from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
DEAD-BORN, descent, persons. Children dead-born are considered, in law, as
if they had never been conceived, so that no one can claim a title, by
descent, through such dead-born child. This is the doctrine of the civil
law. Dig. 50, 16, 129. Non nasci, et natum mori, pare, sunt. Mortuus exitus,
non est exitus. Civil Code of Louis. art. 28. A child in ventre sa mere is
considered in being, only when it is for its advantage, and not for the
benefit of a third person. The rule in the common law is, probably, the
same, that a dead-born child is to be considered as if he had never been
conceived or born in other words, it is presumed he never had life. it being
a maxim of the common law, that mortuus exitus non est exitus. Co. Litt. 29
b. See 2 Paige, R. 35; Domat, liv. prel. t. 2, s. 1, n. 4, 6; 4 Ves. 334.