Darwin started with the fact that breeders of animals and growers of plants, having at their disposal a large number of varieties, always diverging somewhat from each other, choose individuals possessing characteristics which they desired to strengthen, and use only these for procreation. In this manner the desired characteristic is gradually made more prominent, and the breeder appears to have obtained a new species. Similar conditions are supposed to prevail in Nature, only that there is lacking the selecting hand of the breeder. Here the so-called principle of Natural Selection holds automatic sway by means of the Struggle for Existence. All the various forms of life are warring for the means of subsistence, each striving to obtain for itself the best nourishment, etc. In this struggle those organisms will be victorious which possess the most favorable characteristics; all others must succumb. Hence those only will survive which are best adapted to their environment. But between those which survive, the struggle begins anew, and when the favoring peculiarities become more pronounced in some, (by chance, of course) these in turn win out. Thus Nature gradually improves her various breeds through the continued action of a self-regulating mechanism. Such are the main features of Darwinism, its real kernel, about which of course,--and this is a proof of its insufficiency,--from the very beginning a number of auxiliary hypotheses attached themselves. Darwin's theory sounds so clear and simple, and seems at first blush so luminous that it is no wonder if many careful naturalists regarded it as an incontrovertible truth. The warning voice of the more prudent men of science was silenced by the loud enthusiasm of the younger generation over the solution of the greatest of the world-problems: the genesis of living beings had been brought to light, and--a thing which admitted of no doubt--man as well as the brute creation was a product of purely natural evolution. The doctrine which materialism had already proclaimed with prophetic insight, had at length been irrefragably established on a scientific basis: God, Soul and Immortality were contemptuously relegated to the domain of nursery tales. What further use was there for a God when, in addition to the Kant-Laplacian theory of the origin of the planetary system, it had been discovered that living organisms had likewise evolved spontaneously? How could man who had sprung from the irrational brute possess a soul? And thus, finally, disappeared the third delusion, the hope of immortality. For with death the functions of the body simply cease, as also do those of the brain, which people had foolishly believed to be something more than an aggregation of atoms. The body dissolves into its constituent elements and serves in its turn to build up other organisms: but as a human body it all turns to dust nor 'leaves a wrack behind'. Thus Darwinism was