it might otherwise have had. The broad plain composing the greater part of the territory, though unfavorable for early progress, may prove to be advantageous after industrial advance has been made, for it permits easy means of communication. The most favorable topography from the point of view of communication seems again to be moderate homogeneity, - mountain chains which form barriers in early stages of development but which offer no serious obstacle to communication among advanced peoples. If barriers are numerous, or formidable, they keep people from uniting both socially and politically. Such areas are therefore likely either to be cut up into small political units, like the Balkan States, or, if actually united politically, they are liable to be weakened by jealousies arising from local differences. Conclusion. In conclusion it may be said that physical features have a real and important influence both on early and on advanced civilizations. Such features as natural resources, climate, topography, location, and ease of communication, have been discussed; but it is impossible to lay down any principle as to their relative importance. In some cases one seems to be the determining factor, and in other cases, another. Usually a favorable combination has been necessary for continuous development. The power of a physical factor may change as civilization develops; and that country is specially favored in which the early advantages of the physical environment do not turn to disadvantages as social life develops. The question of the relative degrees of influence of the physical environment upon primitive as compared with advanced peoples has received much attention. Some writers have maintained that, while the physical environment is undoubtedly of great importance in the development of early civilizations, it is of diminishing significance as civilization advances. But probably Miss Semple is more nearly correct when she says that civilized man is affected by a larger number of physical influences, but that no one of them ever has such a preponderating effect as it may have with primitive man. REFERENCES FOR COLLATERAL READING printed in Carver, Sociology and Social Progress, Ch. 10. Civilization and Climate. - World Power and Evolution. American History and its Geographic Conditions. CHAPTER IX INFLUENCES OF THE LOWER ORGANIC ENVIRONMENT Struggle with Lower Forms of Life is Both Direct and Indirect. 'Turning now to that part of the environment which consists of plant and animal life, we find a clear line of demarcation between the struggle side and the exploitation side of the process of adaptation. The struggle of man with the lower organic environment is of two kinds, direct and indirect. In the former, man himself is in danger and the struggle is for immediate supremacy. In the latter, though man is not directly attacked, both man and lower organisms struggle for the possession of something that is important for existence, usually the food supply. Primitive peoples, poorly equipped with weapons, found both the direct and the indirect struggles with lower organic life serious. Many of the lower animals are superior to man in size and strength; and he fought a winning battle with them only by means of his superior cunning or by force of numbers. Both primitive art and religion would seem to suggest the intimate and serious part which wild animals played in the life of savage tribes. In the indirect struggle with animals pastoral peoples undergo considerable losses from attacks of carnivorous animals, while agricultural peoples suffer from the depredations of herbivorous animals. The indirect struggle with vegetable life is chiefly for the possession of the soil. In tropical countries vegetation is so luxuriant that strenuous and continuous labor is required to keep the land cleared for cultivation and communication. Primitive man with nothing but rude stone tools was utterly unequal to the task, and where vegetation grows again so quickly even with modern instruments progress must be slow. Even in the less fertile colder climates the American Indians did not attempt agriculture where grass had made headway; they preferred wooded areas, where they girdled the trees to obtain sunlight, without attempting to cut them down, and planted in the free soil about their roots. Nowhere can man be said to have been victorious in the struggle with vegetable life before steel implements were invented. In modern times the most important form of the indirect struggle with vegetable life is that of the farmer against weeds. Weeds are a serious pest, not only because they absorb moisture and properties of the soil valuable to crops, but they invite insects and may also introduce disease. The burden placed upon agriculture in the United States from this source is estimated at one hundred million dollars annually. Among civilized peoples direct conflict with wild animals is not the serious problem it was with primitive man, though there are districts where the contest still survives. In India tigers are sometimes very destructive, in parts of Europe packs of wolves are greatly to be feared, and in India poisonous snakes are said to kill fifty thousand people annually. These last deaths however are due less to man's inability to exterminate snakes than to his reluctance to interfere with them for religious reasons. To modern peoples with means of protection at their disposal and with improved offensive weapons, attacks from wild animals are no longer a real menace. What was once a struggle for life has now become a mere sport. Indeed the struggle has become so one-sided that society occasionally finds it necessary to intervene to protect an animal species from complete extinction. Among civilized peoples the serious contest is no longer with animals which are their equals or superiors physically, but with the most diminutive forms of life. We no longer struggle against lions and tigers, but against flies, mosquitoes, and disease germs. Yet this apparently inglorious conflict does represent a life and death struggle, the issue of which has only recently turned in favor of man. The nature of the contest is clear enough. Man, the animal with the highest degree of individual development and a low rate of reproduction, is striving for supremacy over animals having the smallest degree of individual 1 Kelsey, Physical Basis of Society, p. 75. development but the highest rate of multiplication. Nature's two great methods of adaptation are in conflict, — intellect against numbers, individuation against generation. In a struggle of this kind it is not the poisoned arrow, nor is it the bullet, but rather the microscope, which will win the victory and ensure man's survival. This struggle with parasites and with the carriers of parasites is arduous because the enemy is often so infinitesimal that it is hard to discover; and, again, when it has been determined, its rate of multiplication is so rapid that there is great difficulty in eliminating it. Indeed, the lower the form of life the more difficult of elimination it seems to be. The Nature of Heterogeneric Selection. The struggle of man with animal and plant life gives rise to a new form of selection, which Pearson has called heterogeneric, a form which is doubtless responsible for a large part of the death rate. ornithologist has pointed out the fact that birds usually die a “tragic ” death. The same thing is however true of man, who also falls a victim to animals, though these are not of superior intelligence or even superior strength, for man encounters insidious attacks of myriads of enemies whose treachery he has never even suspected, or whose presence has not been revealed to him by any of his senses. Under these conditions the tragedy of man seems even greater than that of animals who succumb to attacks from superior forms of life. Heterogeneric selection cannot always be distinguished in practice from inorganic selection. Individuals who are weakened through imperfect adaptation to the physical environment often succumb to attacks of parasites, which they would have been better able to resist had their physical adaptation been better. For society the problem of heterogeneric selection, like that of inorganic selection, is whether its effect on progress is desirable or undesirable. Heterogeneric selection, like other forms of selection, is a method of adaptation, the adaptation being in this case to the flora and fauna of the environment. Individuals who are particularly susceptible to the attacks of micro-organisms tend to be eliminated, leaving those to survive who have greater powers of resistance. This process therefore tends to produce a race which is immune to the attacks of unseen parasites, or |