58 BAILEY--MOVEMENT IN PLANT-BREEDING. [April 2, 
other named variety of corn, nor does it propose that any new 
variety shall be created. It suggests what may be done with any 
variety of corn. The experiments in Illinois demonstrate that 
‘*the yield of corn can be increased, and the chemical composition 
of the kernel can be changed as may be desired, either to increase 
or to decrease the protein, the oil, or the starch.” 
The breeding of the corn proceeds along two general lines—for 
physical perfection and for chemical perfection. Selection for 
physical merit proceeds as follows, to quote again from Professor 
Hopkins: ‘‘ The most perfect ears obtainable of the variety of corn 
which it is desired to breed should be selected. These ears’ 
should conform to the desirable standards of this variety and 
should possess the principal properties which belong to perfect 
ears of corn, so far as they are known and as completely as it is 
possible to secure them. These physical characteristics and prop- 
erties include the length, circumference, and shape of the ear and 
of the cob; the number of rows of kernels and the number of ker- 
nels in the row; the weight and color of the grain and of the cob; 
and the size and shape of the kernels. In making this selection 
the breeder may have in his mind a perfect ear of corn and make 
the physical selection of seed ears by simple inspection, or he may 
make absolute counts and measurements and reduce the physical 
selection almost to an exact or mathematical basis.’’ 
The selection for chemical content is made on two bases—on 
the general gross structure of the corn kernel as determined by 
‘mechanical examination,’’ and on chemical analysis of the 
kernel. 
Chemical examination by means of mechanical examination is as 
follows : 
‘“The selection of seed ears for improved chemical composition 
by mechanical examination of the kernels is not only of much 
assistance to the chemist in enabling him to reduce greatly the 
chemical work involved in seed corn selection, but it is of the 
greatest practical value to the ordinary seed corn grower who is 
trying to improve his seed corn with very limited service, if any, 
from the analytical chemist. This chemical selection of seed ears 
by mechanical examination, as well as by chemical analysis (which 
is described below), is based upon two facts: 
‘rz. That the ear of corn is approximately uniform throughout in 
the chemical composition of its kernels. 
. 
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