The origin and development of the umbilical cord, and its relation to the amnion / by James Foulis, M.D.

  • Foulis, James.
Date:
[1900]
Catalogue details

Licence: In copyright

Credit: The origin and development of the umbilical cord, and its relation to the amnion / by James Foulis, M.D. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    of the latter transversely, yet it can be seen in the sections, that these lateral somatopleure folds give off the amnion membrane in this region just as in other situations. It is in this region that the amnion is given off from the somatopleure fold at the root of the Bauchstiel, and it encases the whole rump and is pushed before it as the rump grows and becomes larger. In Fig. 2 Plate ii. the rump end of the embryo from which these last sections have been prepared is well shown ; and it will be at once seen that the ventral string or Bauch- stiel is not a continuation of the tail end of the embryo, but that it is a mesoblastic out-growth from the ventral surface of the embryo with the allantoic arteries and tube within its central part. This mesoblastic out-growth is embraced by the two lateral somatopleure folds with the large allantoic veins in their substance. These somatopleure folds gradually come to lie at the side and under surface of the Bauchstiel as the ventral string or Bauchstiel expands laterally, and as it passes outwards over the ventral surface of the rump end of the embryo. The amnion membrane everywhere is an extension of these folds in all situations. The last section, Fig. 12, which I shall describe is one of the last of the series. The section was made by the knife passing vertically downwards through the widely expanded Bauchstiel and through the very rump end of the embryo lying below it. A thick ring of somatopleure fold, O, is here seen around a shaving cut off the enclosed rump. This ring of somatopleure is part of the bag which surrounds the whole rump end of the embryo at this stage, and it is derived from the caudal somatopleure fold at the root and under surface of the Bauchstiel. As the general amnion sac later on becomes distended with fluid this bag of somatopleure fold round the rump is also distended, and the somatopleure fold is stretched out into the thin amnion membrane continuous with that whirli everywhere encloses the body of the embryo. It is interesting to note here the distance that exists between the under surface of the Bauchstiel and the meso- blastic ring surrounding the rump shaving. The Bauchstiel, or ventral string, as it lies above this ring is seen now to^ be very widely expanded and flattened out, and in the midst of it is seen (in section) the widely dilated allantoic tube