60 BAILEY—MOVEMENT IN PLANT-BREEDING. [April 2, 
‘¢2, The white, starchy-appearing part occupying the crown end 
of the kernel and usually also immediately surrounding, or partially 
surrounding, the germ. 
«3, The germ itself which occupies the central part of the kernel 
toward the tip end. 
‘‘ These different parts of the corn kernel can be readily recog- 
nized by merely dissecting a single kernel with a pocket-knife, and 
it may be added that this is the only instrument needed by any- 
body in making a chemical selection of seed corn by mechanical 
examination. 
‘‘The horny layer, which usually constitutes about sixty-five per 
cent. of the corn kernel, contains a large proportion of the total 
protein in the kernel. 
‘‘ The white, starchy part constitutes about twenty per cent. of 
the whole kernel, and contains a small proportion of the total pro- 
tein. The germ constitutes only about ten per cent. of the corn 
kernel, but while it is rich in protein, it also contains more than 
eighty-five per cent. of the total oil content of the whole kernel, 
the remainder of the oil being distributed in all the other parts. 
‘¢ By keeping in mind that the horny layer is large in propor- 
tion, and also quite rich in protein, and that the germ, although 
rather small in proportion, is very rich in protein, so that these two 
parts contain a very large proportion of the total protein in the 
corn kernel, it will readily be seen that by selecting ears whose 
kernels contain more than the average proportion of germ and 
horny layer, we are really selecting ears which are above the aver- 
age in their protein content. As a matter of fact, the method is 
even more simple than this, because the white, starchy part is 
approximately the complement of, and varies inversely as, the 
sum of the other constituents ; and to pick out seed corn of high 
protein content it is only necessary to select those ears whose ker- 
nels show a relatively small proportion of the white, starchy part 
surrounding the germ. 
** As more than eighty-five per cent. of the oil in the kernel is 
contained in the germ, it follows that ears of corn are relatively 
high or low in their oil content according as their kernels have a 
larger or smaller proportion of germ. 
‘«In selecting seed.corn by chemical analysis, we remove from the 
individual ear two adjacent rows of kernels as a representative 
sample. ‘This sample is ground and analyzed as completely as may 
