
18 (210) SURPASSING UPWARD AND DOWNWARD OF THE INDICES 
ian property with dominance of polydactylism, whilst irregularities 
may sometimes occur. The polydactylic breeding of CASTLE shows 
these irregularities on a large scale. There is no dominance, but a, very 
evidently, varying prepotence. There are peculiar prepotences, says 
CASTLE (p. 22), which perhaps can pass from generation to generation. 
The value of gametic prepotence is larger than that of ancestors. Poly- 
dactylism (suddenly) appears, is inherited during two to five gener- 
ations and then disappears again, undoubtedly so much weakened by 
repeated crossings that, if still it happens, its appearing is no longer 
to be observed. 
In his last publication (1920) CASTLE chooses his standpoint as fol- 
lows: „Now as to the interpretation, I have assumed that the segreg- 
ation is of à monoh y brid sort involving in each cross one principal pair 
of allelomorphic factors and that the ’’’’mutual modification’’’” of 
types seen in F, is due to ”’”residual heredity.””” PUNNETT objects to 
the assumption of modification and to the term residual heredity, 
unless it is understood in both cases that factorial recombination is. 
meant rather than factorial modification. I am quite ready to concede 
the point. I used the expression residual heredity to cover the unan- 
alysed genetica gencies responsible for the observed modification in 
3299) 
the extracted types.” 
All investigators now are inclined to interprete the phenomenon of 
selection by the polymery-theory (see also p 45). R. GOLDSCHMIDT 
who in the 2rd edition of his book (1913, p. 264) a different potence of 
a factor accepts, now (1920, S. 363) sees in the quantitative variability 
of genes, that he accepts for the interpretation of intersexuality a new 
possibility to explain selection. | 
As CASTLE makes a distinction between a prepotence of the gametes 
and a prepotence through the influence of preceding generations 
(ancestral influence), in the cases of our tables II and III as far as they 
are known we shall examine the ancestors and their eventual influence 
upon the off-spring of the parents. For the Mendelist the ancestral 
influence is confined, as we have to take in view, to the obvious way 
which is followed by hereditary factors in successive generations and- 
which therefore in the formula of parents has been fully taken into 
consideration. Ancestral influence in CASTLE’S interpretation closely 
approaches to a peculiar hereditary potence which is taken in account 
in the practice of breeding. CASTLE thinks it possible (in his former 
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