| Abstract: | The observation of embryonic mammary glands in male and female mice under the electron microscope has shown on one hand that the cellular ultrastructure of the buds is characterized by embryonic tissue only slightly differentiated, and on the other that, under the influence of testicular hormone, the detachment of the anlage from the epidermis in fourteen-day old embryos results in an important modification in the relationship between the ectoderm and the mesenchyme at the level of the neck of the gland rudiment. The basal membrane is destroyed and numerous centers of necrosis can be seen starting from the dense bodies in the ectodermic cells of the ruptured zone. |
