10638 
observed in ‘the different crossings are fully and satisfactorily explained 
by this conception of the occurrence of factors of breadth and the 
action of the factors B and C. 
Common blue flax AABBCC and common white AABB, which 
have the same breadth and when crossed give only offspring of this 
breadth, do not form in crossing a single individual in which the 
factor C occurs alone, i.e. without B. Either C is absent from the 
offspring as in the white, or B occurs together with C, as in the 
blue. The factors for broadness are not inhibited in any single 
individual and this explains why the white, as well as the blue 
offspring have ail the same breadth. 
In crossing the common blue flax AALBBCC with the Egyptian 
AABBCC, and the common white AALS with the Egyptian 
AABBCC there is not either produced any offspring in which C appears 
without £ also. The factors for broadness were not inhibited in a 
single individual. The differences in breadth between the P-varieties 
of these two crossings will therefore not disturb the phenomena, 
which will present themselves in accordance with the law of segre- 
gation and this is indeed observed. 
In the second crossing, namely that between the common white 
and the Egyptian flax, there exists in the P-varieties a difference in 
colour as well as in breadth, and it was observed that these two 
characters behave quite independently of each other. This now 
becomes clear, for C is absent from the white offspring and the 
action of C' is inhibited by B in the blue; the factors for broadness 
are not limited, in the white as little as in the blue individuals. 
But it further becomes evident that complete independence of the 
colour and breadth is only superficial. In a certain sense there is 
indeed an interdependence between them, for the same factor C 
which is necessary for the occurrence of the blue colour. has a 
limiting action on the factors for broadness, and if the factor 6 
alone were to disappear from the blue-flowering offspring, then on 
this account colour as well as breadth would change. The colour 
would then become white, because C alone cannot produce blue, 
and the breadth would be lessened under the influence of C alone. 
In this crossing the relationship is, however, so affected by the 
presence of 5 that the interdependence between the factors for 
broadness .and colour is not noticeable and these characters behave 
independently. It is therefore clear that when in a crossing two 
characters behave quite independently we may not conclude, that 
an interrelation between the factors for these characters is wholly 
wanting. 
69 
Proceedings Royal Acad. Amsterdam. Vol. XVIII. 
