3SI4. APPENDIX 



breeder works his will, and on his skill in wielding them 

 depends his success or failure. 



In captivity, under the best conditions, heredity and selec- 

 tion assume major positions, the proper development of 

 the individual and suitable surroundings being matters of 

 more simple routine. 



Heredity is the force which is of greatest importance to 

 the breeder, for it is on the workings of its laws that the 

 result of his efforts depends. The saying that " like pro- 

 duces like " is well known, but if it were entirely true 

 progressive breeding would not be possible. Like produces 

 like in a general way, but no two individuals ever are 

 identical. It is here that the breeder finds leverage to 

 sway the character of his subjects. An understanding of 

 the laws of heredity and the methods of making use of 

 them, so far as they have been made known, are essential 

 to success in animal culture. 



Heredity is commonly considered to concern the inherit- 

 ance of parental characters by the offspring. This is true 

 in a sense, of course, but the true meaning is really much 

 more comprehensive. In the narrow definition the " pull " 

 of the total number of ancestors, which is the governing 

 influence, is lost sight of, an error which has brought to 

 grief many a budding amateur. 



The effect of the ancestors on hereditary characters has 

 been expressed numerically by Galton.* According to his 

 theory, the immediate parents contribute between them one- 

 half the heritage, the grandparents one-fourth, the great- 

 grandparents one-eighth, etc., the fraction decreasing with 

 each backward step. Thus each individual parent has but 

 one-fourth the total, each grandparent one-sixteenth, and 

 each great-grandparent but one-sixty-fourth, so that the in- 

 fluence of ancestors diminishes rapidly. In the sixth gen- 



* Galton, Francis: Natural Inheritance, pp. 134-137. 



