CHAPTER VI.

PROVIDENCE OF GOD EVIDENCED IN THE SUPPLY OF FOOD.OBJECTS OF DIGESTION.-HOW ENSURED IN DIFFERENT CLASSES OF ANIMALS.-ORGANS AND FUNCTION OF DIGESTION IN MAN. -HUNGER AND THIRST.-EFFECTS OF EXCESS AND OF DEFICIENCY OF FOOD.-COMPOSITION OF ANIMAL AND VEGETABLE BODIES. NATURE OF DIFFERENT ALIMENTARY SUBSTANCES.PROUT'S AND LIEBIG'S ARRANGEMENT.-DIGESTIBILITY OF DIFFERENT ARTICLES.-PHILOSOPHY OF COOKERY.-CLASSIFICATION OF ANIMAL AND VEGETABLE ALIMENTS. DRINKS. TEMPERANCE.

WITH a consciousness of the necessity of physical sustenance, we pray to Heaven for a continued supply of "our daily bread," and on sitting down to our periodical repast, we feel, it is to be hoped, emotions of gratitude towards the bounteous Giver. Few individuals, however, are sufficiently impressed with the means by which the Creator satisfies the cravings of the countless tribes of animated beings which teem in the air, the waters, or on the surface of our earth. If we reflect for one moment upon the almost endless manifestations of life, the thousand million human beings scattered over the globe, the amazing variety of quadrupeds, frequently of complex structure and gigantic dimensions, the tribes of insects, reptiles and birds in the tropics, utterly beyond calculation-not to omit the different classes of creatures varying in form, size, and intricacy of organization which people the mighty

deep,-whose surface, at night, often glows with minute animalcules, clothed in phosphorescent light; if we reflect upon all this exuberance of life, the Divine bounty will present itself to our minds in its full breadth and grandeur, and we shall feel somewhat of the spirit in which the Psalmist celebrates the wonderful providence of God. "O Lord, how manifold are thy works! in wisdom hast thou made them all: the earth is full of thy riches. So is this great and wide sea, wherein are things creeping innumerable, both small and great beasts. There go the ships; there is that leviathan, whom thou hast made to play therein. These wait all upon thee, that thou mayest give them their meat in due season. thou givest them they gather: thou openest thine hand, they are filled with good. Thou hidest thy face, they are troubled: thou takest away their breath, they die, and return to their dust. Thou sendest forth thy spirit, they are created; and thou renewest the face of the earth. The glory of the Lord shall endure for ever: the Lord shall rejoice in his works.”*

That

While, on the one hand, we recognize the power of the Creator in the infinite fertility of resources by which the supply of food is varied with the peculiar condition of each tribe of animals, we are, on the other hand, attracted by His love for his creatures, evidenced in the association of the keenest enjoyment with the necessary relief of their wants. It has been argued that life might have been sustained in some other way than by food; or, admitting the necessity of this, that the mere pang of hunger

Psalm civ. v. 24-31.

would have impelled animals to procure it.* The addition of a sense of pleasure is altogether_a gratuitous exercise of Divine benevolence. In most animals, the act of taking food constitutes the principal enjoyment of their existence; in man, the enjoyment, though undeniable, is, or should be, subservient to higher gratifications. For animals, Providence has prepared an ever-spread table: man rests under the sentence of labour, "in the sweat of thy face shalt thou eat bread," but even this may be productive of good in evolving the resources of his nature, and promoting his intellectual develop

ment.

Not less marvellous than the profusion with which food is supplied to all creatures, is the way in which each is furnished, by the modification of one simple principle of construction, with the apparatus necessary for the reception of the aliment, and its preparation for the purposes of life. All organic beings are provided with a cavity or cavities in which the food is retained, while, by the action of certain secretions, it is converted into matter similar in composition to that of the body of which it is to form a part. This, in a few words, constitutes the object of digestion. Plants, though stationary, have roots, which ramify under ground, and take up nourishment from a comparatively large extent of surface. This nourishment passes along vessels up the stem to the leaves. In these it loses much of its watery part by evaporation; carbonic acid, partly derived from the sap, partly taken in from the atmosphere, becomes decomposed; the carbon is *Paley's Natural Theology.

retained and fixed, and, in conjunction with other matters, contributes to the proper secretions and tissues of the plants. In consequence of the food of plants being always fluid, no special cavity is required; the delicate vessels and cells constitute the digestive apparatus. In the lowest class of animals, however, there is a distinct cavity for the reception and digestion of alimentary matter. In some, this is a mere tube passing directly through the body of the animal; in others, it consists of a sac, sometimes open above and below, at others having but one opening, through which the remains of the food, after digestion, are expelled. Many of the animalcules, known scientifically as polypes, are perfectly transparent, and by placing them under the microscope in their living state, we may study their structure and vital processes. There is something very provocative of curiosity in all that pertains to these little creatures, something humbling to the pride of man in the contemplation of these microscopic phases of existence. I am acquainted with a scientific enthusiast, who owns to having devoted all his leisure hours, for several weeks, to the observation of one little family party of animalcules, and I can well believe that he was repaid for the time thus spent. One of the polypes, the Hydra, seen under a magnifying glass, or almost with the naked eye, is found to have a simple digestive cavity, the mouth of which is surrounded by long tentacles. These, when the creature is watching for prey, remain expanded, and as soon as any small animal touches one of them, it is arrested and conveyed into the stomach. One peculiarity of the hydra is, that it will per

form its functions just as well when turned inside out. By feeding infusorial animalcules with coloured matters, Ehrenberg was enabled to show that they possessed rather a complex digestive apparatus, some having a distinct separation of stomach from intestine, others having a long digestive tube, with little sacs opening into it. These animalcules are furnished with ciliæ or hair-like appendages, in constant action, and varying in their arrangement; some, when in movement, having the appearance of a revolvingwheel. In some of the acalephæ, or sea-nettle tribe, absorbent vessels pass along the tentacles to the stomach, which is separated by partitions into different cavities, out of which vessels pass, and ramify over the system.

Ascending higher in the scale, we find, in the star-fishes and sea-urchins, a more highly-developed structure; in the latter there is a very complex mouth, and a long gullet, followed by a stomach which ends in a convoluted intestine. In the leech, belonging to class Annelida, the stomach, divided into numerous chambers, extends through two-thirds of the body, and ends in a small intestine. Insects present much variety in the digestive organs; some have mouths adapted for sucking-others, for bruising; in these creatures we also meet with organs for the secretion of saliva and bile. In the Crustaceans, as the lobster and crab, the apparatus for digestion is peculiar. The mouth is furnished with several pairs of jaws; the gullet is short and leads into the stomach. This is attached to the shelly coat of the animal, and consists of five half-bony pieces, to the inside of which five teeth are attached;