subject to the Vahuma.[632] The latter keep out of
sight, being inferior in civilization but greater in power. Von
Goetzen also met with the Vahuma as rulers over the Vahuta, i.e.
"belongers," as they called them.[633] The Arabs hold the negroes
of Borku in subjection and rob them of the date harvest.[634] In
other parts of the same district a nomad section rules over a
settled section of the same population.[635] Nomads hold
themselves to be the proper ones to rule.[636] The Hyksos's
invasion of Egypt is a case of the subjection of tillers by
nomads, attended by all the contempt of men on one grade of
civilized effort for those on another.[637] The combination of
the two, the nomads forming the ruling caste of military nobles,
forms a strong state.[638] The Tuaregs of the Sahara do not allow
the inhabitants of Kauar to raise vegetables or grains, but force
them to buy the same of them (the Tuaregs), which they bring to
them from the Sudan to buy salt, which the Kauar dwellers must
have ready.[639] The Akarnanians, in 1350, sold themselves to the
barbarians, in a body, in order to escape want.[640] The Masai
are another group of warriors and raiders. The Varombutta do
their hunting and tilling for them.[641] The Makololo hold the
Makalaka in similar serfdom, but the subjection is easy and the
servitude light, because the subject individuals can easily run
away.[642] The Hupa of California hold their neighbors in similar
subjection and in tributary servitude.[643] Other cases are
furnished by the Vanyambo, west of the Victoria Nyassa,[644] and
the Djur, who long served the Nubians as smiths.[645] It gives us
pleasure to learn that, about sixty years ago, the inferior
tribes on Uvea (Tai), of the Loyalty group, revolted against the
dominant tribe and nearly exterminated it.[646]

+273. Slavery and polygamy.+ Such instances show us the existence
in human nature of a tendency of stronger groups to exploit
weaker ones in the struggle for existence; in other words,
slavery or forced labor is one way in which, in elementary
civilization, the survival of the fittest group is brought about.
The slavery of individuals has not the same definite result on
the competition of life. "We find polygamy and slavery
continually at work dissolving the cohesion of old political
institutions in the old civilized races of Asia and