AN EARLY STAGE OF AN EXPERIMENTALLY PRODUCED EXTRAUTERINE PREGNANCY AND THE SPONTANEOUS PARTHENOGENESIS OF THE EGGS IN THE OVARY OF THE GUINEA PIG

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Abstract
1. It is possible in the case of guinea pigs to produce experimentally the first stages of an extrauterine pregnancy. 2. In a similar manner, as in the case of guinea pigs experimental interferences of various kinds are not able to call forth the production of deciduomata in the connective tissue outside of the uterine mucosa after the discharge into the circulation of the sensitizing substance which is secreted by the corpus luteum, the developing ovum is unable to call forth a decidual reaction. 3. Under the conditions produced by us experimentally the development of the embryo is very much retarded and will in all probability come to a standstill after some time. Neither does the embryonal placenta develop in an entirely normal manner, although quantitatively the embryonal placental structures preponderate considerably over the embryonal proper. It is very probable that the lack of the decidual and of the typical blood vessel reaction on the part of the host connective tissue is the cause of this abnormal development. In man an extrauterine decidua can develop and accordingly here a fully developed extrauterine pregnancy is not rare. As we have shown previously the effect of the extirpation of the corpora lutea on the formation of the decidua and on the development of pregnancy is approximately parallel. This is an additional fact which renders probable the significance of the decidual reaction for the complete development of the extrauterine pregnancy. The decidual reaction is at least one of the conditions which has to be considered in this connection. 4. Notwithstanding the presence of a young, developing embryo in the extrauterine connective tissue a degeneration of the corpora lutea and a new ovulation took place in the ovary. This proves that the persistence of the corpora lutea during pregnancy does not depend upon a substance secreted by the embryo; it is probable that the growth of the decidua perhaps in combination with the growth of the embryo prolongs directly or indirectly the life of the corpora lutea during pregnancy. Thus far experiments, which we have carried out in order to decide this question, have shown that the presence of living and growing deciduomata prolongs the sexual period; furthermore that pregnancy prolongs the life of the deciduomata. Further investigation will decide whether or not these effects are exerted indirectly by means of the corpus luteum. 5. Our experiments render it certain that the structures which we found in a considerable number of guinea pigs and which we formerly interpreted as early stages of parthenogenetically developed pregnancies in the ovaries of guinea pigs really represent a relatively far going parthenogenetic development of ova which may lead to the formation of embryos in the germ layer stage which however usually leads merely to the formation of an embryonal placenta probably as a response of the developing ovum to the influence exerted by the contact with the surrounding host tissue. We show furthermore the significance these findings have for the interpretation of the teratomata and chorionepitheliomata of the germinal glands. 6. The embryonal wander cells destroy outside as well as within the wall of the uterus bloodvessels of the surrounding host tissue in the ovary as well as in the peritoneal connective tissue and they thus cause hemorrhages in the surrounding host tissue.

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