In the woman, more particularly, the chorion is externally rough and viscous, but internally it is smooth, slippery, and in- terwoven with abundance of vessels. In the woman, also, the upper part is thick and soft, but the lower is thinner and more membranous in character.
The placenta in the woman grows to the upper part of this membrane. In the sheep, numerous carunculse adhere to it at various points. In the fallow and red- deer the ovum is united to the uterus in five places only ; whilst in the mare it is in contact with the inner surface of the uterus by an almost infinite number of points of attachment. Hence Fabricius[1] states that in almost all viviparous animals there is a soft, loose, porous, and thick fleshy body of a dark colour, in intimate union with the terminations of the umbilical vessels ; he com- pares it to a sponge, or to the loose parenchyma of the liver or spleen ; hence, too, it was called by Galen [2] " glandular flesh " and it is now commonly known by the name of the uterine liver, in which the extremities of the umbilical vessels ramify to bring nutriment from the uterus to the foetus.
But this fleshy substance is not found in all animals, nor at all periods of utero-gestation ; but in those alone in which the conception adheres to the uterus ; and then only when it becomes attached for the purpose of taking up nutriment. At the commencement the " conception" (like an egg placed within the uterus) is found in contact with every part of the uterus, yet at no point is it adherent ; but produces and nourishes the embryo out of the humours contained within it, as I have explained in the instance of the hen's egg. This adhe- sion, or growing together, first takes place, and the fleshy mass (constituting the bond of union between the " conception" and the uterus) is first produced, when the foetus becomes perfectly formed, and, through want either of different or more abundant nourishment, dispatches the extremities of the umbilical vessels to the uterus, that from hence, (as plants do from the earth by their radicles) it may absorb the nutrient juices. For in the beginning, as I have said, when the "punctum saliens" and the blood can alone be seen, the ramifications of the umbilical vessels are only visible in the colliquament and amnion. When,
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