[will] generate a change of habits long before the period arrives.”[166] “An insufficient supply of food to any people does not show itself merely in the shape of famine, but in other more permanent forms of distress, and in generating certain customs which operate sometimes with greater force in the prevention of a rising population” than in the destruction of the risen.[167] Robertson the historian truly says, that whether civilization has improved the lot of men may be doubtful, but it has certainly improved the condition of women. Among the Indians and almost all savages, “servitude is a name too mild to describe their wretched state.” The hard life of the men kills their instinctive fondness for the women; the latter are therefore less likely to become mothers, while, if they do, their own hardships and heavy tasks are a great hindrance to nursing. It is not surprising that the surviving children are of good physique; none but the exceptionally strong could weather the cruel discipline of childhood.[168] In South America the difficulty of upbringing actually led to an enforced monogamy, as well as to late marriages and their not unfrequent accompaniment, irregularities before marriage. Such customs diminish numbers. But even the adult savages do not find life easy. They are not the men to think of providing for a rainy day; in the short moments of plenty they do not think of the long days of want. Intemperate living as well as the rigour and the accidents of a hunting life cut off numbers in their prime. They are subject to diseases and invent no remedies. Their acquiescence in dirt leads to pestilences, but they invent no sanitary reforms; and their thinly-peopled country loses its natural exemption from epidemics. Their wars are internecine, for they are largely prompted by sheer self-preservation, and the thought that if the one combatant lives the other cannot. Cannibalism itself was at first due to extreme want, though what occasional hunger had begun, hate perpetuated in a custom. This and the low cunning and mean strategy, due to a resolve to survive at all costs, are the prime inventions of the struggle for existence on these low levels. Such are the causes by which the numbers of the North American Indians are kept down to a very low figure; but, low as it is, the figure is high enough for the food. Apart from a difference in the standard of living, the proportion of population to food is similar over the inhabited world; and in the same neighbourhood or among cognate races it will be almost identical. A diminution in one Indian tribe, not being voluntary, will not be the cause of plenty to the survivors; it has been the effect of want, and it will simply weaken the collective force of the tribe in the struggle against others.[169]