THE Vessels terminating in the Navel-String, are inserted at one End, almost in the Center of the Placenta; as the other End adheres to the Navel of the Infant.
THE SECUNDINE is rough and unequal on the Outside, and smooth and soft on the Inside; and cannot be extracted, without breaking the mentioned Vessels: From hence an Effusion of Humours and Fluxion of Blood always follows it; which (according to the Woman’s State of Health) is of a fairer, or darker, red Colour.
THE Use of the SECUNDINE, is to receive and absorb the Nutritious Juice from the Womb; (as the Intestines imbibe the Chyle) which it afterwards transmits to the Infant, by the Umbilical Vein.
IN Case of Twins, or more Children, if conceived at one Time, they have but one common SECUNDINE, (notwithstanding the contrary Opinion of others) which adheres to the Fund of the Womb, by the Placenta, as above: Wherefore I must needs reject the Testimony of such Midwives, who give out that they have found the SECUNDINE, fix’d to any other Part of the Womb; tho’ I experimentally know, that it is sometimes found in the Hinder Part near the Loins, sometimes in the Forepart, sometimes near the Diaphragma, sometimes in the Right, and sometimes in the Left Side.
BUT however, we should be grossly mistaken, if from hence, we did conclude, that the SECUNDINE adher’d to any other Part, than the Bottom of the Womb: Since such erroneous Apprehensions are merely occasion’d by the various Motion, or oblique Position of the Womb; as hereafter will appear more at large.
CHAP. XIII.
Of the UMBILICAL VESSELS, or NAVEL-STRING.
THE three Umbilical Vessels consist of one Vein and Two Arteries; which compose the NAVEL-STRING, and are wrap’d up in one strong Membrane, proceeding from the Chorion and Amnion, between the Navel and Placenta.
THE Vein arises in the Placenta, from innumerable minute Vessels; proceeding thence with Spiral Contortions between the Arteries, thro’ the NAVEL-STRING, and Navel, to the Liver of the Infant; terminating in the Sinus of the Vena Porta, into which it pours the Blood and nutritious Juice received in the Placenta; which immediately proceeds to the Vena Cava, and Heart, thro’ a Cylindrical Canal (call’d Venosus) opposite to the Umbilical Vein.
THE Arteries, which are scarce half so large as the Vein, arise from the Iliacs of the Infant, or from the Aorta. They pass both Sides of the Bladder to the Navel, and thence through the NAVEL-STRING, by the like Spiral Windings, to the Placenta: where, after distributing some Branches to the Amnion and Chorion; they are divided into a very great Number of Sprigs, transferring the Blood from the Fœtus to the SECUNDINE.