The highest results of the development of agriculture in tropical countries, unaided by secondary influences, seem to have been those existing in the highly fertile regions of Egypt and Babylonia at the opening of the historical period. The density of population in those countries, due to their prolific production of food stuffs, gave rise to considerably developed political and social institutions, and laid the foundations for a great subsequent advance under the influence of warfare, invasion, and the other more potent causes of human progress. Only for such ulterior influences the agriculturists of these countries would perhaps to-day remain dormant in the stage of mental progress they had attained ten thousand years ago. In considering the existing conditions of the forest nomads and the African agriculturists, it is not safe to credit them with the origination of all the arts and implements they possess. The negroes, for instance, have been for ages in more or less close association with the Pygmies, and may have taught them many things which they would not have attained through their own limited powers of thought. The bow and poisoned arrow are very likely original with them. They possess this weapon throughout the wide range from the African Hottentots to the Philippine Negritos, while it is not a weapon of the surrounding peoples. The spear is probably also original. The same cannot safely be said of their traps and snares for game. These seem beyond their power of invention, and may well have been taught them by the negro tribes. Their habitations, aside from the mere leaf shelters, had probably a similar origin. In Africa the huts doubtless had their model in those of the negroes. In the Philippines they are pile-supported bamboo huts of the pattern of those of the Malays. If, then, we take from the forest folk the arts taught them or imitated by them, we reduce them to a very low level of intellect and a remarkable paucity of products from their own powers of thought. Similar reasoning may be applied to the settled natives of Africa. For thousands of years past they have been in contact on their northern borders with civilized peoples, numerous immigrants have made their way into the country, and a considerable degree of amalgamation has very likely taken place. We cannot, therefore, safely credit them with all the arts and implements they possess nor with all their political and social progress. No doubt much came to them from without, much was taught them from within, and a mixture of blood with superior races may have aided considerably in improving their stock. We are justified, then, in their case as in that of the Pygmies, in believing that their stage of mental and social development is only in part original with them, and is largely due to the influences of education and amalgamation.