n8 COMMON MODES OF INHERITANCE 



" Blue eyes are due to the absence of brown pigment. If 

 there is a determiner for brown pigment in the germ-plasm, it 

 will produce such pigment in the body that arises from that 

 germ-plasm. The absence of iris pigment is proof of the absence 

 of the pigment determiner from the germ plasm. If both parents 

 lack brown pigment, their offspring, being devoid of the deter- 

 miner for brown pigment, will all lack brown pigment. As a 

 matter of experience two parents with pure blue eyes will have 

 only blue-eyed offspring." 



