HEREDITY 97 



nothing but blacks, and similarly the whites can give 

 nothing but whites; while the grays, having the same 

 constitution as their gray parents, when bred together 

 give the same results. 



It is not always the case, however, that the character- 

 istics of the parents produce an appearance of blending 

 in the offspring as in the case of the gray Andalusian fowl 

 bred from a black and a white parent. If for instance we 

 cross a red Antirrhinum (Snap-dragon) with a white one, 

 the hybrids are not pink, but as red as the red parent. 

 If we breed together two of these hybrid reds, or take 

 seed from such a plant fertilized by its own pollen, we 

 get red and white offspring in the proportions of three 

 reds to one white. Further breeding shows that these 

 whites bred together produce only white offspring, while 

 the reds are of two kinds. Out of every three reds there 

 is one which is incapable of giving any but red offspring, 

 and two which show themselves to be of the same com- 

 position as their hybrid red parent, giving mixed offspring 

 in the proportion of three reds to one white. 



The fact that the hybrid red, though indistinguishable 

 superficially from the pure red, gives a proportion of 

 whites among its offspring, shows that the characteristic 

 of whiteness is present, though concealed. In such 

 cases the characteristic which is concealed is called 

 recessive, while the stronger characteristic which alone 

 makes its appearance is known as dominant. 



A glance at Fig. 48 will show the relation of this result 

 to the case of the Andalusian fowl. Supposing that 

 black were dominant over white instead of blending with 

 it, all the grays would appear as blacks, and the pedigree 

 would read as follows : Line 2 hybrid black ; line 3 

 three blacks (i.e. one pure black and two hybrid blacks), 



