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this unity; and, in spite of their great and many outward differences, are arranged into six kingdoms.

1. PROTOZOA (paros, first (ov, life),

Are generally of a very minute size, composed of a nearly structureless, jelly-like substance. Animalcules, sponges, infusoria. They are not definitely segmented, have no nervous system, no digestive apparatus - beyond, occasionally, a mouth and gullet. The simplest, called monera, are small living corpuscles; nothing more than a shapeless, mobile, little lump of mucus or slime. Take a rhizopod: from the outside of this creature, which has no limiting membrane, numerous thread-like processes protrude. Originating from any point of the surface, each may contract again and disappear; or touching some fragment of nutriment, draw it, when contracting, into the general mass-thus serving as hand and mouth. This structureless body may join and become confluent with its fellow bodies; and, in brief, is at once all stomach, all skin, all mouth, all limb, and all lung.

2. CŒLENTERATA (xomos, hollow; TEPOV, intestine). Sea anemones, corals, sea jellies, sea firs. Most of them rise considerably above the protozoa in organization. They have a body-wall composed of two principal layers, an intestinal cavity, and a mouth leading into it. They have no organs of circulation, no nervous system-or but a rudimentary one; the mouth is surrounded by tentacles arranged in a star-like manner. The common hydra is commonly taken as a type of the lowest division. It can live when the

duties of skin and stomach have been interchanged by turning it inside out.

The

3. ANNULOIDA (annulus, a ring; ïdos, form). Sea-urchins, starfishes, land-stars, some internal parasites, as the tape-worm, with some minute aquatic creatures. digestive canal is completely shut off from the cavity of the body; there is a distinct nervous system; a system of branched water vessels, usually communicating with the interior; the body of the adult, often "radiate," is never composed of a succession of definite rings.

4. ANNULOSA.

Animals with bodies composed of numerous segments or

rings; and nervous system, forming a knotted cord, along the lower surface of the body. Worms, leeches, crabs, lobsters, spiders, scorpions, centipedes, insects.

5. MOLLUSCA (mollis, soft).

Shell-fish, snails, cuttle-fish, nautilus. Soft bodies, hard shells; no distinct segmentation of the body; and a nervous system of scattered masses.

6. VERTEBRATA.

Animals with a vertebral column. The body composed of definite segments, arranged longitudinally one behind the other; the main masses of the nervous system are placed dorsally. The limbs are never more than four in number. Fishes, amphibians, birds, mammals, man.

These modern classifications, with man at their head, are very simply arranged in the Divine account of the genealogical tree. We have moving creatures in the water, and creeping things on land; animals of length, birds, beasts, cattle, and man. Marine life, first created, is represented by the earliest fossils; and in the order of creation-plant, fish, bird, mammal, one generation hands a lamp of higher life to the next. To mark off the groups simply as beasts, birds, fishes, creeping things, is to make their differences of appearance, modes of life, and relative importance conspicuous. Creative energy, we may be sure, did not act by breach of natural law, but with power put forth uniformly; and in plant, fish, bird, mammal, there may have been no perceptible difference in their dawn of existence. They were not introduced collectively, or simultaneously; but at different periods in the day of life; and the earliest possessed characters in combination such as we now-a-days find separately developed in different groups of animals.

It is pleasant to have the kinship of all things authoritatively stated the water brought forth, and the earth brought forth; the vegetable had seed in itself, and the animal possessed life after his kind. Not only are all living animals reducible to five or six fundamental plans of structure; but amongst the vast series of fossil forms not one has yet been found with peculiarities entitling it to be placed in a new subkingdom. The animals belonging to the sub-kingdoms are

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framed upon the same fundamental plan of structure, and are also arranged in a series of groups. All the shell-fish, for example, are built upon a common plan-a plan representing the ideal mollusc.

In the kinship is individuality, and in the unity diversity. Every life possesses its own life. The primordial germs are essentially different, and tend toward the vegetable, or toward the animal, by such different lines that no plant becomes animal, no coral turns star-fish, no worm grows into leech, no cockle transforms into cuttle-fish. There are organisms with vital action not more lively than that of drops of oil fusing themselves together when they meet, and they attain no higher existence: fuse millions together yet no other animal is formed.

Trace the Process of Life.

All organisms arise out of structureless living matter, which in the primal state was not living at all. The essential principles of every change, or the active and moving part, no one knows how nor whence they come, enter and reside in the matter itself; and work, for the most part, from within. The earliest stages of organisms possess the greatest number of similarities. Somewhat further on, the characters are those belonging to a smaller number of organisms. At every advance, traits are acquired which successively distinguish group from group, and are finally narrowed into the highest species of finished structure. Thus were produced many varieties or species: creatures being modified by circumstances for circumstances: heredity and adaptation being the two great agents in influencing the mystery and variety of the living world of forms. In the finished structure of most advanced life we still find the same original or rudimentary matter out of which all organisms were created, and with which all are now built. Not only so, the screws, fastening the parts; the levers, raising them to a higher state; the pulleys, drawing them together; and the joints, knitting several limbs into one body; are constructed on common patterns. This fact, proving unity in the underlying energy, is a sparkle of the great truth that rules the universe: for example, the hydrogen atoms in the sun and planets vibrating

in unison with those on our planet, are like two tuning-forks set at concert pitch; and, awaking human response, we say"The mighty synthesis is proof that God is One."

The fact is capable of further development. Every process of initial life is the prophecy of an advanced life. From inorganic world-elements arise all organisms. A germ of life, even before it is large enough to be seen, contains in itself a special endowment-the invisible constructive potentiality of every organ. The first steps of life are in a path common to all, but quickly turn aside; and, by way of its own, every living creature arrives at a peculiar destination. In plants we have production and reproduction; in animals self-perception, self-control, and motion; in man self-consciousness, will, and moral power; the whole wrought by a deeper and more far-reaching energy than science can find any satisfactory explanation of, all the vital actions being, as the oscillations of a needle, moved by unseen influences from within and without.

The bringing forth of kind after its kind, that process by means of which new individuals are produced, and perpetuation of the species is ensured, presents many marvels. Some of the lowest and smallest animals are of both sexes,— "hermaphrodite." Others are non-sexual, and the young are produced by gemmation or fission.

Hermaphrodites are double-sexed individuals. Many plants, garden-snails, leeches, earth-worms, and various other worms, are of this order.

Gemmation (gemma, a bud) is the production of young by a bud or buds, usually on the outside, but sometimes on the inside of an animal. Thus new life is formed, which may either be completely separated from the parent, or remain connected with it, and form a stock or colony.

Fission (findo, I cleave) is the production of new beings by the cleavage or division of a primitive zoöid into two or more parts. This fission, occurring frequently, reproduces by tolerably rapid multiplication. An internal fission, or swarming, causes the death of the parent, and produces a vastly multiplied offspring.

In the Vertebrata and all high kinds of life, reproduction is

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always sexual, and the sexes are in different individuals. Most are oviparous, producing eggs from which the young are developed; but the higher vertebrates bring forth their young alive.

Until recent times it was thought that in every species the successive generations were alike, this is called homogenesis. It is now proved that in many plants, and in numerous animals, the successive generations are not alike,—this is called heterogenesis. The progeny, differing from the parents, produce others, like themselves, or like their parents, or like neither, but, eventually the original form reappears. There is no scientific explanation of this; we can only ascertain the varying order of it as seen in different creatures. In all cases of sexual or gamogenesis, there is reason to think that even among the lowest Protozoa, a fusion of two individualities is the process from which results the germ of a new series of individuals; so that in those humblest forms, which have no differentiation of sexes, the union is not of sperm-cells and germ-cells of the same individual, but union between those of different individuals. The power is mysterious, and the more so that the cells, or cradles of life, are not greatly specialized in mechanism, they rather seem unspecialized; yet, if there is no special arrangement to secure conditions of existence for different modes of multiplication, it is certain that arrangements which secure these special ends do continually establish themselves. No visible or mechanical property explains the profound distinction between the male and female reproductive elements; but in the union of these begins, at once, or on the arrival of favourable conditions, a new series of developmental changes; a process of cell-multiplication is set up, and the resulting cells aggregate into the rudiment of a new organism. The force by which two adjacent atoms attract or repel each other, their mode of exercise and law of variation, are incomprehensible. Every effort to understand the essence and origin of life leading to the Great Unknown, from whom all life has sprung, according to the patristic interpretation,—ő Yéyovev év aútậ wn v (Jno. i. 3, 4).

We may now briefly summarise some of the principal