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 “ 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 
