life bring to the front variations previously useless, a slight change often causing great results.

The fittest to survive is not necessarily the one most perfect ideally, but rather the one best adapted to, and most in harmony with, the environment at the time. To be too far ahead of the times is far more fatal, as regards worldly prospects in human society, than to be conspicuously behind them; for in the latter case the individual is pitied and allowed the crumbs of charity; in the former he is regarded with suspicion and starved. This may constitute a consoling thought to those who are temporarily out in the cold, and who see the place they covet occupied by manifestly inferior men.

COMPARISON OF NATURAL AND ARTIFICIAL SELECTION.-In comparing natural with artificial selection we meet with the same principles, and yet domestic races differ from natural ones. The reason of this is that man selects and propagates modifications solely for his own advantage or pleasure, and not for the creature's benefit; he always tends to exaggerate, to go to the extreme point of selecting useful or pleasing qualities. Races of animals are thus produced which would be incapable of independent existence; for instance, the prize-pig, which has to be fed with a spoon like a baby, would have a poor chance of existence in the wilderness; and races such as the Italian greyhound, the Fantail pigeon, hornless bulls, or the bull-dog of our dog shows, could not survive unless artificially protected.

Artificially-bred animals and plants are in fact in a condition of unstable equilibrium, and have a tendency to revert or slip back to a former and more stable condition, and are kept with difficulty at the stage they have reached. This is well seen in the tendency which crossed pigeons have to revert to the ancestral stage of the blue rock-pigeon. We may illustrate this point by a simple mechanical comparison.

A pack of cards lying on a table are in a condition of stability, and they may be taken to represent the normal or ancestral condition. If now the cards are built up to form a pagoda they are eminently unstable, although forming a more imposing structure, and are liable to collapse with the slightest touch, and revert to their former condition of stability. So the artificially-produced pigeons are much more imposing birds than the blue rock-pigeon, but they are in a condition of great instability, and readily revert to the ancestral condition.

Natural selection, on the other hand, acts, not for the good of man, but for the good of the species, and tends to preserve, develop, and perpetuate all characters which will give the species an advantage in the struggle for existence. There is no known instance of an animal or plant having either structure or instinct developed in order to benefit another species. Every species is for itself and for itself alone.

LECTURE III

THE ARGUMENT FROM PALEONTOLOGY

In the first lecture we discussed the theory of Evolution, which claimed that animals now living are the descendants of those that lived formerly. We found the objection to the theory to be that animals which lived formerly were unlike those now living, and therefore that modification was necessary. In the second lecture, we saw how this objection was met by the theory of Natural Selection, and that causes were shown to be in existence not only competent to give rise to modification, but inevitably leading to it.

Let us now test this theory by seeing whether or not it is in accordance with the facts with which it has to deal. There is no possible doubt as to which series of facts we must deal with first. We must unearth these ancestors, put them in the witness-box, examine and cross-examine them, and see whether they support our case or not.

Let us first examine the Crust of the Earth, and its great division into Stratified and Igneous rocks. A headland, for example, consists of stratified rocks ; the waves eat away the shore, and the cliffs fall in ; streams carry down the mud and sand ultimately into the sea, where it is deposited in a plane over the sea-bottom. The nature of the deposit will depend on the source of the supply. If we ask how and why the cliff is stratified, the cliff itself will tell us. The stratified condition is due to deposition under water. Igneous rocks are intrusive and are caused by the volcanic heat of the deeper parts of the earth.

The crust of the earth is made up of sedimentary or stratified rocks deposited one above another, the most recently formed being at the top. Their position may be subsequently disturbed, yet the general relation can usually be determined. Geologists find the sequence to be much the same, and to show general agreement in all parts of the earth, so that the same names can be employed.

Particular deposits may be thicker or thinner and of variable nature in different localities, or absent altogether. To interpret the crust of the earth we must read it as a history of the earth in successive chapters, like successive centuries or ages in the history of mankind. The chief differences are that it consists of several chapters of unequal length, of which there is no means of determining the absolute age or duration, separated by gaps about which we have no record whatever. The history of these times is revealed by fossils, “imprints on the pages of time," which can be compared to the descriptions and drawings in the written records of man. Bones, teeth, shells, and other hard parts are often found in extraordinarily perfect condition. These records tell us, for example, that but a short time ago, geologically speaking, the lion, bear, rhinoceros, mammoth, and hippopotamus lived in Britain.

This evidence is of great importance, for it consists of real remains of former inhabitants of the earth, who stand in the same relation to the present fauna as our Saxon or Norman ancestors do to ourselves; that is, they are the remains of the actual ancestors of living animals, and must include among them, were our collection complete, such ancestors of all living animals. This is evidence of peculiar value, and there is no gainsaying it. The true nature of fossils was neglected and greatly misunderstood until the early part of the present century; but since the time of Cuvier fossils have been collected diligently, and large numbers have been obtained from all parts of the earth. It is now known that the fossil Mollusca are considerably more numerous than those now living on the earth, and probably fossil mammals are almost as numerous as recent forms. The age of fossils cannot be determined absolutely; their relative age is, however, known, and we are able to draw up tables giving the order and sequence of events, though not the actual dates; sequences, moreover, that will apply not merely to one, but, with certain reservations, to all parts of the globe.

In order to learn the lesson taught by fossils let us take those found in England at different periods.