and the variable states of magnetism and heat, which throw the combinations into slow though constant change. But with all your enlargement of data, turn them as you will, at the end of every passage which they explore, the _door of life_ is closed against them still; and though more than once it has been proclaimed that a way has been found through, it has proved that the living thing was on the wrong side to begin with. It is not true, therefore, that, from the two earlier stages of force, the ascent can be made to the vital level; the ethereal fire yet remains in Heaven; and philosophy has not stretched forth the Promethean arm that can bring it down. And if, once more, we make you a present of this third phase of power, and place at your disposal all that is contained beneath and within the flora of the world, still your problem is no easier than before; you cannot take a single step towards the deduction of sensation and thought: neither at the upper limit do the highest plants (the exogens) transcend themselves and overbalance into animal existence; nor at the lower, grope as you may among the sea-weeds and sponges, can you persuade the sporules of the one to develop into the other. It is again not true, therefore, that, in virtue of the convertibility of force, the possession of any is the possession of the whole: we give you all the forms but one; and that one looks calmly down on your busy evolutions, and remains inaccessible. Is, then, the transmigration of forces altogether an illusion? By no means; but before one can exchange with another, _both must be there_; and to turn their equivalence into a universal formula, _all_ must be there. With only one kind of elementary matter, there can be no chemistry; with only the chemical elements and their laws, no life; with only vital resources, as in the vegetable world, no beginning of mind. But let Thought and Will with their conditions once be there, and they will appropriate vital power; as life, once in possession, will ply the alembics and the test-tubes of its organic laboratory; and chemical affinity is no sooner on the field than it plays its game among the cohesions of simple gravitation. Hence it is impossible to work the theory of Evolution upwards from the bottom. If all force is to be conceived as One, its type must be looked for in the highest and all-comprehending term; and Mind must be conceived as there, and as divesting itself of some specialty at each step of its descent to a lower stratum of law, till represented at the base under the guise of simple Dynamics. Or, if you retain the forces in their plurality, then you must _assume_ them _all_ among your data, and confess, with one of the greatest living expositors of the phenomena of Development, that unless among your primordial elements you scatter already the germs of mind as well as the inferior elements, the Evolution can never be wrought out.[15] But surely a theory, which is content simply to assume