122 DOMESTICATED ANIMALS AND PLANTS 



the animal is not in the environment, but is inherent in the 

 organism, the development being influenced but not determined 

 by the conditions of life. 



This particular nature which makes corn to be corn and not 

 wheat, and wheat to be wheat and not barley, — this particular 

 nature was implanted by the ancestry and will be transmitted to 

 the descendants, in varying degrees perhaps, but yet true to 

 nature if not absolutely true to type ; that is to say, the descend- 

 ants of corn will be corn and not wheat, for, as we have already 

 noted, every individual will transmit all the characters of his 

 race and no others. 



The machinery of transmission. How, now, is this effected ? 

 How can the particular traits or unit characters that distinguish 

 corn from wheat, or perhaps one kind of corn from another, — how 

 can these specific differences, sometimes slight, be carried over 

 and appear again with more or less exactness in the offspring ? 



To one accustomed to seeing everything producing after its 

 kind, it all seems very natural, not to say inevitable, that this 

 should be so ; but the more the matter is studied the more 

 difficult it becomes, and no subject in the realm of living 

 matter is to-day giving scientists more trouble than this very 

 one of transmission. 



Whoever will take the trouble to visit a cornfield just after 

 it is coming into tassel will have the opportunity of observing 

 nature at work about some of its most important business. 



First of all, he will see the embryo ear about halfway up the 

 stalk, with a long fringe of tender V silk " pushing out from the 

 end and after a time growing longer and dangling in the wind. 

 If now the husks be carefully stripped down, the embryo cob 

 will be discovered, and it will be found that each particular silk 

 runs down and is attached separately and independently to a 

 definite spot, which will one day, if all goes well, become a new 

 kernel of corn. 



Now, if all does go well, the silk will, after a few days, wither 

 away, the spot on the cob at its base will begin to grow, and will 



