Article contents
XI.—A Previllous Human Ovum, aged Nine to Ten Days (The Davies-Harding Ovum)
Published online by Cambridge University Press: 06 July 2012
Extract
Within recent years several human ova in the previllous stage of development have been discovered and their study, taken in conjunction with the detailed observations of Heuser and Streeter (1941) on the development of the macaque embryo, has resulted in fundamental modifications of the views previously held concerning the early development of the human embryo.
The outlook on early human embryology comprises three phases: first, the phase when only very few specimens had been discovered and the tentative conclusions drawn from their study were to a considerable extent merely surmised by analogy with the phenomena known to occur in the development of other animals; second, the phase where sufficient material has been acquired to enable investigators to verify or deny some of these postulations and even to suspect certain possibilities—like variations in the degree of development of the various elements in embryos of approximately the same age such as is known to occur in other mammals, or early histological changes indicating pathological relations between the embryonic and maternal structures which may foreshadow the failure of continued embryono-maternal relations and impending abortion; and third, a phase when the specimens will be so numerous that the conclusions of the earlier periods can be established with certainty or definitely refuted. At present, early human embryological study is in the second phase, and the early attainment of the third phase is desirable to fill gaps in the present knowledge of the stages in the development of several structures (e.g. the yolk-sac, the amnio-embryonic vesicle, etc.) and to determine details necessary for a more precise comparison of the development of the human ovum with that of other primate and of lower vertebrate forms.
- Type
- Research Article
- Information
- Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 61 , Issue 2 , 1947 , pp. 315 - 326
- Copyright
- Copyright © Royal Society of Edinburgh 1947
References
References to Literature
- 3
- Cited by