HOUWINK’S EXPER. CONC. THE ORIGIN OF SOME DOMESTIC ANIMALS. 141: 
20, Onderzoekingen over kleur en teekening bij runderen. 
Colour inheritance in cattle, by K. Kuiper. 
Genetica 1920 pg. 137—i61. (regarding exp. 17). 
Appeared in a shortened form in Journal of Heredity 1921) 
(no. 3) pg. 102—109. 
30, Steriele soortsbastaarden (Sterile hybrids of species) by K.KUIPER. 
Genetica 1920 pg. 289—299. (regarding nos 6, 7, 24, 25). 
Now that Mr. Houwınk was obliged alas to dissolve his expe- 
rimentstation in Meppel (1921) it would be regrettable to allow- 
all his energy and all his unfinished work to fall into oblivion. 
The experiments with wild fowlspecies will be continued by the 
Dutch Society for the advance of Scientific Culture, those about 
hare-rabbit crosses in the College of Agriculture at Wageningen. 
About the other series we hope to give an account within a short: 
time. The first one is following here. 
if 
SOME REMARKABLE DIFFERENCES BETWEEN THE RECIPROCAL HYBRIDS 
OF THE RED JUNGLE FOWL AND THE SILKY FOWL. 
1. INDUCEMENT TO THE EXPERIMENTS. 
In 1917 Prof. A. v. TSCHERMAK published an article (Biologisches 
Zentralblatt vol. 37, pgs. 217—277) Ueber das verschiedene Er- 
gebnis reziproker Kreuzung von Hühnerrassen und über dessen 
Bedeutung für die Vererbungslehre (Theorie der Anlagenschwächung 
oder Genasthenie). 
The following breeds were chiefly used, 
Ia. Buff Cochin 2 x Minorca (old) white, with rosecomb. ¢. 
Ib. The reciprocal cross of the former — 
Ila. Partridge Leghorn 2 X Plymouth Rock 4. 
II. The reciprocal cross of the latter. 
With only two animals, male and female, of each breed, bought 
from the well-known poultry-farm Kleinmiinchen (Ober-Oesterreich), 
as garanteed thorough-bred, the experiments were started in 1912. 
v. TSCHERMAK is absolutely convinced of the purity of his 
P-material. He writes: „Die von mir verwendeten Rassetiere haben 
bei Inzucht ein tadellos konstanter Nachkommenschaft geliefert, 
sich also als ,,ziichterisch oder phaenotypisch rein” erwiesen. Auch. 
