blind and helpless litter would have perished. By the marsupial modification the mother is enabled to carry her offspring with her in the long migrations necessitated by the scarcity of water." Mr. Owen adds-" These correlated modifications of maternal and foetal structures, designed with special reference to the peculiar conditions of both mother and offspring, afford, as it seems to me, irrefragable evidence of creative foresight." A difficulty attends this theory: the pouch is not possessed by all marsupials.

The great class of mammals had a small beginning, and made little or no advance during the vast Mesozoic time. In the Neozoic time existed that higher group which now has pre-eminence. Animals related to tapirs, bears, racoons, are among the oldest. The Miocene was the culminating age of mammalia: they were then largest and most numerous. The Deinothere was as much larger than our elephant as the elephant exceeds an ox; the skull, including snout, was five or six feet long; two large tusks grew out of the end of the lower jaw and pointed downwards. The most ancient beasts of prey are the feline, then the canidæ, latest the ursidæ. Relics of their predecessors we do not possess. The beast of the earth and cattle are the freely roving vegetable and flesh eating wild animals of the land, creatures of the marsh, the field, the forest, the plain. The Eocene and Miocene strata of North America are crowded with carnivora, ruminantia, pachydermata, rodentia, and non-ruminating creatures of the horse, rhinoceros, pig, tribes.

Heredity, or inheritance of the parents' nature, seems to be the natural cause of stability; and Adaptation one of the causes of modification or change in organisms. Structure and function being exposed to countless actions and reactions, from generation to generation, of ever-varying circumstances, the wonder is that we have not greater varieties, and that they are not mingled in utter confusion. There must be some deep and far-reaching law marvellously adjusting stability and instability, multiplication and extinction, that due equilibrium may be preserved. In every species, animal or vegetable, the

1 "Classification and Geographical Distribution of the Mammalia:" Richard Owen, F.R.S.

Many Paths of Life.

269

individuals are never quite alike; and in every species, even in every individual, there is a greater or less tendency to produce varieties. Some unknown energy sets bounds to these changes; and we are amazed that the simple egg-cell of the maternal organism, and a single paternal sperm-thread, transfer to the young the minutest bodily and mental peculiarities of both parents. The germ from which most mammals are produced is the 120th part of an inch in diameter, the same size as in man.

Doubtless, we may say of life-vires acquirit eundo. The original forms of it, whether few or many, were capable of development, and received it. Every new natural principle was to the preceding as a miracle, the animal a miracle to the vegetable, and man a miracle to the beast of the field. We have a right from science to infer that there is a law which provides for the origination of species, de novo, from unorganised matter, which is called into action by conditions and in a manner wholly unknown to us and inimitable. Life did not flow in an organic circle; some forms, for reasons unknown, being retarded; and other forms, ascending in many lines of development, brought in new existences. Every species seems to come into being at a certain definite time, and to disappear at another definite time; though there are few, if indeed any instances, in which we can safely fix the time for entrance or exit. This bringing in or creating of new things is our general notion of a miracle; and foretelling the new is our general idea of prophecy. All past variety of growth and development of power were figures of future advance, or allegory of forms to come; every low grade reappearing in the higher, as initial, subservient and supporting substance. On natural life is grafted intellectual life; on intellectual life, the spiritual and moral; on spiritual and moral, future life. Life, ascending in many various paths, is everywhere subjected to spirit; and life subjects and connects matter, as the crystallographer connects imponderable forces and polarity; the coarse or outside substance becoming, so to speak, the precipitate of inner and finer formations. There are worlds within worlds; infinity contains space, space comprehends matter, matter embraces life, life enfolds intelligence, intelligence is the breath of spirit.

Life-forms are classed according to the differences in structure. Heredity tends to conservation; and power of Adaptation, by circumstances to circumstances, tends to variety. Hence, offspring resemble their parents; but are never wholly alike either in form or in structure. The likeness preserves the identity of species, unlikeness tends to variety. Sometimes the variety arises in full force per saltum; but in every case there are determining causes, external, or internal, or both. Even a variety which approaches the nature of a monstrosity strives, Caliban-like, to reproduce itself; much more those which are better fitted to maintain the struggle for existence. Natural causes, acting through long ages of time, brought into existence from pre-existing life-forms all the varieties of life now on our globe; there is the constant introduction, throughout geological time, of new forms of life which do not appear to have been preceded by pre-existent allied types; the weaker, perishing; those excelling in strength, skill, agility, and best fitted to surrounding conditions, surviving. As a rule, the animals of lowest and simplest organisation have the longest range of time; the additional possession of minute dimensions is also in favour of their continuance. Large and highly organised animals, though long lived as individuals, rarely live long specifically.

The formation, according to law, of varieties and species from the common type of animal structure, is called "the Natural Origin of Species." The dying of unfavourable and the continuance of favourable specimens are designated "Natural Selection." So far, every breeder of sheep and pigeon fancier agrees with the philosopher. The argument may be carried into the domain of plants and flowers. Leaves become sepals and petals; sepals and petals grow into stamens, nectaries, ovaries, as is known to every practical florist and seedsman. Of the nature of the forces evoked we know nothing, nor can we account for the constant introduction of new life-forms, age after age, more and more like those now in existence. There is, however, a limit to varieties: as to those which are strictly species-" Each of them always 1 For examples, see H. Alleyne Nicholson's "Life History of the Earth," p. 373.

Variations from Primitive Type.

2

271

remains separated from the others by an interval which Nature cannot overstep."1 "It is one of the clearest facts in the animal as in the vegetable world; all races gradually reproduce and perpetuate themselves without mingling or confounding one with the other." It is put yet more forcibly— "No race will amalgamate with another: they die out, or seem slowly to be becoming extinct." Professor Huxley states "To sum up our knowledge of the ethnological past of man; so far as the light is bright, it shows him substantially the same as now, and when it grows dim, it permits us to see no sign that he was other than he is now.' In the same address he says-"Admit that Negroes and Australians, Negritoes and Mongols are distinct species, a distinct genus, if you will, and you may yet, with perfect consistency, be the strictest of monogenists, and even believe in Adam and Eve as the primeval parents of all mankind." So we may say with Sir Charles Lyell " There is no valid objection to the doctrine of the human race springing from a single pair." 5

"4

"5

Goethe was the first, Professor Helmholtz says, who laid down with precision and confidence, that all differences in the structure of animals must be looked upon as variations of a single primitive type, induced by the coalescence, the alteration, the increase, the diminution, or even the complete removal of single parts of the structure; the very principle, in fact, which has become the leading idea of comparative anatomy in its present stage. Dr. Darwin thinks "there is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one."7 Professor Huxley says—“ All existing species are the result of the modification of pre-existing species, and those of their predecessors; and it is probable, though not a necessary consequence of this hypothesis, that all living creatures have arisen from a single stock. . . . The vast series of extinct animals is not divisible, as it was once supposed to be, into

...

1 Isidore Geoffrey Saint-Hilaire, "Historie Naturelle Generale," iii. p. 210. 2 Prichard, "Natural History of Man," i. p. 17. Ethnological Journal, p. 98. "Antiquity of Man," xx. p. 385.

"Method and Results of Ethnology." Goethe's "Scientific Researches."

"Origin of Species," Edit. 4, p. 576.

distinct groups, separated by sharply marked boundaries. There are no great gulfs between epochs and formations-no successive periods marked by the appearance of plants, of water animals, and of land animals en masse." It is conceivable, though no case is certainly known of any animal or plant assuming the characters of a new species; and species may have been so constructed that, after a certain number of generations, they undergo either abrupt or gradual changes somewhat similar to those in embryological growth.

The theory of Lamarck groups organic matter under simple forms. Their first outlines, altered by time and circumstances, successively give birth to radiated creatures, to the inferior molluscs, to articulate animals, to the lowest fishes, then to man. "Exercising an organ gains development and extension which insensibly change it, until it becomes wholiy different. On the contrary, the faulty use of an organ impoverishes it gradually, and ends by destroying it." 2 Birds, ceasing to fly, lose the power of flight. "This atrophy reaches its climax in the snakes, . . . by the ribs and intercostal muscles having undertaken the work of the limbs." Mr. Owen writes-"I am constrained by evidence to affirm that in the vertebrate, as in the invertebrate series, there is manifested a principle of development through polar relations, working by repetition of act, and by multiplication of life-parts, controlled by an opposite tendency to diversify the construction, and enrich it with all possible forms, proportions, and modifications of parts, conducive to the fulfilment of a pre-ordained purpose and a final aim; these opposite yet reciprocally complemental factors co-operating to the ultimate result, with different degrees of disturbance, yet without destruction of the evidence of the typical unity." 4 Evidence may be multiplied to any extent. "Every cell, like every individual plant or animal, is the product of a previous organism of the same kind." "Unity of plan everywhere lies hidden under the mask of diversity of structure." In plainer words-"To study the succession of

1 "Criticism on the Origin of Species." 2 "Organisation des Corps vivants." "The Doctrine of Descent and Darwinism: " Oscar Schmidt. "Anatomy of Vertebratest," Introd. p. xxi.: Richard Owen, M. A., F.R.S. Comparative Physiology," p. 347: Dr. Carpenter.