. Manual of antenatal pathology and hygiene : the foetus. foetus ; normally, however, vitelline nutrition is of short duration,being limited by the close of the neofoetal period, or very soon there-after. With some forms of monstrosity it may be greatly prolonged,and, even when no malformation exists in the infant, persistent andpervious vitelline vessels may be traced in the cord and full-timeplacenta, and these may contain blood. An example of these per- NUTRITION OF THE FOETUS 155 inanent vitelline vessels I met with some years ago; the specimen ishere figured (Fig. 27). More recently Bover
. Manual of antenatal pathology and hygiene : the foetus. foetus ; normally, however, vitelline nutrition is of short duration,being limited by the close of the neofoetal period, or very soon there-after. With some forms of monstrosity it may be greatly prolonged,and, even when no malformation exists in the infant, persistent andpervious vitelline vessels may be traced in the cord and full-timeplacenta, and these may contain blood. An example of these per- NUTRITION OF THE FOETUS 155 inanent vitelline vessels I met with some years ago; the specimen ishere figured (Fig. 27). More recently Bovero has described a similarcase, in which he was able to inject the vessels {Internal. MoncUschr. u. Physiol., xii. 31, 1895). To summarise at this stage in our consideration of the subject inhand: the liquor anniii is a certain but small source of food supplyto the foetus, even in the later months ; the part played by theumbilical vesicle and its vessels is under normal circumstancesfinished in the early weeks of utero-gestation, but may be less. Fig. 27.—Placenta with persistent Umbilical Vesicle {a), and vitellinevessels {h, b, h, h). Reduced by about one-third. temporary under certain unusual conditions. Manifestly, there mustbe some other organ of foetal nutrition which has not yet been referredto, for it is impossible to accept the feebly nutritious liquor amnii andthe temporary yolk-sac as sufficient sources of food for the rapidlygrowing unborn infant. That organ is universally admitted to be theplacenta. The reader will be not unprepared for the conclusion that thejolacenla is the chief organ of nutrition of the foetus; for the sidelights upon the subject that have been got from the study of the 156 ANTENATAL PATHOLOGY AND HYGIENE temperature of the foetus, of the chemical analyses that have beenmade of its tissues and of the placental substance, and of the histologyof the blood of the umbilical vein and arteries, have all tended tothrow into prominence the pla
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