Possibly they were the result of a mixture between long-headed immigrants from eastern India, and round-headed Mongols from Indo-China and the rest of south-eastern Asia, from whom the present Malays are derived.
* * * * * We have completed our very rapid regional survey of the world; and what do we find?
By no means is it case after case of one region corresponding to one type of man and to one type of culture.

It might be that, given persistent physical conditions of a uniform kind, and complete isolation, human life would in the end conform to these conditions, or in other words stagnate.

No one can tell, and no one wants to know, because as a matter of fact no such environmental conditions occur in this world of ours.

Human history reveals itself as a bewildering series of interpenetrations.

What excites these movements?
Geographical causes, say the theorists of one idea.