56 EXPERIMENTAL EVOLUTION LECT. 



granules are more numerous in the flowers from high 

 altitudes. C. Flahault's 1 experiments are more con- 

 clusive, and the conditions under which they have 

 been performed are more satisfactory. His experi- 

 ments have been made on plants grown in Upsala 

 and in Paris from seeds of same origin. One half of 

 the Parisian seed has been sown in Paris, and the 

 other in Upsala ; one half of .the Upsala seed has 

 been sown in Paris, and the other in Upsala. With 

 the two experiments the result has been the same, the 

 flowers have always been more vividly coloured in 

 Upsala than in Paris, and the same holds good when 

 flowers of plants spontaneously growing around Paris 

 and around Upsala are compared. In some cases, 

 however, there is but a very slight difference. M. 

 Flahault has had the exact colours represented in his 

 paper, and the comparison of the Upsala and Paris 

 flowers is thus shown to the reader as if he had the 

 flowers themselves. 



Concerning colour variation in animals, I must be 

 content with calling attention to some principal facts. 

 One is, that while animals in their natural wild 

 state offer but very slight colour variations in the same 

 region, these variations become very numerous under 



1 Nonvelles Observations sur les Modifications des Vegetanx suivant 

 les Conditions physiques du Milieii. Annales des Sci. Nat. (Bot.) t. ix. 

 1880, p. 159. 



