Wounds of the pregnant uterus

In continuation of former experiments to determine the influence of functional conditions upon processes of cell growth and cell necrosis in the ovaries, investigations of a similar character were undertaken on the pregnant uterus of the guinea pig. As is well known, the pregnant uterus responds to the stimulation of the fertilized ovum by the production of decidual tissue. It was thought possible that in the beginning of pregnancy the uterus might respond also to other stimuli such as wounds, in a way different from the ordinary uterus. Experiments were carried out in twenty six guinea pigs at different stages of pregnancy. Wounds were made in various directions in the uterus, or part of the wall of the uterus was inverted so that the mucous membrane was turned outside. It was found that at a certain stage of pregnancy, namely from the fourth to the sixth day, nodules of decidual tissue were formed at places where the continuity of the uterus had been interrupted or where the mucous membrane had been inverted. Serial sections of these nodules show that they consist of typical decidual tissue which does not include a developing ovum. The number of these nodules was either larger than the number of corpora lutea present in the ovaries which had been cut into serial sections or in other cases corpora lutea were present on only one side of the animal while the decidual nodules were present in both horns of the uterus. Under those conditions it is not likely that the formation of the decidual nodules was caused by the direct stimulation of an ovum, but it is more likely that, at the period of pregnancy, when the development of decidual tissue begins to take place normally, other stimuli are also able to call forth the production of decidual nodules.