I. Leitch 185 



ferencc in Genetics, (1906), p. 98, and as is demonstrated in the Elemente, 

 2nd Ed. p. 558. 



" The pure line E, with which the present paper is alone concerned, 

 is distinguished from all others in my material by having pure white 

 petals and a yellow-white colour in the rest of the flower, without a trace 

 of violet. The other lines of Princess beans have a violet tinge, often 

 weak but unmistakable. And in the crosses made between E and other 

 lines, the F^ generation has always had this violet colour in the flower, 

 and the F.2 generation has split strongly and clearly giving plants with 

 violet and plants with white flowers in the ratio 3:1. 



" Therefore line E is exceedingly well suited for further studies where 

 it is important to be sure that no inadvertant cross has occurred ; such 

 a cross would at once appear in the colour of the flowers. Line E then, 

 as I have described in my paper ' Om nogle Mutationer i rene Liniers ' 

 (Biol. Arbejder tilegnede Eug. Wanuing, K^benhavn, 1911), has twice 

 shown a sudden change in genotypical constitution, ' mu(e)tation ' — 

 and that without any alteration in its white colour — and one of the new 

 biotypes, which from its appearance (probably by vegetative mutation) 

 was homozygous and as such had proved constant for a number of years, 

 was chosen to test further the nature of the mutation. A cross was made 

 between the original, unaltered, E type and the mutant in question, 

 mutant x original. The immediate result of the cross was three seeds 

 which were sown and gave in all 62 descendant seeds, which have thus 

 Fo embryos in F^ seed-coats." 



Of these 62 seeds, two were rejected as misformed and the remaining 

 60 sown in six rows of 10 each, with two control rows of E and M 

 respectively. It was the harvest from these 60 beans that was handed 

 over to me in the Autumn of 1914 for analysis. 



The following figures from Professor Johannsen's paper show the 



amount of the difference between the original pure line E and the long 



mutant, which, for convenience, we call M. 



Original type ... L 12-459 i? 9-017 7 72-4 



Long mutant ... 1,13-564 £9-137 7 07-4 



(/ is the length-breadth index, 100 B -r- L). 



Or comparing the indices through a number of years. 



Year Original tyi>e Long mutant Difference 



