Dr. C. C . Guthrie ('08) has reported the results of transplanting ovaries from black to white hens and vice versa. A blackplumaged hen furnished by transplantation with ' white' eggs and mated to a white cock gave "about equal numbers of white and spotted" chicks. Guthrie thinks that these black spots indicate that the black-plumaged foster-mother infected the engrafted 'white' eggs.
But a person familiar with the results of hybridizing will appreciate that Guthrie's result is better explained on the assumption that the engrafted ovary was absorbed and that the white sperm fertilized the regenerated 'black' eggs of the black hen. For the white by black cross gives white offspring. with black spots in the female chicks only, ie., half of all, as Guthrie found.
In a second set of experiments, Guthrie found that when a white hen carrying a 'black' ovary was mated to a White Leghorn male, the offspring were either white or black or spotted. Guthrie says: "The black, therefore, must have come through the black ovary." But the student of hybridization on poultry will recognize at once that, if the white-plumaged cock produced only 'white' germ cells, none of his offspring would be black even if the eggs were 'black.' Hence, the cock must have had 'black' germ cells and, very likely, the hen also, since 'White Leghorn' hens that carry 'black' germ cells are very common and frequently show, in adult life, a pure white plumage.
If two 'White Leghorns' with 'black' germcellsbemated expectation is that in four chicks one shall be black; one spotted, and So far Guthrie.
A preliminary paper covering these results was read before the Society ior Experimental Biology and Medicine, June 1910.