iO4 Heredity and Eugenics 



they were just the opposite, they were antagonistic to each 

 other so that no pure types were produced having red peri- 

 carps and red cobs (Fig. 44). This is an example of a fea- 

 ture which is probably very widespread in the plant world, 

 but of which we at present know little. It is cited for two 

 reasons; first, to show that characters may at one time be 

 antagonistic to each other and at another time coupled 

 together, and second, to show that one is not able to say 

 beforehand whether a manifestation of a character hi 

 several organs is due to one or to several separately 

 inherited factors. 



Leaving out of consideration sex-limited inheritance of 

 which little is known in plants, we have now briefly gone 

 over simple type cases of some of the most important present- 

 day Mendelian knowledge; but we have considered only 

 crosses in which the potential character or characters are 

 present in one parent and absent in the other. At least 

 they behave that way and may reasonably be so interpreted. 

 Such differences between parents are qualitative, but most 

 differences between parents are quantitative and give an 

 apparent blend in the first hybrid generation. Nearly all 

 cases where varieties differ in the size of their organs are 

 of this kind. Can such phenomena be interpreted by 

 Mendelian notation ? I believe they can. One may think 

 of a factor for a character being present in the germ cell 

 not only once but twice or even a greater number of times. 

 If these factors are transmitted independently and are not 

 paired with each other, but each with its own absence, one 

 may very easily interpret size inheritance. For example, 

 when a certain dent variety of maize is crossed with a flint 

 variety as shown in Fig. 45, an intermediate condition is 

 obtained in the first hybrid generation. In the second 



