religious benediction of marriage
was not obligatory. Luther held that marriage should be purely civil,
but legal civil marriage was only introduced among us by the French
Revolution, while it had existed in remote times among the Peruvians,
Nicaraguans and others. Among certain races, marriages concluded
without _dot_, without ceremony, or without purchase, and even those
between different castes, are often regarded as concubinage.

FORMS OF MARRIAGE

Leaving aside hermaphrodites, such as the snails, in which each
individual has both kinds of sexual organs and plays the part of both
male and female, there are among animals with separate sexes five
forms of conjugal union:

(1). _Temporary or perpetual monogamy_, or marriage between one
individual of one sex and one of the other sex. This is the case with
most birds and mammals and many races of man.

(2). _Polygymy or polygamy_, or the marriage of one male with several
females. This occurs in ruminants, stags, fowls, and other animals, as
well as in some human beings; for example, the Islamites, negroes,
American Indians, Mormons, etc.

(3). _Polyandry_, or the marriage of one female with several males.
This is met with chiefly in the ants, in which each female is
generally fecundated successively by several males. In most of the
higher animals, the jealousy of the males renders polyandry
impossible. In man it is rare but exists among certain races.

(4). _Marriage in groups_, or marriage between several males and
several females. This singular custom is rare but exists in the Togas,
a tribe of savages. I am not aware of its existence among animals.

(5). _Promiscuity_, or free sexual intercourse between males and
females. This occurs in many animals, especially in the lower animals
in which the sexual instinct of the male is not associated with any
regard for the female or the progeny. Promiscuity is still more
natural when the female does not look after her young after she has
laid her eggs. Nevertheless, in most animals the female limits herself
to sexual intercourse before each brood, so that real promiscuity is
not so frequent as would at first appear. In man, on the contrary, it
attains its apogee in prostitution, which is the only absolutely
complete form of promiscuity. But the result of prostitution as
regards the preservation of the species, which is the proper object of
all sexual union, is absolutely destructive.

Polygamy or polygymy were lici