556 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the subsequent breeding - season. The higher the number of winter 

 eggs, the lower, in general, will be the number of fertile eggs hatched, 

 and conversely. 



There is apparently no marked superiority of hens over pullets in 

 respect of breeding performance, either in regard to fertility or hatching 

 quality of eggs. There is no indication that the fertility of eggs in the 

 pullet year and in the second breeding year are in any way correlated, 

 but there is a significant positive correlation between the percentage of 

 fertile eggs hatched in the pullet year and in the second breeding year. 

 There is no evidence that the character " fertility of eggs " (measured 

 by percentage of infertile eggs) is in any degree or manner inherited. 

 The character " hatching quality of eggs " (measured by percentage of 

 eggs hatched) is definitely inherited in the female line, and probably 

 also in the male line. 



In the last part of their paper the authors discuss the theoretical 

 import of some of the data established, such as the negative correlation 

 between fecundity and hatching quality — that is, germinal viability or 

 vigour. They compare this correlation with the association of high 

 fecundity and a high rate of infant mortality (and probably also of 

 prenatal mortality) in man, and suggest that in both cases bad con- 

 ditions of housing and nutrition, along with the organic fatigue incident 

 to the high fecundity itself, reduce the general constitutional vigour, 

 and with it the viability of the developing germ and the growing 

 organism. 



In conclusion, some points of importance for breeders are em- 

 phasized, and the lines on which further investigation — especially in 

 regard to preferential mating — is required, are indicated. 



Reproduction in the Domestic Fowl.* — R. Pearl and M. R. Curtis 

 describe in detail a case of incomplete hermaphroditism in the domestic 

 fowl. The specimen was, in its external somatic characters, an antero- 

 posterior gynandromorph. Internally, it possessed on the left side a 

 large lobulated gland in the position and anatomical relations normal to 

 the ovary. There was also a fully developed, normal oviduct in 

 functional condition on the left side. On the right side of the body 

 w T as a small organ in the position and anatomical relations normal to 

 the right testis. Attached to this organ was a normal epididymis and 

 vas deferens leading to the cloaca. Microscopical examination showed 

 that both of the reproductive organs were in a condition of extreme 

 degeneration. Neither spermatogenesis nor oogenesis could be found 

 in any part of either organ. 



Origin of Blood in Toad.f — Harald Mietens finds that the liver has 

 in early stages a pronounced blood-forming function. Blood-cells and 

 endothelial cells are formed from the elements of the hepatic primordium, 

 but the developed organ has no such function. The blood-formation in 

 the liver agrees histogenetically with what occurs in the medio-ventral 

 mesodermic blood-islands. Thus the blood has an endodermic as well as 

 a mesodermic origin. 



* Biol. Bull., xvii. (1909) pp. 271-86. 



t Jen. Zeitschr. Naturw., xlv. (1909) pp. 299-32-1 (10 figs.). 



