No. 60S] 



NOTES AND LITERATURE 



511 



data are available. There are. furthermore, internal evidences 

 of serious heterogeneity in tlie materials upon which these con- 

 stants are based. Such irregularities as those seen in the fre- 

 quency distributions of number of days required for maturing 

 re(iuirc explanation before coefficients based upon them can be 

 given much weight. 



Tlie ves\\]t of Tritchard's exjieriments which will arouse the 

 widest iiiterest is the .■oiiclusioii that with due regard to the 

 probable ern.r^ of iM;i>lni,i siiuplin-. lliov is lU) correlation be- 



the average pci-ceiitage sug;ii- coiiteiit or tlic average total sugar 

 content of the progeny roots, that there is no correlation between 

 the percentage of sugar in the mother beets and the average 

 percentage of sngar in their progeny, between the actual amount 

 of sugar in the mother beets and the actual amount of sugar 



Thus in dealing with our long selected varieties of sugar 

 beets the author is faced to the conclusion : 



Dif¥ereiires in llic size an.l su-nr cnmcnt ..f in,livi<Iual b.rt roots 

 show no eviden.-o of inluTitniuv. Thoy aiv tluclnal inns. tluMvf.M-o. and 



evident. One European tirm" is said to carry out ;?00.()00 

 analyses annually in the selection of roots for seed production. 

 If the conclusion reached by Pritchard be of final significance. 



Space precluilcN a discussion of the data given by Pritchard 

 on the average (•()ni|)ositi()n of progeny rows and on the influence 

 of environmental factors in observing genetic dilferences. From 

 this side his paper must be read, and will later be reviewed in 

 connection with one on the technical features of progeny tests.^ 



