280 AGRICULTURAL CHEMISTRY 



per cent, protein and winter wheat 1 1.8 per cent. In 

 both spring and winter wheat, variations in protein from 

 8 to 1 6 per cent, are noticeable. While average wheat 

 contains 12.5 per cent., some samples contain as low as 8 

 and others as high as 18 per cent. 



The greatest differences in composition are noticeable 

 when wheat grown at different seasons is compared. 

 Five samples of the 1891 crop of wheat analyzed by the 

 Minnesota Experiment Station contained 12.01 percent. 

 of protein. The wheat was of unusually high milling 

 and baking value. In 1892, six samples from the same 

 localities showed 13.22 per cent, of protein, and in 1901, 

 14 samples contained 15.21 per cent. 



Some of the effects of climate and soil upon the phys- 

 ical and chemical properties of wheat are noted in Bulletin 

 No. 1 8, Part 9, Division of Chemistry, U. S. Department 

 of Agriculture, from which the following paragraphs are 

 taken : 



" The inherent tendency to change which is found in 

 all grains is most prominent in wheat ; it may be fostered 

 by selection and by modifying such of the conditions of 

 environment as it is in the power of man to effect. The 

 most powerful element to contend with is the character 

 of the season or unfavorable climatic conditions. The 

 injury done in this way is well illustrated in Colorado, 

 and it would seem advisable in such cases to seek seed 

 from a source where everything has been favorable, and 

 begin selection again. It must be borne in mind that 

 selection must be kept up continuously, and that rever- 

 sion takes place more easily than improvement. It took 



