170 MUTATION 



nean fowl, at a time long before records were 

 kept. Again we find that human albinos appear 

 suddenly, complete, and breed true like real spe- 

 cies. We have other cases of semi-albinos of 

 which the history is known. The blue-green 

 Austrahan parakeets were first brought to Eu- 

 rope in 1831. In 1872 an expert records seeing 

 a single yellow specimen, and by 1877 they had 

 become relatively common in Germany, since 

 they breed true, and now they may be found in 

 most bird-stores of our cities. This yellow par- 

 akeet has lost the power of forming black pig- 

 ment, and the new character appeared suddenly 

 and completely. There is every reason for be- 

 heving that the yellow canary was thus derived 

 from the green canary, the white Java sparrow 

 from the gray form, and the albino fowl from a 

 pigmented ancestor. The sudden origin of color 

 changes is generally admitted by breeders and 

 field naturalists; and many more cases of sud- 

 denly appearing characters might be cited, such 

 as hornlessness in cattle, sheep, and goats; tail- 

 lessness in cats, dogs, and poultry ; hairlessness in 

 horses, cows, and dogs; spinelessness and hair- 

 lessness in vegetative organs and fruits; fascia- 

 tion of the stem and pelorism of the leaves and 

 petals of many plants, and extra digits in poul- 

 try, swine, horses, and man. These are examples, 

 merely, for since man first began to domesticate 

 plants and animals hundreds of new characters 

 have appeared suddenly and completely and ca- 



