HOUWINK’S EXPER. CONC. THE ORIGIN OF SOME DOMESTIC ANIMALS 267 
211.7 and 211.8. All further crosses attempted gave either no eggs at 
all or unfertilised ones. Still the results of this year are more encoura- 
ging than those of the former. When the peculiar pairing-habits of 
varius are better understood, the results may gradually become more 
satisfactory’. Unfortunately they did not; not asingle chick was born in 
1920 while 1921 gave 6 chicks only, all of which died in thesame year. Nor 
were any chicks born in 1922 but in that year the birds were removed 
to Mook where it was very cold and no special attention was paid to 
the breeding, the eggs being left in the nests, until the female cared to 
begin brooding which she probably did not in most cases. In 1923 some 
chicks were obtained from Gallus Temminckii showing that this cock 
remained fertile although 8 years old now, but the number was small 
and of them some died as chicks, we shall report about these results at 
some future date. In 1924 this cock was still fertile. 
Until this season, we were inclined to ascribe much of the poor results 
to the fact that all these experiments were made during the war, in 
which our country took no part, but was treated by the belligerents as 
if it did, our oversea-supplies being cut off, so that even the food for 
man became scarce and the obtention of food for, even so small a num- 
ber of animals, as those concerned in the experiments, became almost 
impossible. But all this applied also to the Sonnerat-crosses which, 
~ according to the note made in 1919 were much more fertile. In 1923, 
when food was abundant again, the senior-author however had very 
poor results from the Sonnerat-crosses also, partly, but by no means 
wholly, due to the fact that some of the animals had reached rather 
advanced age. In that year the birds were kept under very good condi- 
tions and were in first rate health, still the results were poor. Experi- 
ments of this kind require a good deal of experience, especially as to the 
best food for the animals, so that it would, in the opinion of the senior 
author, be rash to conclude that varius-hybrids are less fertile than 
those with Sonnerat, as a matter of fact, the little we know of the 
varius-crosses in Java speaks against this view. 
About this the HAGEDOORNS say in their ,,Relative Value of the 
Processes causing Evolution’ p. 234 seq. 
„These Bekisars (F, hybrids of domestic poultry x varius) are by no 
means sterile. In Pasoeroean where a great number of Bekisars are kept 
by Chinese we saw several very beautiful cocks in cages, bred from 
_Bekisar fathers. We remember a white male with a long bluish tail and 
