There are several important points about the ovaries which have emerged clearly under experimental attack. Once clearly defined, in many cases accentuated through experimental conditions, some of the phenomena stand out as normal in certain species but occur in others only occasionally. An instance is the formation of corpora lutea (accessory ones) in large follicles that have not ovulated. The ova are trapped inside, but the cells of the follicle take on luteal characteristics. Known for many years, this condition was first induced experimentally by unbalanced stimulation of the ovaries with anterior pituitary extracts.1 It appears normally in the pregnant mare2 and the pregnant porcupine3 and occasionally in the nonpregnant monkey.4 More careful observations may establish this as an occasional occurrence in women!
Another instance is the extreme development of the theca folliculi, the zone immediately surrounding the basement membrane about the outer layer of follicle