346 J- ARTHUR HARRIS 



Thus while in each stage the larger individuals have the larger heads, 

 the relationships between the total length of the body and the proportional 

 length of the head changes greatly during development. 



Illustration 8. Relationship between total solids and sucrose content 

 in the juice of sugar beets 



Sucrose content of the juice of the sugar beet has been one of the 

 classic examples of variation in text-books on genetics. Nevertheless 

 our knowledge of the problems are, as indicated by a recent review 

 .(HARRIS 1917 b), far from complete. Relatively little is known, for 

 example, of the correlation between total solids and sucrose content. 

 Yet this problem is not merely of physiological and genetical interest 

 but of very great practical importance as well, since the coefficient of 

 purity of the juice is an important factor in sugar manufacture. 



Table 4 shows the correlation between total solids and sucrose con 

 tent in 475 Nevada sugar beets. Nominally this series is composed of a 

 number of commercial varieties, but since it has been shown elsewhere 

 (HARRIS and GORTNER 1913) that the correlation between weight and 

 composition of juice is not greatly influenced by the combination of these 

 nominal varieties, such heterogeneity as exists probably does not influ 

 ence materially the correlations to be deduced. For purposes of compari 

 son the constants for a series of 61 determinations from Washington 

 are added. 



The Nevada series gives : 

 For total solids, 



Mean = 18.021, a = 3.7224, CV = 20.656 

 For sucrose, 



Mean = 14.989, a = 4.0727, CV = 27.171 

 For total solids and sucrose, 



r = .882 .007 



For total solids and deviation of sucrose from its probable value, 

 r n = + .251 .029 



For the Washington series the results are: 

 For total solids, 



Mean = 16.445, a = 1-5896, CV = 9.666 

 For sucrose, 



Mean = 11.838, a = 1.9098, CV = 16.133 

 For total solids and sucrose, 



r = .866 .022 



