VARIATION OF PROTEIN CONTENT OF CORN 



Paper II ^ 



By H. B. Arbuckle and 0. J. Thies, Jr. 



Findings in Paper I 



1. A rapid Kjeldahl method for the determination of nitrogen in 

 corn. 



2. Report of analyses of certain varieties chosen for experiment. 



3. Corn grown in North Carolina, from West Virginia seed, 

 showed lower protein. 



Introduction 



The protein content of corn determines its value as a feed. In- 

 crease of 1% enhances its value approximately ten cents a bushel. 

 Corn is now purchased at so much per bushel. We pay the same price 

 for corn containing 10% protein as we do for a corn containing 8%, 

 whereas the former is worty" twenty cents more as a feed. Coal is 

 now purchased on the basis of its caloric value. Why should not the 

 price of corn be determined by its food value ? 



It has long been known that the protein content of corn varies. 

 What factors control this variation? This is the goal of this investi- 

 gation undertaken in 1920. 



The first paper was read before this Academy at its spring meet- 

 ing, 1922. This paper presents the results of further investigation 

 with particular reference to climate. 



Comments on Findings in Paper I 



Analysts may be interested to know the result of the more careful 

 examination of the Kjeldahl modification employed in previous years. 



For convenience, a brief summary of the method is given. 



A three gram sample of corn, finely ground, is introduced into a 

 Kjeldahl flask, 0.3 gram of copper sulphate, C. P. added, and 25 cc. 

 sulphuric acid with phosphorus pentoxide. After digesting till the 

 material in the flask is well liquefied, which requires from seven to ten 



^ For paper I see this Journal 38: 84. 192'J. 



