51 
the autumn, hut allowed them to freeze. At this season of the year, 
when a thin sheet of ice covered the lakes, the Eskimo often sank his 
caribou carcasses into shallow ponds, where no bears or foxes could 
disturb them before he recovered them a few weeks later and carried 
them away on his sled. The low temperature of the water appar- 
ently prevented the growth of bacteria, so that the meat remained 
perfectly fresh and wholesome. 
Frequent famines, and the hardships and accidents incidental to 
a migratory existence devoted to hunting and fishing, must have 
shortened the average span of life and caused a high rate of mortal- 
ity among all classes of the population, adults and children alike. 
The infant death-rate was appalling, partly through ignorance of 
some of the most elementary principles in child welfare, partly also 
through lack of proper food. The total absence of milk, except what 
the mother herself could provide, and the absence of cereals among 
all but the agricultural tribes, lengthened the period of lactation, be- 
cause no infant under the age of three years could assimilate a diet 
solely of meat and fish ; and prolonged lactation affected the fertility 
of the women, making the average famil}" small, although the Indians 
were natui'ally as fecund as Europeans.^ Social factors also helped 
to reduce the population, particularly the blood-feud, which was 
]:)revalent nearly everywhere, and the frequent wars between neigh- 
bouring peoples. In warfare many tribes spared no one, but massa- 
cred their enemies without regard to age or sex.- The Indians of 
the British Columbia coast enslaved men, women, and children, but 
even this practice checked the normal increase of the population, 
since marriage with slaves was considered discreditable. The 
Iroquoian system'" of adopting young captive women into the tribe 
and marrying them to the warriors was really based on a sound 
economic principle, and aided not a little in maintaining the strength 
of that warlike nation throughout a large part of its history. 
In spite of the social factors, however, the most important checks 
on natural increase undoubtedly arose from the character and uncer- 
1 Carega lias trifil to prove that the Eskimo were iihy.siologieally less fecund than Europeans, 
partly because of iiibrmling, partly because tlieir vitality was impaired by freuuent periods of malnutri- 
tion or starvation. Carega, G,; Alcuni dala demogratici sugli Esrpiimesi, Metron, vol. vii, No. 3, 
pp. 52-111 (Rome, 1928). HLs arguments seem hardly convincing, although they may hold good for one 
or two isolated communities. 
2 For a well-known historical instance, the massacre of an Eskimo band iiy the Chipewyans, See 
Hearne: Op, eit,, ch. vi. 
3 Practised occasionally by the plains' Indians also. 
