profit to the farmer, as you get
more constitution and quicker growth; but for me, who sell a great
number of pigs for breeding purposes, I find it will not do, as it
requires many years to get anything like purity of blood again."[264]

Before passing on to Birds, I ought to refer to man, though I am unwilling
to enter on this subject, as it is surrounded by natural prejudices. It has
moreover been discussed by various authors under many points of view.[265]
Mr. Tylor[266] has shown {123} that with widely different races, in the
most distant quarters of the world, marriages between relations--even
between distant relations--have been strictly prohibited. A few exceptional
cases can be specified, especially with royal families; and these have been
enlarged on in a learned article[267] by Mr. W. Adam, and formerly in 1828
by Hofacker. Mr. Tylor is inclined to believe that the almost universal
prohibition of closely-related marriages has arisen from their evil effects
having been observed, and he ingeniously explains some apparent anomalies
in the prohibition not extending equally to the relations on both the male
and female side. He admits, however, that other causes, such as the
extension of friendly alliances, may have come into play. Mr. W. Adam, on
the other hand, concludes that related marriages are prohibited and viewed
with repugnance from the confusion which would thus arise in the descent of
property, and from other still more recondite reasons; but I cannot accept
this view, seeing that the savages of Australia and South America,[268] who
have no property to bequeath or fine moral feelings to confuse, hold the
crime of incest in abhorrence.

It would be interesting to know, if it could be ascertained, as throwing
light on this question with respect to man, what occurs with the higher
anthropomorphous apes--whether the young males and females soon wander away
from their parents, or whether the old males become jealous of their sons
and expel them, or whether any inherited instinctive feeling, from being
beneficial, has been generated, leading the young males and females of the
same family to prefer pairing with distinct families, and to dislike
pairing with each other. A considerable body of evidence has already been
advanced, showing that the offspring from parents which are not related are
more vigorous and fertile than those from parents which are closely
related; hence any slight feeling, arising