The most advanced theory, however, is that the foetus derives nourishment from the amniotic fluid, and Dr. Jerome A. Anderson sums up his highly interesting paper on the "Nutrition of the Foetus" in the American Journal of Obstetrics, Vol. XXI, July, 1888, as follows:
"To briefly sum up the facts supporting amniotic nutrition:
"1st. The constant presence of nutritive substances in the amniotic fluid during the whole period of gestation.
"2nd. The certainty of the absorption by a growing, almost skinless, foetus of any nutritive material in which it is constantly bathed.
"3rd. The permeability of the digestive tract at an early period, and the necessary entrance therein, according to the laws of hydrostatics, of the albuminous amniotic fluid.
"4th. The presence of, as it seems to me, bonâ fide débris of digestion, or meconium, in the lower intestine.
"5th. The presence of urine in the bladder, and bile in the upper intestine; their normal locations.
"6th. The mechanical difficulties opposing direct nutrition through the placenta, and the impossibility of nourishment by this method during the early stages of embryonic life previous to the formation of the placenta or umbilical vesicle.