times yearly, producing each time from four to eleven young; and Mr. Harrison
Weir tells me of a case of eighteen young having been produced at a birth, all
of which survived. The ferret, though generally so closely confined, is more
prolific than its supposed wild prototype. The wild sow is remarkably
prolific; she often breeds twice in the year, and bears from four to eight and
sometimes even twelve young; but the domestic sow regularly breeds twice a
year, and would breed oftener if permitted; and a sow that produces less than
eight at a birth "is worth little, and the sooner she is fattened for the
butcher the better." The amount of food affects the fertility of the same
individual: thus sheep, which on mountains never produce more than one lamb at
a birth, when brought down to lowland pastures frequently bear twins. This
difference apparently is not due to the cold of the higher land, for sheep and
other domestic animals are said to be extremely prolific in Lapland. Hard
living, also, retards the period at which animals conceive; for it has been
found disadvantageous in the northern islands of Scotland to allow cows to
bear calves before they are four years old. (16/32. For cats and dogs etc. see
Bellingeri in 'Annal. des Sc. Nat.' 2nd series, Zoolog. tome 12 page 155. For
ferrets Bechstein 'Naturgeschichte Deutschlands' b. 1 1801 s. 786, 795. For
rabbits ditto s. 1123, 1131; and Bronn 'Geschichte der Natur.' b. 2 s. 99. For
mountain sheep ditto s. 102. For the fertility of the wild sow, see Bechstein
'Naturgesch. Deutschlands' b. 1 1801 s. 534; for the domestic pig Sidney's
edition of 'Youatt on the Pig' 1860 page 62. With respect to Lapland see
Acerbi 'Travels to the North Cape' English translation volume 2 page 222.
About the Highland cows see 'Hogg on Sheep' page 263.)

[Birds offer still better evidence of increased fertility from domestication:
the hen of the wild Gallus bankiva lays from six to ten eggs, a number which
would be thought nothing of with the domestic hen. The wild duck lays from
five to ten eggs; the tame one in the course of the year from eighty to one
hundred. The wild grey-lag goose lays from five to eight eggs; the tame from