172 EXPERIMENTAL EVOLUTION LECT. 



some vegetable species are predominantly cultivated : 

 in India rice, in Europe wheat, in Oceania the taro- 

 plant, and so on. And while little more than nothing is 

 done at the present time to increase our animal re- 

 sources, much is being done every day to cultivate 

 new plants, for food, pleasure, or drugs. But more 

 remains also to be performed, and I doubt whether 

 the hundred or more species which Sir Joseph Hooker 

 pointed out in his Flora Tasmania as being suitable 

 for cultivation, have all been added to those which have 

 been known to mankind since the long-past ages when 

 agriculture began to be evolved. Four centuries have 

 now elapsed since the American continents were dis- 

 covered : how many species have been added to those 

 which were already under cultivation ? Some forty 

 species, among which, it is true, we must include the 

 potato, arrow-root, cinchona, tobacco, tomato, pine- 

 apple, indian-corn ; but are there not many more 

 which it would prove beneficial to cultivate ? But 

 this is the business of the future, and ours is with the 

 past. 1 Many of our cultivated plants differ but 



1 While thus advocating the necessity of turning to a better account 

 the numerous plants which exist and may be, by cultivation, made very 

 profitable to man in one way or another, I perceive that Prof. G. L. 

 Goodale was addressing the American Association for the Advancement 

 of Science on the same topic at the same time. I will merely refer 

 the reader to his very interesting paper published in the American 

 Journal of Science, under the heading : Useful Plants of the Future. 

 Some of the Possibilities of Economic Botany (pp. 271-303), where 



