Acquired Modifications Heritable ? 103 



houses, come to maturity in the short summer 

 of these extremely northern states. It looks 

 very much as if the short season had had a 

 direct effect upon the corn, and the remarkable 

 thing is that such breeds of corn, when taken 

 south again, retain their habit of early ripening 

 more or less completely, as also do their off- 

 spring. On the face of it, it appears as if this 

 were an example of the acquisition of a new 

 character as a result of environmental influ- 

 ences, and that this acquired modification was 

 transmitted to the progeny. When, however, 

 we examine this case more carefuUy, it is very 

 evident that other interpretations are possible. 

 In any field of corn there will be foimd some 

 plants that ripen earher than others. In other 

 words, there is a degree of variabiUty present 

 in this as in other characters. Evidently, as 

 corn is planted farther and farther north, only 

 the seed from plants that mature early can be 

 gathered for planting next year. The late 

 maturing plant would be nipped by the frost 

 and killed, and would leave no seed. One 

 would, therefore, continually get a selection of 



