From age to age the population of earth varies considerably though within certain limits. At present, souls appear to be crowding in, which may continue for a while. At other times large portions of the earth may lie fallow and mankind be reduced in numbers. We have to be very careful not to stand in judgment upon peoples whose life-style may seem to us to be lacking in many of those comforts and other niceties which we consider necessary today. This is simply not true.
Mankind is very, very old indeed, many millions of years.
Human civilizations stretch back into legendary times. If we would study comparatively the myths and epics of mankind and give some credence to them we would find these old accounts describing civilizations on continents now sunken. These legends are the only memory we have of these older periods obscured by intervening catastrophes, natural and human. They have survived with all the races by oral tradition. Any written records would have been destroyed in the often violent periods that have intervened.