144 LOTSY AND KUIPER, A PRELIM. STATEMENT OF THE RESULTS OF MR. 
the maternal upon extension and distribution of the pigmentation 
and upon the legfeathering. New characters appeared: solid black 
colour, speckling of the feathers. In the second generation certain 
characters show the mendelian segregation but the proportional 
numbers were reverse in the reciprocal cross or at least there was 
an inclination to this reversion. This was the case with form of 
the comb, colour of the plumage, legcolour. Other characters e.g. 
complete pigmentation, legfeathering, show mendelian segregation 
in One experiment but in the reciprocal they disappear, sometimes 
not only in Fy, but also in Fo, and they recur sometimes in 
later generations. To explain these curious facts, VON TSCHERMAK 
assumes a characteristic weakening (Valenzminderung) of factors 
(Theory of Genastheny). 
Upon his experiments, quite insufficient as they were, the author 
bases a theory of great scope in which there are points, no doubt, 
that draw the attention but which, as demonstrated above, was 
founded very insufficiently. 
Notwithstanding this, the phenomena described by v. TSCHERMAK 
are important enough to justify new conformable experiments with 
other breeds. | 
So Mr. HOUWINK, after taking the advice of his ent assistent 
of those days, the junior author of this paper, decided upon repe- 
tition of the experiments, with two breeds of widely diverging 
characters, which gave the best chances to show reciprocal diffe- 
rences, if these might arise. 
In order to meet as far as possible the objections that could 
arise against the purity of the races, used by v. TsCHERMAK, he 
choose the Red Jungle Fowl, Gallus gallus (G. bankiva), which 
he had bred pure for several years before, and the Silky fowl 
Gallus domesticus sericeus alba. 
2. FORMER INVESTIGATIONS. 
The cross Bankiva X Silky was made before several times by 
previous experimenters. 
The Silky-feathering is a recessive character. This was already 
known to TEGETMEIER (1866) and Darwin (1876). 
BATESON (1909) treats of the heredity of the comb, the silky 
feathering and the pigmentation of the skin. DAVENPORT (1906) bred 
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