468 POULTRY CULTURE 



to recede in the race if not interfered with ; that is the natural 

 status of such characters. The breeder, who works as far as pos- 

 sible with predominant characters, considers a character which has 

 once disappeared and may reappear, latent. As a rule, his only 

 interest in it is to prevent, as far as possible, its reappearance. The 

 reappearance of latent characters after a lapse of one generation 

 is called alternate inheritajice. The reappearance of characters 

 after a lapse of two or more generations, but still traceable to 

 comparatively near ancestors, is called reversion. The appearance 

 of a character not belonging to the race as it exists, or to its 

 known ancestors, but presumed to be derived from a very remote 

 ancestor, is called atavism. 



From the occurrence of the phenomena of alternate inheritance, 

 reversion, and atavism we conclude that the germ contains possibil- 

 ities of development of any character of any ancestor, however re- 

 mote ; by the regularly diminishing frequency of the occurrence of 

 a recessive character, as the number of generations of ancestors 

 free from it increases, we conclude that, once eliminated from a 

 single individual, a family, strain, or variety, practically free from 

 that character, may be produced in three or four generations. 



Laws of heredity. A general law of inheritance may be based 

 on the rate of increase of a dominant character in a race, or on 

 the decreasing reappearance of a recessive character. The law as 

 worked out by Galton, from the investigation of inheritance in 

 human beings, is generally accepted by poultry breeders as a 

 correct expression of the general behavior of characters of poultry 

 in reproduction, and as showing approximately the percentage in 

 each generation of birds which show a selected character com- 

 mon to all observed ancestors, or a rejected character absent in 

 all observed ancestors. 



Galton's law. An individual inherits from each of its two 

 parents of the first generation, \ of its total characters ; from each 

 of its four parents of the second generation, ^-^ ; from each of its 

 eight parents of the third generation, g^^ ; from each of its sixteen 

 parents of the fourth generation, g^g ! ^^'^ ^'^'^ ^^ i^s thirty-two 

 parents of the fifth generation, ^-^^^, and so on. 



Applied to a single character appearing in an individual but not 

 present in other members of the race, this means that one fourth 



