Evolution, that is a progress from the comparatively simple to the more complicated, is a striking fact--I say comparatively simple advisedly, for even in the unicellular organism the processes are far removed from the absolutely simple. We do not know from what part of the organism the impulse to evolution comes. Here we meet with the same mystery which shrouds growth, its duration, its measure and its bounds. As the conception is lacking, a word has been found, viz., entelechy, which Driesch introduced into biology, the co-operation of all parts of the organism for the purpose not only of preserving it but also of making it more efficient in the matter of self-preservation and more perfect. A critical investigation of entelechy would involve the broaching of the whole question of life. It does not come within the scope of this work. I shall therefore content myself with a very few remarks. Entelechy works as if it were reasonable and acted with a set purpose. If you think it out exhaustively it forces you to the assumption that life is an intellectual principle, even in the protoplasm of the cell, long before there is any perceptible trace of consciousness; that this intellectual principle makes use of matter, builds it up, organizes it, moulds it into material and tools for construction, and sets up a mechanism in which and by which it develops itself. As far as we can see the purpose of life is life itself. Entelechy directs all the work of the organism in such a way that it becomes more and more capable of self-preservation, that its efficiency becomes greater, that it can absorb more of the outer world and can react more vigorously upon the outer world. In other words, life strives continuously to make its embodiments more permanent, securer, richer and more manifold. However, if we do not know how the impulse to evolution originates, we can at least form an idea of the mechanism of evolution. Fundamentally life consists in the absorption of cosmic movements or vibrations, and their transformation into another form of movement. The living cell is a machine which makes use of cosmic energy for physio-chemical work. Metabolism, warmth, electric manifestations, movement, and as their concomitant a graduated consciousness, are the result of this work which is carried out by cosmic energy in the cell power machine.