The consequences of the radically altered disease environment of North America created by the coming of the white man cannot be overestimated even though direct evidence for the early effects on the upper Santa Cruz River Valley Piman aborigines does not exist. On the other hand, the epidemic decimation of population in the centres of prehistoric civilization on the central Mexican plateau proceeding simultaneously with Spanish military conquest destroyed the various socio-political and theocratic elites so thoroughly in the south that the northern Pimans were left drifting insofar as 50cultural orientation was concerned. After centuries of looking southward for guidance in the correct and proper methods of social and religious behavior, and improved exploitative and other economic techniques, the northern Pimans were suddenly and without warning thrown entirely on their own resources. Historical behavior of the northern Pimans proves that these resources within the society have always been extremely meagre, and social sanctions exterior to the society have ever been necessary to initiate successfully and to implement social, religious or technological changes and prevent utter stagnation and deterioration. With the smashing of the fountainheads of cultural refinement and expanding complexity in the Mayan and Nahuatl and Zapotecan and Tarascan tribal states, the stream of culture from which the northern Piman peasants had drunk for centuries in a steady reformulation of their society and culture to approach civilized models rapidly dried up. As outside inspiration desiccated, the northern Piman emulators deteriorated, spurred on eventually by the goad of decimating epidemics.
In the south, military conquest accompanied or preceded population declines from infectious diseases. The apathetic psychological state of the conquered Indians was produced first by conquest and later reinforced by epidemic mortality. The two variables reinforced each other to the detriment of Indian survival. The most recent estimates of the loss of population suffered by the Indians in the most civilized 51regions indicate that where seven and one-third persons lived at the time of the conquest, only one survived by the time the population as a whole began to recover (Cook and Simpson 1948:38, 48). This ghastly diminution in manpower alone would have terminated the prehistoric position of the civilized tribes as generators of religious, political, social and economic innovations even without military conquest by the Spaniards. Moreover there is evidence suggesting that the losses both to diseases and in warfare were heaviest in the very elites which supplied native leaders-a fact of some significance in the ultimate conquest of the Aztec Empire. The energetic Aztec emperor who replaced Moctezuma II and drove the Spaniards from Tenochtitlan in bloody, broken disorder died from smallpox in 1520 (Díaz del Castillo 1956:328), and it was his younger successor who finally lost the city to the reinforced Spaniards. The ruler of Texcoco also succumbed to smallpox, and dying ended his resistance to the Spaniards (ibid., p. 349).
That either variable-military conquest or population declines due to epidemics-was capable of alone causing the death of native North American Indian cultures is indicated in the case history of the northern Pimans. Unconquered by Spaniards for two centuries after 1519, indeed not even in very close contact with them for at least one of those centuries, the northern Pimans nonetheless lived in a culture in decline in the early 1700's when the Spaniards began to live in the Santa Cruz River Valley. That decline set in 52primarily in response to the decline in available energy entailed in population losses during infectious epidemics reinforced by loss of sanctions for cultural improvement exterior to the society. Northern Piman culture was deteriorating in the 1700's because the northern Pimans were a dying people. Not until Spanish rule gave their culture a new direction and epidemics had taken their full population toll did the northern Pimans begin to recover a measure of cultural elan and to increase in numbers.
The mortality among the northern Pimans by the time the epidemics had run their course was probably not less than that in central Mexico, and perhaps greater. The worst effects of infectious epidemics apparently struck the northern Pimans somewhat later than the central Mexicans because the Pimans escaped the worst epidemics which occurred during their period of comparative isolation between 1531 and 1600. In the end the result was about the same: where over seven northern Pimans had lived in the year 1520, probably only one remained by the time the population began to increase again late in the eighteenth century.
The attitude toward infections and deaths therefrom displayed by the people of Tchoowaka in burning their homes and moving to a new ranchería site when a leader died in 1732 might have been expected to result in further fragmentation of northern Piman social life. Settlements could conceivably have been reduced ultimately to family groups for fear of contagion. Two other factors in northern Piman life arrested 53any such tendency however, and in fact reversed it so settlement size remained relatively constant although the number of settlements greatly decreased.
One factor was the danger of enemy attack, primarily from the southern Athapascans, omnipresent after the New Mexican Pueblo Revolt in 1680 triggered these rapacious displaced Plainsmen who were under heavy pressure from militarily superior Plains enemies, by supplying them with an abundance of horses, firearms and other goods plundered from the defeated Spaniards, and a sharp object lesson in Spanish vulnerability. Apache raids on northern Piman settlements became a very serious threat shortly after the Pueblo Revolt, adding to the high mortality rate and placing a very real premium upon large settlement populations as a protective measure, fostering consolidation of rancherías declining from raids or epidemics.
The other factor in maintaining northern Piman settlements at something like their aboriginal size while decreasing in number was the Spanish conceptual model for suitable colonial settlements of subject peoples-an intellectual model which had not existed in the Peninsula since the Romans conquered the resident barbarians (Foster 1951:317). This model envisioned large numbers of Indians living in compact urban communities, following a sedentary agricultural life which left them abundant time to attend mass, learn the catechism, and wait on newly-noble Spaniards beneath whose dignity it was to labor with their hands except in warfare. This model was 54enthusiastically and effectively urged upon the northern Pimans by missionaries, military and civil officials. The more acculturated northern Piman leaders accepted this model as possessing intrinsic value and actively aided in realizing it (Oacpicagigua Mar. 24, 1752).