Unity of Substance. ... 263 centre of identical nature; this a third, and so on repetitions of a primal complexly organised whole . . . are suggestive of operance akin to that of inorganic polar growths, as in a group of crystals, wherein each exemplifies the characters of the mineral or crystalline species, but is subject, like vital growths, to occasional malformation. . . . Growth by repetition of parts rapidly gives place to the higher mode of development by their differentiation and correlation for definite acts and complex functions."1 Hence, all organic matter has certain definite tendencies to formal character and development, which seem to be the impress of eternal fundamental energy. The endowment is there, whatever it may be ; and, because of this endowment, proceeds, from primordial germs, in no respect distinguishable, the whole variety of life. This startling fact disposes of the crystallisation doctrine of evolution, by taking the essential and distinctive facts of life far beyond the region that any theory is able at present to approach. We conclude, therefore, that the popular statement of Scripture covers accurate scientific reality: from primary "indifferenced" organic matter, proceeded undulations or rhythms, which progressing along straight or in circular or in other various complex lines, culminated in life. Every organism being a complex system of forces, and the higher organisms in almost infinite complication as compared with our powers of analysis. 3. Unity of Substance. All the forms of protoplasm which have hitherto been examined contain, when dead, the four elements: carbon, hydrogen, oxygen, nitrogen, and some sulphur. The flower of the field, and the blood which courses through our veins, the dense resisting mass of oak, and that transparent jelly which pulsates in the waters of a calm sea, are bound by one common tie, and are akin: "In wisdom God made them all" (Ps. civ. 24). The significance of this cannot be exaggerated; the occult subtle influences, making an essential distinction and difference where man finds none, are wonderful! When we think that the microscopic fungus, and the great Finner whale; all that wealth of foliage lying between the lowest Anatomy of Vertebrates," Pref. p. ix., x.: Richard Owen, F. R.S. 1 46 plant, and those trees which endure while nations and empires rise and fall; that Shakespeare, the genius, and midges, evoked by the sun; are all knit together by unity of substance; and have community of faculty through one Divinely fashioned material; we stand in awe of that varied interaction which makes Nature beautiful as the robe of the Almighty. Life-energy inspires this unity of substance, of form, of power, with variety in mechanical, chemical, vital operation; plying the tongue with exquisite movements to modulate the voice; using the nerves and muscles to send forth volitions; and, by the intellent, conversing with those invisible things of which the world is full. It introduces new objects and powers, overmasters recurring cycles of physical law, blending the welfare of sentient creatures with a plan going through all ages. Life, moreover, continually calls our moral sense and our intellect to new functions; and, by use of memory, as to the past, carries hope forward to the future; rendering bygone stages of existence platforms for that which is to come; so that we trace benign skill, stand in the presence of the Creator, and rejoice in words spoken long ago-"My substance was not hid from Thee, when I was made in secret, and curiously wrought in the lowest parts of the earth. Thine eyes did see my substance, yet being imperfect; and in Thy book all my members were written, which in continuance were fashioned, when as yet there was none of them" (Ps. cxxxix. 15, 16). We now advance from unity of principle to the process of variety : "Let the earth bring forth creeping thing." Insects were in the Devonian forests. Ancestors of our modern dragon-flies flitted with broad-veined wings, and their larvæ dwelt in the stagnant waters. One marvellous Orthoptera had netted wings attaining an expanse of seven inches. A kind of grasshopper, with a cricket-like chirp, raised the first insect music known. Cockroaches are of an old family, being found in the Carboniferous age with insects belonging to three of the orders into which modern insects are arranged. Shad-flies, weevils, millipedes, scorpions, spiders, are also of The Process of Variety. 265 the Carboniferous age. The compound facetted eyes of insects were as perfectly developed then as now. Of the two oldest land-snails-one is elongated, the other rounded. In this age or earlier, they emerged from the waters, moved on the land, and breathed air. The oldest known fossil butterfly seems to have relationship with some of the living butterflies of tropical America. In the Neozoic ages appear nearly all the orders of insects. They are of later origin, as Scripture declares, than the moving things of the waters. There is a scientific hypothesis that their progenitors were crustacea. The origin, division, and development of life, appear to have been in this order of progress-Plants reduced special elements, existing in gaseous and watery combination, to a solid form. Animals, deriving their forces directly or indirectly from plants, carried the transformation a step further. All the structural and functional motions of every organism being an advance from the motions of simple molecules, to those of compound molecules, and from these to those of masses. For example: all sea-snails are united by well-nigh numberless intermediate forms, and seem to have been the progenitors of fresh-water and land snails. The celebrated and various snails of the Stuben Valley, near Steinheim, in Würtemburg, whose snow-white shells constitute more than half the mass of the Tertiary limestone hills, exceed twenty different species; but the extreme forms are linked by so many which are intermediate, lying regularly above and beside one another, that their pedigree is easily traced. The historical succession is generally indicated: (1) in the palæontological history of organisms, furnished by fossils in their adaptation to those various changes in the earth, of which increase or decrease of temperature was the master fact affecting climate, food, land, and sea level; (2) in the history of individual organisms; (3) in the comparative anatomy of kindred organisms. These are the three main facts which prove that a marvellous process of adaptation has been in operation from the very beginning. For example, the Nummulites, whose shells, the size of a lentil, form nearly whole mountains in the Alpine system of Europe, and deposit thousands of feet in thickness in Africa and Asia, possess a house with many little chambers artistically ordered. The Polythalamia have shell-chambers wound round one another in a spiral line and great variety of exquisite forms. These little palaces of beauty, regular structure, elegant execution, are the product of a slimy, formless, living mass; and various, as their products, are the builders themselves. The differences, imperceptible in their chemical composition and physical construction, are brought plainly into view by the variety of their constructed habitations. As the chasm between creeping thing of the land and swarming thing of the sea is bridged by intermediate forms; so, between fish and animal of the land, come those amphibia of which ancient days afforded gigantic examples. Are we then to conclude that the land was colonised from the water? We may smile at those who assert that every foot comes from a fin, and that fish by gaping developed lungs; but as twice a day, in the rise and fall of the tide, some plants and animals have a twofold kind of life; those only touched by the highest tides, and those never uncovered but at lowest ebb, having intervals varying both in frequency and duration; it is easy to think of an advance of life from the sea to possess and replenish the land. Heredity from the water might be so acted upon through adaptation by land, that at last animals could wholly forsake the one for the other. The mud-fish is an example of transition into amphibia, and the tailed forms of amphibia are the most ancient. Tritons are amphibious animals, akin to frogs; and, like them, in an early stage, possess gills, by means of which they live and breathe the air that is dissolved in the water. At a later stage, like frogs, they leave the water, lose their gills, and are able to breathe with their lungs; but if, by being shut up in a tank, they cannot leave the water, they retain their gills. The gilled salamander, Axolotl (Siredon pisciformis), generally remains all its life in the water; but at the Zoological Garden, in Paris, not long ago, a small number crept out of the water, from the many hundreds of their fellows, on the dry land, lost their gills, and became gill-less salamanders-breathing only through their lungs. Salt-water crustacea and fish also live in the great fresh-water lakes of the world. Structural Changes. 267 This subjection to circumstances causes structural changes in the properties of already formed parts; but, within any assigned time, these changes fall within narrow limits; and so soon as the normal state is re-established, the organ and organism fall back to their original condition. Structure, handed down by heredity, is indeed liable to variations of considerable magnitude; in part by the individual, and in part by involved influences producing functional adaptations; but only power from without, acting within, can produce what is not inherent in the organism; and in no other way can we find a satisfactory explanation for the continual introduction throughout all geological time of those new forms of life, which do not appear to have been preceded by pre-existent allied types. There exists some other deeper, wider-reaching law than evolution as commonly taught. As to artificial acquirements, plants and animals when neglected relapse to their original wild forms; and mutilations of the bodythough continued from generation to generation, as nose and ear piercings, misshapings of the foot-as among the Chinese, and circumcision-as by the Jews, are not transmitted. However much the lower forms of life mingle; and the outward grades of fish and amphibia, marsupial and mammal, approach one another; distinct provinces of marine and terrestrial life are always maintained. The marsupial form, so akin to the reptile and amphibian, preceded the other mammalia in time. Of the Mesozoic species all are marsupial, small, of low grade, and allied to the monotremata in their lowest structures; but not lower than some now existing. Their low position may be associated with the habit of limiting the exercise of active-life faculties to the period of night's obscurity. The mother nurses her young in a tegumentary pouch, where they remain suspended to the teats, and are safely carried for a period nearly answering to that of uterine life in the higher mammals. Where great want of water exists; and, in dry seasons, rivers are converted into pools few and far between; in such a climate, at such a time, an ordinary non-marsupial animal like the wild cat or fox, having deposited her young, would travel far to quench her thirst. "Before she could return her |