In most laboratory animals (e.g. guinea pig, rat, rabbit) the appearance of the cervix is very variable, and is characterized by a glandular differentiation between the vagina and the body of the uterus. The author has tried to provoke variations in the glandular morphology of the cervix by injection of total folliculin, of ovarian lipids, corpus luteum extracts, purified folliculin, and synthetic proluton. In the guinea pig injection of folliculin first thickened the basal layers of the vagina, and then caused desquamation; in the body of the uterus it provoked the growth of glands and the apparition of decidual cells; secretion from the mucosa increased. Placental lipids caused the same effects, while luteinizing products did not. Pure folliculin caused on the cervical glands the same effects as estrogen products, but more quickly. Testicular lipids caused the development of cervical glands and an abundant secretion of mucus; keratinization was induced more rapidly in the castrated female. The same effects, with slight differences, were obtained after injections in the rat and in the rabbit. Further studies are required before the results can be transferred to the clinical field.