Review: Xenia in Fowls 



217 



influence of some kind on the maternal 

 organism; and Walther expresses him- 

 self as willing to entertain such an idea 

 as a working hypothesis, at least. 



CONTRADICTCRY EVIDENCE 



But perhaps this discussion of how 

 xenia takes place in fowls is really 



in part contradicted, and directly con- 

 tradicted, by experiments of Professor 

 A. R. Walther of Giessen,^ which appear 

 to have been made with a great deal of 

 care, and to have been analyzed by 

 sound mathematical methods. 



Walther's conclusions are based on 

 examination of 630 eggs laid by thirteen 

 hens. His meth- 

 od of operation 

 was to cross races 

 differing not only 

 in egg-shell col- 

 or, but in size — 

 that is, bantams 

 and ordinary 

 fowls. Every egg 

 laid was incu- 

 bated, and if it 

 was found to be 

 infertile, it was 

 thrown out, a 

 possible source of 

 error thus being 

 avoided. As was 

 pointed out 

 above, Holde- 

 fieiss' results are 

 of little conse- 

 quence as a proof 

 of xenia, partly 

 because there is 

 reason to believe 

 that many of the 

 eggs he examined 

 had not been fer- 

 ilized at all, and 

 from such eggs it 

 it is obvious that 

 no evidence 

 about xenia — the 

 influence of fer- 

 tilization — could 

 be expected. They might, however, be 

 covered by von Tschermak's second 

 hypothesis's described above. 



The points taken into consideration 

 by Walther were (1) the weight, (2) the 

 shape, (3) the glossiness, and (4) the 

 color of the eggs. It will not be worth 

 while to quote Walther's statistics, but 

 his own conclusions may be indicated. 

 1. It could not be found that the 

 cock produced any effect whatever on 



= Walther, Adolph R. Ueber den Einfluss der Rassenkreuzung auf Gewicht, Form, Glanz und 

 Farbe der Huhnereier. Landwirthschaftliche Jahrbiicher, XLVI, Heft 1, S. 89-104, Berlin, 1914. 



►ERIMENTS WITH HENS' EGGS 



ig range in size of eggs from a single flock of hens, all of the same breed. Experiments 

 e smaller, as she approaches the end of her laying period; and the last one, it is generally 

 : the small size of "pullets' eggs" is also a matter of common knowledge. On the whole, 

 ige weight, and the experiments of the Rhode Island Station indicate that this weight is a 

 I a flock of one breed, graphically shown in the photograph, renders it necessary that any 

 I records — otherwise he is likely to draw some wholly erroneous conclusions. (Fig. 11.) 



beside the mark — because it may not 

 really take place at all! Until von 

 Tschermak's experiments with canaries 

 have been substantially repeated by 

 other investigators, and have with- 

 stood a critical examination by some 

 one able to speak with authority, this 

 small amount of evidence can not be 

 given great weight. It would not be 

 entitled to very much consideration 

 even if it were uncontradicted; but it is 



