The familiar comparison of an organism to a machine has given rise to very serious errors in regard to the former, and has, of late, been made the base of false dualistic principles. The modern "machine-theory of life" which is raised thereon demands an intelligent design and a deliberate constructing engineer for the origin of the organism, just as we find in the case of the machine. The organism is then very freely compared to a watch or a locomotive. In order to secure the regular working of such a complicated mechanism, it is necessary to arrange for a perfect co-operation of all its parts, and the slightest accident to a single wheel suffices to throw it out of gear. This figure was particularly employed by Louis Agassiz (1858), who saw "an incarnate thought of the Creator" in every species of animal and plant. Of late years it has been much used by Reinke in the support of his theosophic dualism. He described God, or "the world-soul," as the "cosmic intelligence," but ascribes to this mystic immaterial being the same attributes that the catechism and the preacher give to the Creator of heaven and earth. He compares the human intelligence which the watch-maker has put into the elaborate structure of the watch with the "cosmic intelligence" which the Creator has put in the organism, and insists that it is impossible to deduce its purposive organization from its material constituents. In this he entirely overlooks the immense difference between the "raw material" in the two cases. The "organs" of the watch are metallic parts, which fulfil their purpose in virtue only of their physical properties (hardness, elasticity, etc.). The organs of the living organism, on the other hand, perform their functions chiefly in virtue of their chemical composition. Their soft plasma-body is a chemical laboratory, the highly elaborate molecular structure of which is the historical product of countless complicated processes of heredity and adaptation. This invisible and hypothetical molecular structure must not (as is often done) be confused with the real and microscopically discoverable structure of the plasm, which is of great importance in the question of organization. If one is disposed to assume for this molecular structure a simple chemical substance, a deliberate design, and an "intelligent natural force" for cause, one is bound to do the same for powder, and say that the molecules of charcoal, sulphur, and saltpetre have been purposively combined to produce an explosion. It is well known that powder was not made according to a theory, but accidentally discovered in the course of experiment. The whole of this favorite machine-theory of life, and the far-reaching dualistic conclusions drawn from it, tumble to pieces when we study the simplest organisms known to us, the monera; for these are really organisms without organs--and without organization!