the sides of the body, which readily open to give them passage, and quickly heal; but in most instances of such kind of spontaneous evolution, channels are provided, through which they find their way to a separate existence.

These are some of the extraordinary modes by which the species is continued while the individual perishes, affording us a new and striking proof, that, though the analogies of Nature are preserved with remarkable regularity in all the higher species of existences, it is not because the Creator fails in resources and expedients, but because some wise plan of his government has induced him to restrict his creative power as regards these classes, to certain forms and types, while, in the less complicated organizations, he has found it expedient to take greater latitude. Nothing can be more curious and instructive than the view which the microscope has discovered to us, of that busy world of living beings, which lies beyond the sphere of our unassisted vision, so incalculable in their numbers, so diversified in their forms, so opposite from our experience in their modes of propagation, and their means of subsistence; and yet so wonderfully harmonizing, amidst all their vast anomalous varieties, with the more general analogies with which our senses have made us conversant, as to indicate, most unequivocally, the contriving mind and plastic hand of One Infinite Intelligence.

FOURTH WEEK-WEDNESDAY.

REPRODUCTION AMONG THE HIGHER ORDERS OF ANIMALS.

In ascending from the lower and less complicated forms of animal existence, to higher orders, we find the mode of reproduction more uniform, or at least more strictly confined to a single type, though still various and peculiar, in different species, with regard to matters of subordinate detail. In all the more perfect animals, reproduction takes place by means of a seed, or ovum, which is a process essentially different in its nature, as well as in the mode

of operation, from those already described. The developement of the germ takes place in one or other of the four following ways.

1. The ovum, when defended by a firm envelope, which contains a store of nutriment, is termed an egg, and is deposited in situations most favorable for the developement of the embryo, and also for its future support, when it emerges from the egg. Birds, as is well known, produce eggs which are encased in a calcareous shell, and hatch them by the warmth they communicate, in sitting on them with unwearied constancy. All animals

which thus lay eggs are termed oviparous.

Such

2. There are a few tribes, such as the viper and the salamander, whose eggs are never laid, but are hatched in the interior of the parent, so that they bring forth living offspring, although originally contained in eggs. animals are said to be ovo-viviparous. There are other tribes, again, which, according to circumstances, are either oviparous, or ovo-viviparous. This is the case with the shark.

3. Viviparous animals, are those in which no egg, properly so called, is formed; but the ovum, after passing through the oviduct, sends out vessels which form an attachment to the interior of a cavity in the body of the parent, whence it draws nourishment, and therefore has attained a considerable size at the time of its birth.

4. Marsupial animals, are those which, like the kangaroo and the opossum, are provided with abdominal pouches, into which the young, born at a very early stage of developement, are received, and where they are nourished with milk secreted from glands contained within these pouches. As the young, both in this and the last case, are nourished with milk prepared by similar glands, or mamma, the whole class of viviparous and marsupial animals has received, from this characteristic circumstance, the name of Mammalia.*

The varieties, now mentioned, in the means by which the first processes of reproduction are effected, are neither accidental nor capricious. They are adaptations of re

* Roget's Bridgewater Treatise, vol. ii. pp. 597, 598.

markable wisdom, connected always with peculiar conditions, either in the state or structure of the organized beings in which they occur. They are parts of a system, which is perfect in its various functions and relations, and admirably suited to fulfil the object in view. We may not always be able to trace the peculiar bearings of this system in all its branches; but, in general, it is open, at least in its great features, to human research; and, even where it is more recondite, there are still circumstances of obvious adjustment, which enable us confidently to say, that here are indications of admirable contrivance and forethought.

It is but a small portion, however, after all, that we can perceive of Creative Intelligence; because our ignorance continually interferes with the researches we make in any direction. All is full of wise adaptation and contrivance, so far as we can trace, and every new discovery of the properties and relations of things, affords us a further insight into the beautiful designs of an all-pervading Mind; while the further we penetrate, our convictions become the stronger, that we are yet but at the surface, and that what remains behind, could we but dive still deeper, would only furnish us with more irrefragable evidence of the attributes we love and venerate, in what we actually behold. In prosecuting this subject, such a view has constantly forced itself on my mind, and I have felt, that, while the operations I described have displayed much of the Divine power, and wisdom, and goodness, I was, after all, only taking an ignorant and superficial survey of a subject of infinite extent,-only looking at the elegant external proportions, and the outward grace of a building, which within was full of a fitness and a grandeur, that, in this mortal state, with my limited faculties and imperfect knowledge, I was not permitted either to approach or to conceive. How delightful is the assurance, that the time will come, when, if we belong to that blessed company who inherit the promises of the Gospel, we shall no longer see as "through a glass darkly." "When that

which is perfect is come," and we see "face to face," the further discoveries, which our enlarged faculties shall be

permitted to make, will, as we may well believe, form no mean part of the happiness which Heaven has in store for us.

FOURTH WEEK-THURSDAY.

INSTINCTS CONNECTED WITH THE REPRODUCTION OF ANIMALS.

HOWEVER curious and instructive the subject of reproduction may be, in relation to its physiological laws and conditions, it is certainly not less so as regards the instinctive propensities and habits, by which these are brought into operation and rendered effectual for the accomplishment of the great object the Creator had obviously in view; and there are few things more wonderful, or more strikingly indicative of wise and harmonious design, than the adaptation of the animal instincts to the physical circumstances of the parent, the embryo, and the offspring.

The single fact, that, immediately after the wintry blast, which desolated Nature, has ceased, and as soon as Spring has begun to scatter a profusion of food over the face of the earth, and to cheer and nourish all things with her balmy breath, the lower animals should choose their mates, and those remarkable instincts should commence their influence, which are to repair the waste occasioned by the law of universal decay, and constantly to replenish the world with living beings, is, in all its circumstances, a phenomenon which, on the most superficial glance, clearly indicates the plan of an Intelligent Creator.

When, from this general view, we turn to the operation of these instincts in the various races of the animated world, we find, with admiration and delight, the same uniformity mingled with diversity, which distinguishes the operations of the Creator in other departments of His works, the same adjustment of causes to ends, of instincts to forms, of propensities to propensities, and of one condition to all the rest.

I shall at present take a rapid view of these reproduc

tive instincts, as they appear in the various tribes of animals, with the intention of afterwards filling up the sketch by such details as may serve more fully to illustrate the Divine perfections, exhibited in the means made use of for the preservation of animal life through successive generations.

To begin with the insect world; these have all their seasons for fulfilling the great law of Nature, varying according to their peculiar functions and destinies, numerous as these are, to which the organization of each is most admirably adapted. It is exceedingly remarkable, as we shall presently see, to observe how each is directed to deposit its eggs, where its young, when disclosed, may find their appropriate nutriment. Various circumstances seem to point to the scent,* as the sense by which they are directed to the proper station for their eggs. But whatever there may be in this, the inward propensity is not the less admirable, which conducts by far the most numerous classes of insects, and more especially the whole tribes of the Lepidoptera, to seek for a place of deposit for their precious charge, where their larvæ, when developed, may find a species of food suitable for the offspring, but never once used by the parents.

Of vertebrated animals, the lowest classes are coldblooded, including reptiles and fishes. These seem to have little of that instinctive attention to the welfare of their offspring, which belongs to many of the insect tribes, and is not less remarkably exhibited by numerous families of the warm-blooded animals. They, however, are invariably instructed by the Creator, to select a proper situation for their eggs or spawn, where they may be hatched either by artificial heat, or that of the sun. Snakes, and

other Ophidians, bury their eggs in sand, and not seldom even in heaps of fermenting manure, while the venomous species of serpents are hatched within the parent. The lizard tribes, from the crocodile downwards, lay their eggs in some well-selected spot, and then leave them to the

*The flesh-fly, deceived by the smell, frequently lays her eggs on the carrion plant, mistaking it for a piece of decaying flesh, which it greatly resembles in its disagreeable odor.