Chap. 4.] 
GE^^EBATIOX OF MAN, ETC. 
139 
happens but that either the mother herself, or one, at least, of 
the twins perishes. If, however, the twins should happen to 
he of different sexes, it is less probable that both of them will 
survive. Pemale children are matured more quickly than 
males,^^ and become old sooner. Of the two, male children 
most frequently are known to move in the womb they mostly 
lie on the right side of the body, females on the left.^^ 
CHAP. 4. (5.) — THE GENERATION OF MAN ; UNUSUAL DURATION 
OF PREGNANCY ; INSTANCES OF IT FROM SEVEN TO TWELVE 
MONTHS. 
In other animals the period of gestation and of birth is fixed 
and definite, while man, on the other hand, is born at all sea- 
sons of the year,^^ and without any certain period of gestation ;^ 
for one child is bom at the seventh month, another at the 
eighth, and so on, even to the beginning of the tenth and 
eleventh. Those children which are born before the seventh 
month are never kno\^n to survive unless, indeed, they hap- 
27 This does not correspond with the fact, as it exists in our time ; a 
circumstance which may probably depend upon our improvement in the 
obstetrical art. Nor is the opinion, that both twins are less likely to live, 
if of different sexes, sanctioned by modern experience. — B. 
28 '^Feminas gigni celerius quam mares;" there has been much discus- 
sion among the commentators, both with respect to the meaning of these 
words, and the fact to which they are supposed to refer. Hardouin inter- 
prets the phrase, crescere, perfici, vigere, adolescere Cuvier translates 
it, les filles sont portees moins long-temps par leur mere." There is, 
however, no foundation for this opinion as to a difference in the period of 
the gestation. — B. 
29 There may he some ground for this opinion ; it is maintained by 
Aristotle in his Hist. Anim. — B. As also by Galen. 
This statement is made upon the authority of Hippocrates, Aphor. 
B. V. c. 48, and Aristotle, Hist. Anim. ; but is probably without founda- 
tion. — B. 
31 Animals have a certain period for generation, because they are more 
immediately affected by the seasons, whereas, in the human race, the arts 
of life render these fixed terms unnecessary. — B. 
33 Notwithstanding all the observations of the moderns, the question is 
scarcely decided respecting the length of time to which pregnancy may be 
prolonged. Cuvier says, that the experiments of Tessier have shewn, that 
there is a greater latitude in animals than had previously been supposed ; 
he also remarks, that the same animals when domesticated, become less 
regular in this respect than in the wild state. — B. 
23 Dalechamps has collected authorities to prove, that a child may 
