If the Ancients had better intellects than ours, the brains of that age must have been better arranged, formed of firmer or more delicate fibres, fuller of "animal spirits." But if such a difference existed, Nature must have been more vigorous; and in that case the trees must have profited by that superior vigour and have been larger and finer. The truth is that Nature has in her hands a certain paste which is always the same, which she is ever turning over and over again in a thousand ways, and of which she forms men, animals, and plants. She has not formed Homer, Demosthenes, and Plato of a finer or better kneaded clay than our poets, orators, and philosophers. Do not object that minds are not material. They are connected by a material bond with the brain, and it is the quality of this material bond that determines intellectual differences. But although natural processes do not change from age to age, they differ in their effects in different climates. "It is certain that as a result of the reciprocal dependence which exists between all parts of the material world, differences of climate, which so clearly affect the life of plants, must also produce some effect on human brains." May it not be said then that, in consequence of climatic conditions, ancient Greece and Rome produced men of mental qualities different from those which could be produced in France? Oranges grow easily in Italy; it is more difficult to cultivate them in France. Fontenelle replies that art and cultivation exert a much greater influence on human brains than on the soil; ideas can be transported more easily from one country to another than plants; and as a consequence of commerce and mutual influence, peoples do not retain the original mental peculiarities due to climate. This may not be true of the extreme climates in the torrid and glacial zones, but in the temperate zone we may discount entirely climatic influence. The climates of Greece and Italy and that of France are too similar to cause any sensible difference between the Greeks or Latins and the French.