Of all the populations of the world, the Peruvian is the most _vertical_ in its direction. Its line is due north and south; its breadth but narrow. The Pacific is at one side, and the Andes at the other. One is well-nigh as definite a limit as the other. When we cross the Cordilleras the Peruvian type has changed.
The Peruvians lie between the Tropics. They cross the Equator. One of their Republics--Ecuador--even takes its name from its meridian. But they are also mountaineers; and, though their sun is that of Africa, their soil is that of the Himalaya. Hence, their locality presents a conflict, balance, or antagonism of climatologic influences; and the degrees of altitude are opposed to those of latitude.
Again, _their line of migration is at a right angle with their Equatorial parallel_--that is, if we assume them to have come from North America. The bearing of this is as follows:--The town of Quito is about as far from Mexico due north, as it is from French Guiana due west. Now if we suppose the line of migration to have reached Peru from the latter country, the great-great-ancestors of the Peruvians would be people as inter-tropical as themselves, and the influences of climate would coincide with the influences of descent; whereas if it were North America from which they originated, their ancestors of a corresponding generation would represent the effect of a climate twenty-five degrees further north--these, in their turn, being descended from the occupants of the temperate, and they from those of the frigid zone. The full import of the relation of the lines of migration--real or hypothetical--to the degrees of latitude has yet to be duly appreciated. To say that the latter go for nothing because the inter-tropical Indian of South America is not as black as the negro, is to compare things that resemble each other in one particular only.
It is Peru where the ancient sepulchral remains have complicated ethnology. The skulls from ancient burial-places are preternaturally flattened. Consider this natural; and you have a fair reason for the recognition of a fresh species of the genus _Homo_. But is it legitimate to do so? I think not. That the practice of flattening the head of infants was a custom once as rife and common in Peru as it is in many other parts of both North and South America at the present day, is well known. Then why not account for the ancient flattening thus? I hold that the writers who hesitate to do this should undertake the difficult task of proving a negative: otherwise they multiply causes unnecessarily.