THE UMBILICAL CORD. 569
the means by which the nutrient matter is taken up, as by rootlets, and distributed to the foetus. The veins of the cord are marked at various places by knots or varices, resem- bling vesicles filled with blood ; this is a contrivance of nature to prevent the blood rushing too violently to the foetus. From the number of these knots superstitious midwives are accus- tomed to predict the number of the future offspring; and if none can be seen at all they pronounce that the woman will be ever after barren : they also absurdly prophesy by the distance between the knots about the interval to take place between the birth of each child, and also of its sex from their colour.
A like arrangement of the umbilical vessels is found in almost all foetuses furnished with a single placenta, as in the dog, mouse, and others ; but in these the cord is shorter and less convoluted. In the ox, sheep, red-deer, fallow-deer, hog, and others, in which the nutrient material is not supplied from one fleshy mass or placenta, but from several, the umbilical vessels are distributed in a different manner. The branches and extremities of these vessels are not only disseminated through the fleshy substance, but still more and chiefly through the membrane of the chorion itself by means of the most delicate fibres; exactly in the same way as the vessels are distributed in the human foetus, without the aid of the cord, before the "conception" adheres to the uterus. .Hence it is plain that the embryo does not derive all its nourishment from the pla- centa, but receives a considerable portion of it from the fluid contained in the chorion.
As to the uses of the umbilical vessels, I cannot agree with Fabricius, for he imagines that all the blood is supplied to the foetus from the uterus by means of the veins, and that the vital spirits are transmitted from the mother by the arteries. He also asserts that no part of the foetus performs any common function, but that each individual portion looks only to itself, how it may be nourished, grow, and be preserved. In like manner, because he has found no nerve in the umbilical cord, he refuses to allow sensation or voluntary motion to the foetus. Just as if the uterus or placenta of the mother were the heart or first source whence these functions are derived to the foetus, and whence heat flows in and is distributed through all its parts. All these are manifest errors. For the human foetus, even
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