55X THE HISTORY OF BIOLOGY 



the then newly-discovered cytological details. " Alle Verjungungen im Zellen- 

 leben sind mit einer mehr oder minder tiej eingreifenden Entbildung der bereits be- 

 festigten und der Fortbildung understrebenden Telle der Zelle verbunden.'' By this 

 '^ Entbildung" is meant simply the dissolution of the cell membranes upon 

 the segmenting of the cells, which, of course, represents the "Verjungungs" 

 phenomenon. These same principles are also applied to vegetable geography, 

 and the system becomes merely a link in this magnificent unity whereby 

 "the whole of nature's course of development from the first manifestations 

 of life through an infinite number of rejuvenations gradually rises to the 

 emerging of man." All this speculation is interesting as being an intermedi- 

 ate link between the old natural philosophy in the spirit of Goethe and 

 the new philosophy of Haeckel, who differs from his master only in his 

 materialistic tone, though but little in fact. Haeckel's symmetry ideas in 

 particular are certainly in imitation of Braun. 



Exact research, however, must eventually come into its own even in 

 vegetable morphology. The scientist who has contributed more than anyone 

 else towards producing an exact conception of the forms and development 

 of plant life is Nageli, though even he was in close contact with the old 

 idealistic philosophy. Carl Wilhelm Nageli was born in 1817 near Zurich, 

 where his father was a physician, and it was intended that he should be 

 trained for the same profession at the college in his native town. His at- 

 tendance at the lectures of the aged Oken, however, induced him to take 

 up a more speculative career, which he was finally permitted to do. He 

 studied botany at Geneva under de Candolle and wrote as his dissertation 

 a work on vegetable classification; he then went to Berlin and spent a couple 

 of years studying Hegel's philosophy, which, according to his own state- 

 ment, did not attract him very much, and he finally spent some time working 

 at Jena under Schleiden. He was a friend of Kolliker and accompanied the 

 latter on a trip to Italy, afterwards becoming professor, first at Freiburg, 

 then at Zurich, and ultimately at Munich, where he spent the rest of his 

 life in work of an unusually many-sided and productive character. Since his 

 childhood his health had been poor, but he worked with indomitable en- 

 ergy up to the last ten years of his life, when sickness compelled him to 

 abandon his activities. He died in 1891. Ill health brought with it an 

 irritable temper, which made it difficult to associate with him, either as 

 a teacher or as a man of science; indeed, his personal pupils were few in 

 number, but the influence exercised by his writings was all the greater. In- 

 deed, he must without doubt be counted among the foremost botanists of 

 the century, and that, too, in many different spheres, being at the same time 

 anatomist and cytologist, morphologist and systematist; moreover, his natu- 

 ral-philosophical speculations have proved of deep significance. 



