424 HOOKEE'S POSITION AS BOTANIST 



century after Hooker first set foot in India. It is upon sue] 

 foundations that Hooker's reputation as a great constructiv 

 thinker is securely based. 



The first named of these Essays will probably be estimate! 

 as the most notable of them all in the History of Science. I 

 was completed in November 1859, barely a year after th 

 joint communications of Darwin and Wallace to the Linnea] 

 Society, and before the ' Origin of Species ' had appeared. I 

 was to this Essay that Darwin referred when he wrote tha 

 1 Hooker has come round, and will publish his belief soon, 

 But this publication of his belief was not merely an echo c 

 assent to Darwin's own opinions. It was a reasoned statemen 

 advanced upon the basis of his ' own self-thought,' and hi 

 own wide systematic and geographical experience. From thes 

 sources he drew for himself support for the ' hypothesis tha 

 species are derivative, and mutable.' He points out how th 

 natural history of Australia seemed specially suited to tes 

 such a theory, on account of the comparative uniformity of th 

 physical features being accompanied by a great variety in it 

 Flora, and the peculiarity of both its Fauna and Flora a 

 compared with other countries. After the test had been made 

 on the basis of study of some 8000 species, their characters 

 their spread, and their relations to those of other lands, h< 

 concludes decisively in favour of mutability and a doctrini 

 of progression. 



How highly this Essay was esteemed by his contemporarie: 

 is shown by the expressions of Lyell and of Darwin. The forme: 

 writes : 



I have just finished the reading of your splendid Essa] 

 on the Origin of Species, as illustrated by your wide botanica 

 experience, and think it goes far to raise the variety-making 

 hypothesis to the rank of a theory, as accounting for th< 

 manner in which new species enter the world. 



Darwin wrote : 



I have finished your Essay. To my judgment it is b} 

 far the grandest and most interesting essay on subjects o 

 the nature discussed I have ever read. 



