There is no human being so degraded, so brutish, in whom a twofold instinct, if I may be permitted so to call it, is not manifest; the instinct which incites to the gratification of material wants, and that which leads to higher aspirations. The degree of intensity of either of these two is the first and principal measure of the differences among races. In none, not even in the lowest tribes, are the two instincts precisely balanced. Among some, the physical wants or animal propensities preponderate; in others, these are subordinate to the speculative tendencies--the cravings for the abstract, the supernatural. Thus, the lowest of the yellow races seem to me to be dominated rather by the first, the physical instinct, without, however, being absolutely deprived of all capacity for abstractions. On the contrary, among the majority of the black races of corresponding rank, the habits are less active than pensive; imagination there attaches greater value to the things of the invisible than to those of the visible world. I do not thence deduce any conclusion of superior capacity for civilization on the part of those latter races over the former, for history demonstrates that both are equally insusceptible to attain it. Centuries, thousands of years, have passed by without either of them doing aught to ameliorate their condition, because they have never been able to associate a sufficient number of ideas with the same number of facts, to begin the march of progress. I wish merely to draw attention to the fact, that even among the lowest races we find this double current differently constituted. I shall now follow the ascending scale. Above the Samoyedes on the one hand, and the Fidas and Pelagian negroes on the other, we must place those tribes who are not content with a mere hut of branches, and a social condition based upon force only, but who are capable of comprehending and aspiring to a better condition. These are one degree above the most barbarous. If they belong to the first category of races--those who act more than they think, among whom the material tendency predominates over that for the abstract--their development will display itself in a greater perfection of their instruments of labor, and of war, in a greater care and skill in their ornaments, etc. In government, the warriors will take precedence over the priests; in their intercourse with others, they will show a certain aptitude and readiness for trafficking. Their wars, though still characterized by cruelty, will originate rather in a love of gain, than in the mere gratification of vindictive passions. In one word, material well-being, physical enjoyments, will be the main pursuit of each individual. I find this picture realized among several of the Mongol races, and also, to some extent, among the Quichuas and Azmaras of Peru.