with all its achievements and possessions." The great difference between thought as we find it in man, and its forms among the lower animals lies in what psychologists have called "progressive thought." The animals advance but little in their thinking processes but rest content with those of their ancestors--their thought seems to have become set or crystallized during the process of their evolution. The birds, mammals and the insects vary but little in their mental processes from their ancestors of many thousand years ago. They build their nests, or dens, in almost precisely the same manner as did their progenitors in the stone-age. But man has slowly but steadily progressed, in spite of temporary set-backs and failures. He has endeavored to progress and improve. Those tribes which fell back in regard to mental progress and advancement, have been left behind in the race, and in many cases have become extinct. The great natural law of the "survival of the fittest" has steadily operated in the life of the race. The "fittest" were those best adapted to grapple with and overcome the obstacles of their environment, and these obstacles were best overcome by the use of the intellect. Those tribes and those individuals whose intellect was active, tended to survive where others perished, and consequently they were able to transmit their intellectual quality to their descendants. Halleck says: "Nature is constantly using her power to kill off the thoughtless, or to cripple them in life's race. She is determined that only the fittest and the descendants of the fittest shall survive. By the 'fittest' she means those who have thought and whose ancestors have thought and profited thereby. Geologists tell us that ages ago there lived in England bears, tigers, elephants, lions and many other powerful and fierce animals. There was living contemporaneous with them a much weaker animal, that had neither the claws, the strength, nor the speed of the tiger. In fact this human being was almost defenceless. Had a being from another planet been asked to prophesy, he would undoubtedly have said that this helpless animal would be the first to be exterminated. And yet every one of those fierce creatures succumbed either to the change of climate, or to man's inferior strength. The reason was that man had one resource denied to the animals--the power of progressive thought. The land sank, the sea cut off England from the mainland, the climate changed, and even the strongest animals were helpless. But man changed his clothing with the changing climate. He made fires; he built a retreat to keep off death by cold. He thought out means to kill or to subdue the strongest animals. Had the lions, tigers or bears the power of progressive thought, they could have combined, and it would have been possible for them to exterminate man before he reached the civilized stage.... Man no longer sleeps in caves. The smoke