Inconstancy of Improved Races 797 



bad years giving 10^, good years from 12^ to 

 14;^ in the average. Extreme instances excelled 

 n^. From that time the practice of the polar- 

 ization of the juice for the estimate of the sugar 

 has rapidly spread throughout Europe, and a 

 definite increase of the average value soon re- 

 sulted This however, often does not exceed 

 14:^, and beets selected in the field for the pur- 

 pose of polarization come up to an average of 

 15 to 16^, varying downward to less than lOi 

 and upward to 20 and 21^, In the main the fig- 

 ures are the same as those of Vilmorin, the 

 range of variability has not been reduced, and 

 higher extremes are not reached. An average 

 increase of 1^ is of great practical importance, 

 and nothing can excel the industry and care dis- 

 played in the improvement of the beet-races. 

 Notwithstanding this a lasting influence has not 

 been exercised; the methods of selection have 

 been improved, and the number of polarized 

 beets has been brought up to some hundred 

 thousands in single factories, but the improve- 

 ment is still as dependent upon continuous selec- 

 tion as it was half a century ago. 



The process is practically very successful, but 

 the support afforded by it to the selection- 

 theory vanishes on critical examination. 



