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THE AMERICAN NATURALIST [Vol. XLIIl 



of their being "a variation induced by some unknown 

 cause," and says that "on this view the case is the most 

 remarkable one ever recorded of the abrupt appearance 

 of a new form which so closely resembles a true species 

 that it has deceived one of the most experienced of living 

 ornithologists." In all points this case agrees with the 

 modern idea of a mutation, even in the respect that it 

 comes from a family of birds not usually considered very 

 variable. 



Concerning fowls Mr. Darwin remarks that 



Fanciers, whilst admitting and even overrating- the effects of crossing 

 the various breeds, do not sufficiently regard the probability of the 

 occasional birth, during the course of centuries, of birds with abnormal 

 and hereditary peculiarities. Whenever, in the course of past centuries, 

 a bird appeared with some slight abnormal structure, such as with a 

 lark-like crest on its head, it would probably often have been preserved 

 from that love of novelty which leads some persons in England to keep 

 rumpless fowls and others in India to keep frizzled fowls. And after 

 a time any such abnormal appearance would be carefully preserved from 

 being esteemed a sign of the purity and excellence of the breed; for on 

 this principle the Romans eighteen centuries ago valued the fifth toe 

 and the white ear-lobe in their fowls. 15 



But Mr. Darwin's cases of what we must regard as 

 saltations are not confined to the animal kingdom. We 

 might easily cull from his list numerous more or less 

 pertinent examples under the peach, plum, cherry, grape 

 gooseberry, currant, pear, apple, banana, camellia 

 Crataegus, azalea, hibiscus, althaea, pelargonium, chrysan 

 themum, dianthus, rose and perhaps other plants. Con 

 cerning useful and ornamental trees he says: "All the re 

 corded varieties, as far as I can find out, "have been sud 

 denly produced by one single act of variation," 16 and a 

 to roses, he remarks on their marked tendency to "sport' 

 and to produce varieties "not only by grafting and bud 



