere accident 

 of convulsions, which, while they destroy, at the same time 

 prepare new ground for the prosperity of organic nature, but 

 rather definite laws whose action pervades all the individual 

 detail of the development of organic life.' On the other hand we 

 find at the conclusion of the treatise on polyembryony, written 

 a short time before the appearance of Darwin's memorable 

 work, a sentence which makes the assumption of a transmuta- 

 tion of species appear very doubtful; it says (page 257), 'If 

 we are justified in assuming a general organic connection in 

 the history of development in plant-forms, can we imagine 

 that the type of the Mosses and of the Ferns has come from 

 the Algae, or vice versa, that the Alga-form owes its origin to 

 the Mosses and Ferns ? ' 



