But it should not be overlooked that such interesting deductions founded on language, its vocabularies and grammar, must not be pressed too closely. The state of civilization of the Indo-Germanic column, as thus ascertained, must needs have been inferior to that of the centre from which it issued forth. Such we observe to be the case in all migratory movements. It is not the more intellectual or civilized portions of a community which voluntarily participate therein, but those in whom the physical and animal character predominates. There may be a very rough offshoot from a very polished stock. Of course, the movement we are here considering must have taken place at a period chronologically remote, yet not so remote as might seem to be indicated by the state of civilization of the invaders, used as an indication of the state of civilization of the country from which they had come. In Asia, social advancement, as far back as we can discover, has ever been very slow; but, at the first moment that we encounter the Hindu race historically or philologically, it is dealing with philosophical and theological questions of the highest order, and settling, to its own satisfaction, problems requiring a cultivated intellect even so much as to propose. All this implies that in its social advancement there must have already been consumed a very long period of time. [Sidenote: Commingling of blood and of ideas.] But what chiefly interests us is the relation which must have been necessarily maintained between the intrusive people and those whom they thus displaced, the commingling of the ideas of the one with those of the other, arising from their commingling of blood. It is because of this that we find coexisting in the pre-Hellenic times the sorcery of the Celt and the polytheism of the Hindu. There can be no doubt that many of the philosophical lineaments displayed by the early European mythology are not due to indigenous thought, but were derived from an Asiatic source. [Sidenote: Climate-modification of Asiatic intruders.]