102 Selection Does Not Lead to Origin of Species. 



simple and precise, especially since the introduction of 

 the use of the polariscope. 



But it is more likely that Vilmorin's figures were 

 too low than that they were too high. 



1874 was the first year in which the method of polari- 

 zation was employed and the selection based on the re- 

 sults of this method. The normal contents ranged at that 

 time between 10-14%. In bad years with a mean of 

 10% ; in good ones it was from 12 to 14%.^ Even cases 

 of 9.5 and 17.5% were not rare.^ From 1878 to 1881 

 the method of polarization spread in Germany and Aus- 

 tria; I need only mention the names of Dippe of Qued- 

 linburg, Rimpau^ Heine and the Klein-Wanzleben fac- 

 tory. The progress was slow but sure. In most factories 

 the beets are examined only comparatively, except in 

 the case of the best ones, in which the polarization index 

 w^as actually determined. In the w^orks of Messrs. 

 KuHN & Co., however, at Naarden (Holland) this in- 

 dex has been directly determined every year for over 

 300,000 plants. Through the kindness of these gentle- 

 men I obtained in 1896 the indices of 40,000 roots; they 

 made a very beautiful curve with a mean at 15.5% (Fig. 

 22.) 



Selection is then carried out with reference to these 

 figures in such a way that sufficient plants are always 

 available for seed. The result of polarization deter- 

 mines the limits of the groups. I shall now give some 

 figures for 1892. Roots with less than 14% were not 

 planted for seed. Those with from 14-16% formed the 

 seed plants for commercial seed ; there were 20 to 30 of 



^ Langethal, LandwirthschaftUche PHanzcnkimde, III, 1874, P- 

 69. 



^ Jahreshericht dcr Zuckerindustrie, Vol. 9, p. 39 etc. 



