During the immensely long old Stone Age to which Peroché assigns a period of some three hundred thousand years since the beginning of the Ghellian epoch, the pleistocene precursors underwent very few or slight specializations or developments, a fact due mainly to the moderate and unchanging character of the climate during this long period. Progress in the arts, however, there was, to such an extent that in some things the period has not been equalled. Of this character are the exquisitely wrought flints of the Silurian period, which cannot be reproduced now. Primitive man as he existed in the Stone Age had very little in common with the “primitive men” of today. There are savages today who represent, in a way, a degree of savagery and a remoteness from civilization that in some respects takes them farther down the social ladder than any of the Aryan race of the Stone Age. “No pure primitive race exists in any part of the world today.”[16] Contact with more advanced races has invariably produced, sometimes a good and sometimes an evil effect. Races are what climate, soil, diet, pursuits, and inherited character make them,[17] and the Aryan savages of the Stone Age had a different set of these conditions to face from the Negro savages of today. [Illustration: A WELL-CARED FOR ESKIMO INFANT (COURTESY OF MUSEUM OF NATURAL HISTORY, NEW YORK)] [Illustration: NATIVE EAST AFRICAN MOTHER AND INFANT (COURTESY OF THE MUSEUM OF NATURAL HISTORY, NEW YORK)] It is not surprising to find today a race that in many respects represents the Stone Age period of civilization, displaying, together with the most barbarous customs, a wide knowledge of the arts, indicating that there had been contact with some higher race or its representatives. Tribes grade into one another in the matter of culture so that it is hard to classify them.[18] A struggle for existence may leave its mark on an advanced tribe so that while it may in general retain prominent barbaric or primitive characteristics, it will, in every other regard but these, seem an advanced tribe. The Nigritans, for instance,[19] have learned from their neighbours, the Abyssinians and the Arabs, the use of iron; yet they have not arrived at the Stone and Bronze ages in culture, and show in their social relations and domestic habits none of the characteristics of the more advanced tribes. So in the treatment of children. Wherever the treatment of the child is at variance with the other customs or conditions of the race, it will almost invariably be discovered that the change is due to economic reasons or to contact with a stronger race. That it is this contact with higher races that has helped undeveloped races to advance, is the opinion of Sir H. H. Johnson.[20]