314 Evohition and Adaptatioii 



Scotch rose, it is known that the new variations only appeared 

 after a time. The following statement by Salter is then 

 quoted, " Every one knows that the chief difficulty is in 

 breaking through the original form and color of the species, 

 and every one will be on the lookout for any natural sport, 

 either from seed or branch ; that being once obtained, how- 

 ever trifling the change may be, the result depends on him- 

 self." Jonghe is also quoted to the effect that " there is 

 another principle, namely, that the more a type has entered 

 into a state of variation, the greater is the tendency to con- 

 tinue doing so, and the more it has varied from the original 

 type, the more is it disposed to vary still further." Darwin 

 also quotes with approval the opinion of the most celebrated 

 horticulturist of France, Vilmorin, who maintained that "when 

 any particular variation is desired, the first step is to get the 

 plant to vary in any manner whatever, and to go on select- 

 ing the most variable individuals, even though they vary in 

 the wrong direction ; for the fixed character of the species 

 being once broken, the desired variation will sooner or later 

 appear." 



Darwin also cites a few cases where animals have changed 

 quite quickly when brought under domestication. Turkeys 

 raised from the eggs of wild species lose their metallic tints, 

 and become spotted with white in the third generation. Wild 

 ducks lose their true plumage after a few generations. " The 

 white collar around the neck of the mallard becomes much 

 broader and more irregular, and white feathers appear in 

 the duckling's wings. They increase also in size of body." 

 In these cases it appears that several generations were 

 necessary in order to bring about a marked change in the 

 original type, but the Australian dingoes, bred in the Zoo- 

 logical Gardens, produced puppies which were in the first 

 generation marked with white and other colors. 



The following cases from De Varigny are also very striking. 

 The dwarf trees from Japan, for the most part conifers, which 



