The experiments of Albini in Naples (according to Kronecker’s report ‘_Centralblatt für medicinische Wissenschaft_,’ 1868), which he made during four years in his great poultry-yard showed in the first place that hens for eight days after being separated from the cock laid none but fertile eggs. On the ninth and tenth day the fertile and infertile eggs were of equal number. On the twelfth day all the eggs were infertile. Nevertheless fertile eggs appeared even on the eighteenth day. It is possible that they had been impregnated by spermatozoa which had remained in the folds of the mucous membrane of the uterus. Hens never yet impregnated, or such as had not been impregnated for at least a month, in three days (after impregnation) laid fertile eggs, which increased in number daily. According to Albini, hens can in Naples leave the eggs which they are hatching. The shell can be partly broken off and again replaced without the embryos necessarily perishing. But care must be taken that no fungoid growth reaches the germ, as this is easily fatal to it. Indeed, it has been recently shown that new-laid or well-preserved eggs are free from all micro-organisms. When these appear they have made their way into the egg through the mechanically injured or otherwise altered calcareous shell. They do not have their origin in the egg from the mother. The egg of the bird is perfectly free from micro-organisms when it is laid. If, however, only traces of pure cultivations of micro-organisms be in a suitable way applied to such eggs externally (Lenderer), they always have a fatal effect upon the developing germ, even when they are not any of the so-called pathogenic microbes. * * * * * And now the result of Albini’s breeding experiments upon poultry with respect to the origin of sex. From three to six days after intercourse with the cock the hens lay eggs, from which on the average an equal number of males and females are developed. In the warmer part of the year the number of males appears to be greater. _Better nourishment of parents seems also to exercise an influence over the sex of the young._ Such eggs as were laid from ten to fifteen days after complete separation from the cock, gave when hatched generally a distinctly greater number of females. Albini found that the greater number of these died of anæmia. He ascribed that to imperfect fertilization, and considered that development of an excessive number of females was to be ascribed to the same cause.