The Author's Preface. xi 



purpose, for I came to the conclusion that my book itself 

 may be regarded as a historical fact, and that the kindly 

 and indulgent reader may even be glad to know what one, 

 who has lived wholly in the science and taken an interest 

 in everything in it old and new, thought from fifteen to 

 eighteen years ago of the then reigning theories, repre- 

 senting as he did the view of the majority of his fellow- 

 botanists. 



However, these remarks relate only to two famous 

 writers on the subjects with which this History is con- 

 cerned. If the work had been brought to a close with the 

 year 1850 instead of i860, I should hardly have found it 

 necessary to give them so prominent a position in it. 

 Their names are Charles Darwin and Karl Nageli. I 

 would desire that whoever reads what I have written on 

 Charles Darwin in the present work should consider that 

 it contains a large infusion of youthful enthusiasm still 

 remaining from the year 1859, when the 'Origin of 

 Species' delivered us from the unlucky dogma of con- 

 stancy. Darwin's later writings have not inspired me 

 with the like feeling. So it has been with regard to 

 Nageli. He, like Hugo von Mohl, was one of the first 

 among German botanists who introduced into the study 

 that strict method of thought which had long prevailed in 

 physics, chemistry, and astronomy; but the researches 

 of the last ten or twelve years have unfortunately shown 

 that Nageli's method has been applied to facts which, 

 as facts, were inaccurately observed. Darwin collected 

 innumerable facts from the literature in support of an 

 idea, Nageli applied his strict logic to observations 

 which were in part untrustworthy. The services which 

 each of these men rendered to the science are still 



