INHERITANCE IN RACE HORSES 75 



are the carriers of the qualities which one genera- 

 tion transmits to another. Now the most essential 

 feature of the Mendelian conception of inheritance, 

 is that of any pair of alternative characters, such as 

 bay and chestnut colours, each sex-cell can carry 

 only one of the pair. 



It does not carry both of them blended together, 

 like wine and water, nor mixed like oil and water. 

 The two characters are regarded as being carried 

 in different sex-cells. If, therefore, a given horse 

 carries only chestnut colour, all its sex-cells will 

 carry that colour — or rather the factors which when 

 present in the body cells produce that colour. But 

 if it carries both bay and chestnut, then one-half of 

 the sex-cells of the individual will carry the one 

 colour, and the other half will carry the other 

 colour. 



If we remember that every individual is the 

 product of the fusion of two sex-cells, one being 

 derived from a mother and the other from a 

 father, we must regard each of them as a sort of 

 double mechanism with regard to every one of the 

 characters that make up its body. It is, for 

 instance, a bay colour because its bayness has come 

 from the sex-cells of both father, and mother, or 

 because it came from one only, the sex-cell of the 

 other parent contributing chestnutness, which is 

 not manifested if bay is already present in the 

 body cells. 



Now, we may symbolise these facts and concej)- 

 tions by calling the bay colour a dominant character 



