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The ancients imagined that the woman had her testicles, as well as the man, and her own semen. They taught, that in the coitus there was a mixture of the male and female semen in the uterus, and that from a process like fermentation between those two fluids, an embryo was produced. Lewenhoeck said the embryo belonged to the male; and saw, or thought he saw, animalcules in the male semen, resembling the animals to which they belonged. Spallanzani says, that the semen of male animals having no animalcules, impregnates as certainly as that of those which have them. This shows that those animalcules are not embryos. Steno, observing that there were round vesicles in the testicles of women, like the eggs of birds, called them ovaria, and said their structure was exactly similar to the ovaria of birds. After this the immortal Harvey broached the doctrine of “omnia ab ovo ;" that all animals were produced from ova. “ Nos autem asserimus, “ animalia omnia, et hominem ipsum, ex quibusdam ovis nasci." The ova in the ovaria of rabbits are particularly described by De Graaf, whence Haller calls them ova Graffiana. But the ovaria of quadrupeds often contain vesicles of the hydatid kind; and it becomes difficult to distinguish between what are vesicles, and what are ova. The mark with me is this: the ova are inclosed in a capsule highly vascular from arteries and veins, carrying red blood. The hydatid vesicles are not vascular; at least their vessels carry no red blood. The calyx and the ovum, after impregnation, and even before it, in the state in which the quadruped is said to behot , become black as ink, from the greater derivation of blood; and the ova resemble dark spots: they also come nearer the surface of the ovarium, so as to pout or project, at last, like the nipple in a woman's breast. Some hours after impregnation, the calyx and the coverings of the ovaria burst, and the ovum escapes; may fall into the general cavity of the abdomen, and form an extra-uterine fœtus; but almost always falls into the mouth of the fallopian tube, whose fimbriæ, like fingers, grasp the ovarium, exactly at the place where the ovum is to escape. What the appearance of the ovum was, when deprived of its calyx, or when descending the fallopian tube, was not known. De Graaf discovered this in the fallopian tubes of rabbits, in the year 1672; and says, “ minutissima “ ova invenimus, quæ licet perexigua, gemina, tamen, tunica “ amiciuntur; " and then adds, “ hæc quamvis incredibilia, “ nobis demonstratu facillima sunt."

philosophical transactions of the royal society of london

IX. Experiments in which, on the third day after impregnation, the ova of rabbits were found in the fallopian tubes; and on the fourth day after impregnation in the uterus itself; with the first appearances of the fœtys