FIELD CROPS. 353 



gluten lies immediately under the hull, comprises from 8 to 14 per cent of the gr?.in, 

 and is more abundant in the kernels with a high protein content. This part contains 

 from 20 to 25 per cent of protein, and is the richest in this substance of all the parts 

 of the kernel. 



The horny starch, the chief substance in the sides and back of the kernel, com- 

 prises about 45 per cent of ordinary corn, but the percentage is much higher in corn 

 with a high protein content and lower in corn with a low protein content. This 

 part of the kernel is rich in starch, and contains about 10 per cent of protein. Owing 

 to the large proportion of the kernel which it constitutes, it contains a greater total 

 amount of protein than any other part. The white starch, occupying the center of the 

 crown end of the kernel and usually partially surrounding the germ, comprises about 

 25 per cent of the kernel, being less in high-protein corn and greater in low-protein 

 corn. It contains only from 5 to 8 per cent of protein. The germ comprises about 

 11 per cent of the kernel and varies according to the oil content, constituting a larger 

 proportion in high-oil corn and a smaller proportion in low-oil corn. In oil the germ 

 ranges from 35 to 40 per cent, and furnishes from 80 to 85 per cent of the total oil 

 content of the kernel. Corn high in protein is described as containing a large pro- 

 portion of horny gluten and horny starch, and a correspondingly smaller proportion 

 of white starch. In corn of a high protein content the horny parts comprise over 60 

 per cent of the kernel and contain about 80 per cent of the total protein present. 



In 1900 comparison was made between 2 strains of corn bred for 4 years for high 

 oil and low oil content, respectively. The plants representing the 2 strains were 

 grown this season under identical conditions. The results show only an average 

 difference of 1.97 per cent in the oil content and of 0.18 per cent in the protein con- 

 tent. These figures show that there is less than 5 per cent of a perfect correlation 

 between the oil and protein. From these and previous results it is concluded that as 

 the percentage of protein increases in corn, the starch decreases and the oil content 

 remains practically unchanged, and that the selection of high-protein seed corn 

 should be governed by a large proportion of horny parts, and of high-oil seed corn 

 by a large proportion of germ. 



The chemical composition of 4 strains of pedigreed corn compared for high and 

 low protein and high and low oil was determined from samples of 10 ears each 

 taken from the crop of 1902 and representing the seventh generation. The protein 

 content of the low-protein ears varied from 6.36 to 7.9 per cent, with an average of 

 6.71 per cent, while the protein content of the high-protein ears varied from 13.98 to 

 15.01, with an average of 14.44 per cent. The average oil content of the low-protein 

 ears was 4.21 per cent and of the high-protein ears 4.93 per cent. 



A slight correlation was noticed to exist between the average percentages of pro- 

 tein and germ, but there were some marked exceptions. In one case an ear with 

 6.37 percent of protein contained 9.53 per cent of germ, while in another instance an 

 ear with 14.74 per cent of protein contained 9.51 per cent of germ. One of the lowest 

 protein ears with a protein content of 6.48 per cent contained 10.79 percent of germ, 

 while the highest protein ear, with 15.01 per cent of protein, contained only 9.82 per 

 cent of germ. The results of analyses of the low-oil and high-oil ears show an aver- 

 age for the low-oil corn of 2.52 per cent of oil and 9.98 per cent of protein, and for 

 the high-oil ears of 7 per cent of oil and 11.31 per cent of protein. In these figures 

 the slight correlation between oil and protein again becomes apparent, the high-oil 

 corn containing nearly 3 times as much oil as the low-oil corn, but being less than 

 one-seventh richer in protein. A very marked correlation between oil and germ is 

 shown in the results obtained in studying tlie oil and germ in low-oil and high-oil 

 corn. The 10 low-oil ears contained an average of 2.52 per cent of oil and 7.74 per 

 cent of gfcim, and the 10 high-oil ears an average of 7 per cent of oil and 13.84 per 

 cent of germ. 



