othes, and warmth, for the new-born child.

XXIX.--DURATION OF PREGNANCY

The natural period of gestation is considered as forty weeks, ten lunar
months, or 280 days. A medical witness would have to admit the
possibility of gestation being prolonged to 300 days, and if this time
were not very materially exceeded it would be well to give the woman
the benefit of the doubt. It may be mentioned that 300 days is the
extreme limit fixed by the French and Scottish law. No fixed period is
assigned in English or American law to the duration of pregnancy, though
it is allowed that utero-gestation may be greatly prolonged. In a recent
case decided, the Lord Chancellor accepted a case where it was alleged
pregnancy had extended to 331 days. A child only five months old may
live, for a short time at all events. There is considerable difficulty
in many cases in fixing the date of conception. The data from which it
is calculated are the following: (1) _Peculiar sensations attending
conception_, which are not sufficiently defined to be recognized by
those conceiving for the first time. (2) _Cessation of the catamenia._
Other causes may, however, cause this; and, on the other hand, a woman
may menstruate during the whole period of her pregnancy. This datum also
gives a variable period, and may involve an error of several days or a
month, for the menses may be arrested by cold, etc., at one monthly
period, and the woman become pregnant before the next. (3) _The period
of quickening._ This, when perceived (which is not always the case),
also occurs at variable periods from the tenth to the twenty-sixth week.
(4) _A single coitus._ This does not, however, correspond to the time of
fertilization. Several days may elapse before the spermatozoa meet with
an ovum and fertilize it.

In Scotland a child born six months after marriage is legitimate, which
is allowing an ample margin.

XXX.--VIABILITY OF CHILDREN

A child may be born alive, but may not be viable, by which is meant that
it is not endowed with a capacity of maintaining its life. Speaking
generally, 180 days represents the lowest limit at which a child is
viable, but prolonged survival under these circumstances is the
exception. Many cases, however, have been recorded in which children
born at six months have been reared. The signs of immaturity and
maturity may be thus tabulated:

IMMATURITY. MATURITY.

Centre of body high