making of function a sort of immaterial and independent entity which constructs a material organ in order to lodge within it. No such idea is to be found in all the works of Lamarck. He formulates his law in the following terms: "In every animal which is still undergoing development, the frequent and sustained use of any one organ increases its size and power, whereas the constant neglect of the use of such organ weakens and deteriorates it, so that it finally disappears."
In his expression of this law Lamarck insists on the fact that organization precedes function. He affirms only that function, i.e. action and reaction, modifies the organ; or, in other words, that organisms are modelled by the action of exterior forces acting upon them. It is in this sense only that function may be said to make an organ, but this mode of expression should be avoided, as it is apt to be misunderstood.
Astronomy teaches us that our globe was detached from the sun in an incandescent state, and geology asserts that this earth has passed through a period of long ages when its temperature was incompatible with the existence of life. It was only with the cooling of the earth crust that it was possible for living beings to make their appearance. Hence they must of necessity have been produced spontaneously from terrestrial material under the influences of chemical and physical forces. This opinion imposes itself on all who reflect and judge freely. In the same way the doctrine of evolution necessitates as a corollary the doctrine of spontaneous generation. The doctrine of evolution should reconstitute every link in the chain of beings from the simplest to the most complicated; it cannot afford to leave out the most important of all, viz. the missing link between the inorganic and the organic kingdoms. If there is a chain, it must be continuous in all its parts, there can be no solution of continuity.
Evolutionists like Lamarck and Haeckel admit spontaneous generation, not as the most probable, but as the only possible explanation of the phenomenon of life.
Lamarck shows us the apparition of living things at a certain epoch of the earth's evolution, and the gradual
development of more complicated forms as the conditions changed on the surface of the globe. Darwin shows how heredity and natural selection tend to accentuate the variations which are favourable to existence. Haeckel demonstrates the parallelism between ontogenesis and philogenesis—between the successive forms in the evolution of the embryo and the successive forms of the individual in the evolution of a race. These are great and admirable conquests of the human intelligence, they have demonstrated the first appearance and the progressive evolution of living beings; it now only remains for us to explain them.
The doctrine of evolution, while enforcing the fact of spontaneous generation and progressive evolution, gives us no hint as to the physical mechanism of such generation. It does not tell us by what forces, or according to what laws, the simpler forms of life have been produced, or in what manner differences of environment have acted in order to modify them. The doctrine asserts the simultaneous variations in organic forms and in the physical influences which produce them, but says
nothing as to their mode of action. The Darwinian theory shows how acquired variations are transmitted and accentuated by natural selection, but it says nothing as to how these variations may be acquired. In the same way we are in entire ignorance as to the physical mechanism of ontogenetic development, the evolution of the embryo.
The morphogenic action of diffusion produces osmotic growths of extreme variety. Most of these forms recall those of living things—shells, fungi, corals, and algæ. The analogy of function is quite as close as the resemblance of form. The study of osmosis, however, is as yet in its infancy, and osmotic productions vary with the physical conditions of chemical constitution, temperature, concentration, and the like. The study of the organizing action of osmosis on organic material has as yet been hardly attempted.