TJEBBES, KOOIMAN, ERFELIJKHEIDSONDERZOEKINGEN BIJ BOONEN Ill 537 
"We succeeded in this way to raise 2 albino’s to maturity in 1918. 
These soon produced little patches of green on their composite 
leaves and later on even stripes of chlorophyli on their pods as 
may be seen on the colored plate and on photo A. Each of the 
two grafts produced one ripe pod containing 2 and 3 seeds respec- 
tively, which had exactly the same color as the normal seeds. 
The ivory-white seedlings obtained from every one of these seeds 
were again grafted on normal ones; four of these succeeded and 
are shown on photo C; two of these died by an attack of Pytium 
de Baryanum the two surviving ones behaved exactly as the grafts 
of 1918; one of them, figured on photo A, has a nearly ripe pod 
striped with green. 
As to the origin of this albino-throwing strain of beans we venture 
to suggest that it may have arisen from the cross of a flower of a 
normal branch with a flower on a white branch of a sectorially 
chimaeric plant. 
The first plant throwing whites has then been a heterozygote, as 
we are forced to presume to have been the case on account of 
the non-viability of the whites. 
If. fi. JOHANNSEN (Zeitschrift für induktive Abstammungs- und 
Vererbungslehre I, side 2) had made such a cross, he would pro- 
bably have obtained a strain like ours. 
As however crossings in Dwarf beans in nature are rare we are 
inclined to believe, that the loss of the factor, that enables the plant 
to make chlorophyll (and that we suppose to be of a chemical nature) 
has taken place in one normal flower. Amongst the gametes formed 
in that flower some, or perhaps one, did not possess this indispen- 
sable chlorophyll-constituent, thus causing the origin of a hetero- 
zygotic seed that became the ancestor of our albino throwing strain. 
Another question is, how to explain the appearance of the green 
patches on the higher (composite) leaves and on the pods? Are 
our albinos no real ones, but only an extreme case of variegation ? 
Or have we here to deal with some chemical influence from the 
normal plant on the graft? Our experiments do not allow us to 
decide this question. 
We intend to do some more work on this strain in order to 
throw more light on this and other similar cases of albinism and 
‘variegation, We also will try to make artificial cross fertilizations 
