6 Pearl and Bartlett. 



sorted into the four different kinds found on each ear. From each of 

 the four lots so obtained random samples of about a pint of kernels 

 each were withdrawn to furnish the material for the chemical analyses 

 of the Fg generation. Samples of the P and Fj generations were drawn 

 at random from large supplies of thoroughly mixed seed of these 

 generations which were on hand for other purposes. All of the com 

 used in the chemical work was entirely mature and thoroughly air dried. 

 It remains now to speak of the chemical methods used in this 

 study. The following determinations were made, in duplicate, for each 

 sample after it had been finely ground: i. moisture, 2. nitrogen, 

 3. protein {= N x 6,25), 4. crude fat (ether extract), 5. ash, 9. crude 

 fiber, 7. pentosans, 8. sucrose, 9. dextrose, 10. total sugars, 11. starch. 

 The methods of analysis used were those of the Association of Official 

 Agricultural Chemists (4), except that for the determination of sugars 

 the methods employed by Straughn and Church (5, p. 14) in their 

 study of the effect of environment on the composition of sweet corn 

 were used. These latter methods had previously been worked out by 

 Straughn (6) and published in an earlier paper. The actual work of 

 analysis was carried out by Mr. A. G. Durgin, Assistant Chemist. 



Data. 



The results of the analyses of the parent races and the F^ and 

 F2 cross-bred progeny are given in Tables I und II. Table I gives 

 the percentage of the different constituents actually found, and Table II 

 gives the percentage which each constituent is of the total dry matter. 

 In Table I the figures for each of the duplicate analyses and the 

 arithmetical average of the two are given. In Table II only the 

 averages appear. 



Before entering upon any discussion of the inheritance of these 

 chemical characters it is necessary to compare the analyses of the 

 parent strains used with other published analyses of dent and sweet 

 maize. Two points need specially to be considered here. In the first 

 place, since the whole of the discussion which follows assumes the 

 substantial accuracy of the chemical analyses made, it is desirable to 

 see whether our results agree with those of other workers, on similar 

 material. In the second place it is important to know how far the 

 dent and sweet varieties used in this study as original parent forms, 

 are t5^ical in respect to chemical composition when compared with 

 dent and sweet corn in general. In other words, do the obvious 



