Abstract
The extent to which fetal gastro-intestinal movements occur normally in intrauterine life is unknown. However, we are led to believe that they are present because meconium passed at birth contains vernix caseosum derived from the amniotic fluid which the human fetus swallows in large amounts by the sixth month. 1 , 2 Carlson and Ginsburg 3 recorded vigorous and frequent hunger contractions in puppies delivered 8-10 days prematurely and direct observations of “spontaneous” fetal intestinal movements have been made by Yanase, 4 and others. 5 - 9 Asphyxial conditions prevailed in the latter instances except when viable fetuses near term were used.
We have observed directly and recorded in motion pictures intestinal activities in fetal cats and in kittens one and 2 days after birth. Fetuses were delivered by Caesarian section performed on animals previously decerebrated under ether by tying internal carotid and basilar arteries. This made it possible to dispense with anesthesia. Fetuses were first examined with the placental circulation intact in a constant temperature bath of Locke's solution. Later the umbilical cord was clamped or the placenta disengaged from the uterus. Local procain anesthesia was used for the young kittens. We tried to evaluate the part played by anoxemia in influencing fetal gut motility and had available blood-oxygen determinations made in the same specimens and in litter mates as well as in the mother cats by the Van Slyke and Neill method.
Local constrictions of the intestinal wall were induced by mechanical and faradic stimulation in cat embryos 18.5 mm long weighing about a gram. “Spontaneous” movements were seen in specimens of 35 mm (3 g) at about the middle of gestation. Strength of intestinal movements increased rapidly from then on and by 70 mm (18 g) the behavior of the stomach and intestines appeared to be no different from that in unanesthetized kittens a day or two old (110-120 g).
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