58 EVOLUTION 



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Atlantis,' that far-sighted Utopia of sci- 

 ence which has already been so largely 

 realized, Bacon suggested that experiments 

 should be set agoing in order to discover how 

 far surroundings can affect and transform 

 living creatures; and many naturalists have 

 dreamed of and pleaded for such an Institute 

 of Experimental Evolution. One such has 

 lately been founded in the United States, 

 the precursor, it is to be hoped, of many in 

 Europe. " Since Nature, ' said Isidore 

 Geoff roy Saint-Hilaire, "left to herself never 

 allows us to witness modifications of much 

 magnitude in the conditions of life, it is clear 

 that only one way is open to us if we wish to 

 perceive such modifications and to examine 

 their effects on the organism; we must oblige 

 Nature to perform that which she would not 

 spontaneously accomplish." Good exposi- 

 tions of the results of various sets of experi- 

 ments will be found in H. De Varigny's 

 'Experimental Evolution" (1892), and more 

 recently in T. H. Morgan's "Experimental 

 Zoology' (1907); and we cannot here do 

 more than give a few typical illustrations. 

 In a few cases it has been found possible 

 to induce experimentally what may be called 

 an adaptive response. Thus Professor Poul- 

 ton's beautiful experiments on the pupa? of 

 certain butterflies show that the colour of 



