In a few thousand years the new species filled the region from Afghanistan to the China Sea, overran India, and penetrated far into the new Australasian continent. Its advance was less military than cultural. The remaining tribes of the First Men, with whom the new species could not normally interbreed, were unable to live up to the higher culture that flooded round them and over them. They faded out.

For some further thousands of years the Second Men remained as noble savages, then passed rapidly through the pastoral into the agricultural stage. In this era they sent an expedition across the new and gigantic Hindu Kush to explore Africa. Here it was that they came upon the subhuman descendants of the ship’s crew that had sailed from Siberia millions of years earlier. These animals had spread south through America and across the new Atlantic Isthmus into Africa.

Dwarfed almost to the knees of the superior species, bent so that as often as not they used their arms as aids to locomotion, flat-headed and curiously long-snouted, these creatures were by now more baboon-like than human. Yet in the wild state they maintained a very complicated organization into castes, based on the sense of smell. Their powers of scent, indeed, had developed at the expense of their intelligence. Certain odours, which had become sacred through their very repulsiveness, were given off only by individuals having certain diseases. Such individuals were treated with respect by their fellows; and though, in fact, they were debilitated by their disease, they were so feared that no healthy individual dared resist them. The characteristic odours were themselves graded in nobility, so that those individuals who bore only the less repulsive perfume, owed respect to those in whom a widespread rotting of the body occasioned the most nauseating stench. These plagues had the special effect of stimulating reproductive activity; and this fact was one cause both of the respect felt for them, and of the immense fertility of the species, such a fertility that, in spite of plagues and obtuseness, it had flooded two continents. For though the plagues were fatal, they were slow to develop. Further, though individuals far advanced in disease were often incapable of feeding themselves, they profited by the devotion of the healthy, who were well-pleased if they also became infected.

But the most startling fact about these creatures was that many of them had become enslaved to another species. When the Second Men had penetrated further into Africa they came to a forest region where companies of diminutive monkeys resisted their intrusion. It was soon evident that any interference with the imbecile and passive subhumans in this district was resented by the monkeys. And as the latter made use of a primitive kind of bow and poisoned arrows, their opposition was seriously inconvenient to the invaders. The use of weapons and other tools, and a remarkable coordination in warfare, made it clear that in intelligence this simian species had far outstripped all creatures save man. Indeed, the Second Men were now face to face with the only terrestrial species which ever evolved so far as to compete with man in versatility and practical shrewdness.

As the invaders advanced, the monkeys were seen to round up whole flocks of the submen and drive them out of reach. It was noticed also that these domesticated submen were wholly free from the diseases that infected their wild kinsfolk, who on this account greatly despised the healthy drudges. Later it transpired that the submen were trained as beasts of burden by the monkeys and that their flesh was a much relished article of diet. An arboreal city of woven branches was discovered, and was apparently in course of construction, for the submen were dragging timber and hauling it aloft, goaded by the boneheaded spears of the monkeys. It was evident also that the authority of the monkeys was maintained less by force than by intimidation. They anointed themselves with the juice of a rare aromatic plant, which struck terror into their poor cattle, and reduced them to abject docility.

Now the invaders were only a handful of pioneers. They had come over the mountains in search of metals, which had been brought to the earth’s surface during the volcanic era. An amiable race, they felt no hostility toward the monkeys, but rather amusement at their habits and ingenuity. But the monkeys resented the mere presence of these mightier beings; and, presently collecting in the tree-tops in thousands, they annihilated the party with their poisoned arrows. One man alone escaped into Asia. In a couple of years he returned, with a host. Yet this was no punitive expedition, for the bland Second Men were strangely lacking in resentment. Establishing themselves on the outskirts of the forest region, they contrived to communicate and barter with the little people of the trees, so that after a while they were allowed to enter the territory unmolested, and begin their great metallurgical survey.

A close study of the relations of these very different intelligences would be enlightening, but we have no time for it. Within their own sphere the monkeys showed perhaps a quicker wit than the men; but only within very narrow limits did their intelligence work at all. They were deft at finding new means for the better satisfaction of their appetites. But they wholly lacked self-criticism. Upon a normal outfit of instinctive needs they had developed many acquired, traditional cravings, most of which were fantastic and harmful. The Second Men, on the other hand, though often momentarily outwitted by the monkeys, were in the long run incomparably more able and more sane.

The difference between the two species is seen clearly in their reaction to metals. The Second Men sought metal solely for the carrying on of an already well-advanced civilization. But the monkeys, when for the first time they saw the bright ingots, were fascinated. They had already begun to hate the invaders for their native superiority and their material wealth; and now this jealousy combined with primitive acquisitiveness to make the slabs of copper and tin become in their eyes symbols of power. In order to remain unmolested in their work, the invaders had paid a toll of the wares of their own country, of baskets, pottery, and various specially designed miniature tools. But at the sight of the crude metal, the monkeys demanded a share of this noblest product of their own land. This was readily granted, since it did away with the need of bringing goods from Asia. But the monkeys had no real use for metal. They merely hoarded it, and became increasingly avaricious. No one had respect among them who did not laboriously carry a great ingot about with him wherever he went. And after a while it came to be considered actually indecent to be seen without a slab of metal. In conversation between the sexes this symbol of refinement was always held so as to conceal the genitals.

The more metal the monkeys acquired the more they craved. Blood was often shed in disputes over the possession of hoards. But this internecine strife gave place at length to a concerted movement to prevent the whole export of metal from their land. Some even suggested that the ingots in their possession should be used for making more effective weapons, with which to expel the invaders. This policy was rejected, not merely because there were none who could work up the crude metal, but because it was generally agreed that to put such a sacred material to any kind of service would be base.

The will to be rid of the invader was augmented by a dispute about the submen. These abject beings were treated very harshly by their masters. Not only were they overworked, but also they were tortured in cold blood, not precisely through lust in cruelty, but through a queer sense of humour, or delight in the incongruous. For instance, it afforded the monkeys a strangely innocent and extravagant pleasure to compel these cattle to carry on their work in an erect posture, which was by now quite unnatural to them, or to eat their own excrement or even their own young. If ever these tortures roused some exceptional subman to rebel, the monkeys flared into contemptuous rage at such a lack of humour, so incapable were they of realizing the subjective processes of others. To one another they could, indeed, be kindly and generous; but even among themselves the imp of humour would sometimes run riot. In any matter in which an individual was misunderstood by his fellows, he was sure to be gleefully baited, and often harried to death. But in the main it was only the slave-species that suffered.

The invaders were outraged by this cruel imbecility, and ventured to protest. To the monkeys the protest was unintelligible. What were cattle for, but to be used in the service of superior beings? Evidently, the monkeys thought, the invaders were after all lacking in the finer capacities of mind, since they failed to appreciate the beauty of the fantastic.

This and other causes of friction finally led the monkeys to conceive a means of freeing themselves for ever. The Second Men had proved to be terribly liable to the diseases of their wretched subhuman kinsfolk. Only by very rigorous quarantine had they stamped out the epidemic that had revealed this fact. Now partly for revenge, but partly also through malicious delight in the topsy-turvy, the monkeys determined to make use of this human weakness. There was a certain nut, very palatable to both men and monkeys, which grew in a remote part of the country. The monkeys had already begun to barter this nut for extra metal; and the pioneering Second Men were arranging to send caravans laden with nuts into their own country. In this situation the monkeys found their opportunity. They carefully infected large quantities of nuts with the plagues rampant among those herds of submen which had not been domesticated. Very soon caravans of infected nuts were scattered over Asia. The effect upon a race wholly fresh to these microbes was disastrous. Not only were the pioneering settlements wiped out, but the bulk of the species also. The submen themselves had become adjusted to the microbes, and even reproduced more rapidly because of them. Not so the more delicately organized species. They died off like autumn leaves. Civilization fell to pieces. In a few generations Asia was peopled only by a handful of scattered savages, all diseased and mostly crippled.

But in spite of this disaster the species remained potentially the same. Within a few centuries it had thrown off the infection and had begun once more the ascent towards civilization. After another thousand years, pioneers again crossed the mountain and entered Africa. They met with no opposition. The precarious flicker of simian intelligence had long ago ceased. The monkeys had so burdened their bodies with metal and their minds with the obsession of metal, that at length the herds of subhuman cattle were able to rebel and devour their masters.