154 PLANT-BREEDING 



for oil content may be made by the choice of ears with the 

 largest germs, and for protein by the selection of ears with a 

 well developed horny endosperm, or, since the white starch 

 is more striking to the eye, with a lesser development of this 

 tissue, which is poor in protein. This deduction has been 

 confirmed by the brilliant discoveries of C. G. Hopkins, of 

 the University of Illinois, by chemical analysis as well as 

 by direct breeding experiments. In the year 1896, he began 

 the breeding of corn with the idea of changing its chemical 

 contents in an experimental way, and selected seed of 

 white Illinois corn for four different purposes: High and 

 low oil content and high and low protein production. In 

 the year 1903 he had succeeded in isolating four different 

 races, the average values of which differed greatly from 

 that of the variety from which he started. The ears with 

 the extreme percentage of these substances have been picked 

 out by a chemical analysis of* two longitudinal rows of 

 kernels for each ear, but their breeding ability has had to 

 be studied in their progeny by the row-system, as described 

 above. The result was the isolation of high and low oil 

 races, which averaged 6.96 and 2.62 per cent, and of high 

 and low protein races containing 14.13 and 6.98 per cent. 

 It is evident that by these most remarkable experiments the 

 possibilities of the breeding of corn for special purposes has 

 been demonstrated, and the value of this fact for large in- 

 dustrial concerns can hardly be overestimated. 



For experimental tests and commercial purposes the dif- 

 ferent parts of the kernels can be more or less accurately 

 separated. This is done by softening them in water and 

 then passing them into mills. First the hull is removed, the 

 germ is freed and the starch body broken up. Water being 

 used, the germs, which are lighter in weight, rise to the 

 surface and are separated. The remaining mass is once 

 more milled or ground and brought into a very fine condi- 



