I 



VI 

 BOTANY 



end of the nineteenth century marked 

 something more than a formal turning- 

 point in the history of science. The 

 dawn of the twentieth century was ushered in with 

 a real renaissance in scientific discovery, both in 

 the biological and the physical sciences. In the 

 latter part of the Victorian period scientific re- 

 search seemed to have reached a point at which 

 all the main outlines of the picture had been 

 sketched, and it only remained to fill in the details. 

 In physics, as Professor Richardson has reminded 

 us, it was suggested that future discoveries were 

 to be looked for in the third place of decimals, 

 with the inference that their importance in the 

 scheme of things was to be gauged by the minute- 

 ness of their size. In biology, the Darwinian 

 conceptions of natural selection and adaptation 

 were regarded as the last word in evolution, and 

 naturalists were busily occupied in showing to 

 their satisfaction how all the known cases of 

 adaptation and differentiation of species could be 

 accounted for on the principles enunciated nearly 

 forty years earlier by Darwin. 



