The Accuracy of the Macroscopic Method in Identifying Fertile Unincubated Germ Discs

Abstract

A recent paper from this laboratory (Kosin, 1944) has described a method for differentiating fertile and infertile dissected, unincubated hen’s eggs. After the paper was submitted for publication, the author came upon the work of Barfurth (1895) which describes the macroscopic difference between the two types of eggs. This morphological difference also had been observed by still earlier embryologists (His, Oellacher and others). The practical significance of this older knowledge, however, was evidently overlooked by contemporary investigators. The 1944 hatching season afforded an opportunity to test the accuracy of the method on a rather extensive scale. It is a routine practice at this Division to test the fertilizing ability of breeding males by making a preliminary setting of eggs laid by breeding hens mated to the respective sires For the purpose of the present test, this routine was slightly modified. Eggs which were to be used in the test were . . .