This mode of generation, however, enables us to comprehend the miraculous fecundity of these beings. The process defies calculation, if we wished to be precise. We may, however, arrive at a proximate estimate of the number which may be derived from a single individual by this process of fission. It has been found that at the end of a month two Stylonichiæ had a progeny of more than one million and forty-eight thousand individuals, and that in a lapse of forty-two days a single Paramecium had produced more than one million three hundred and sixty-four thousand forms like itself.

Life is spread over Nature in such abundance that the smallest infusoria has its parasite a little smaller; these in their turn serving as "a dwelling and pasture ground," to use Humboldt's words, for still smaller animalcules, as represented in Fig. 29—a being parasites in various stages; b, the larger animalcule on which they have established themselves.

The prodigious number to which the calculation would reach, if we were to add the other modes of propagation, viz., by germs and by budding, we dare not mention: it would only be necessary to place a single germ in a favourable condition for its development, in order to produce myriads of these microscopic animalcules in a very few days.

We have seen three modes of reproduction in the Infusoria; it is possible that a fourth mode exists, to which its partisans give the name of spontaneous generation. According to their views, an infusoria can be produced without egg-germ or pre-existent parent. It would be sufficient to expose organic matter, animal or vegetable, to the action of the air and water at a suitable temperature, in order to see this matter organize itself, and form itself into living infusorial animals.

Such is the general enumeration of the question of spontaneous or heterogeneous generation, on which so much has been written in the last ten years. The great expounders of the doctrine have been the two French naturalists, MM. Pouchet and Joly. Their views have, however, made little progress; they have, on the contrary, met with vigorous opposition from the generality of French naturalists, and from most of the members of the Académie des Sciences of Paris, who have raised their voices against a doctrine which is contrary to the ordinary course of nature. In short, the direct observations made upon the theory of "primitive generation" are as yet wanting in necessary exactness; those observers who profess to have witnessed the sudden origin of the minutest of the infusoria from elementary substances have in all probability overlooked the organic structure of these elementary bodies. The wonderful changes of form undergone by many infusoria have their limits, and the laws governing them have still to be defined. With the poet we may say:

"Grammatici certant et adhuc sub judice lis est."

Many of the Infusoria are subject to metamorphoses, and it has already been ascertained that certain species which have been considered as distinct are only transition forms of the same species depending on age.

We know that it is common for insects to enclose themselves in protecting envelopes, and to remain for whole months shut up in this their retreat, to all appearance dead. Similar facts have been observed in the Infusoria. We have even seen some of these beings surrounding strange bodies as if in a mass of jelly, forming a sort of living envelope around them.

The average duration of life with them is only a few hours; but certain species present, in relation to the duration of life, phenomena which are only imperfectly known, but which never fail to excite the surprise and admiration of the naturalist. By drying certain infusoria with care, it is possible to suspend and indefinitely prolong its life. Thus dried, and covered with a powder, which shelters it from every breath of wind, it may be carried to any given distance, through any indefinite period of time—abandoned on some ledge of rock, on a housetop, in the cleft of a wall, or under the capital of a column; but let a drop of water approach it, and the dormant being awakes immediately—the microscopic Lazarus springs again into existence: feeds and multiplies as before: and its life, suspended possibly for years, resumes its interrupted course!

Into what a world of reflection does not a revelation of this mysterious property of a living creature plunge us!

The physiologist Müller has noted another peculiarity in infusorial life. These animalcules can lose a part of their bodies without being destroyed; the dead part disappears, and the individual, diminished by one-half, or reduced to a fourth of its former size, continues to live as if nothing had happened. Müller has observed a kalpode (Kolpoda meleagris) thus melt before his eyes until scarcely a sixteenth part of its body remained. After its loss, this sixteenth part of an animal continued to swim about without troubling itself as to its diminished proportions. "The infusoria," says Frédol, in "La Monde de la Mer," "present yet another kind of decomposition. If we approach the drop of water in which it swims with the barb of a feather dipped in ammonia, the animalcule is arrested in its movement, but its cils continue to move rapidly. All at once, upon some point of its circumference, a notch is formed, which increases bit by bit until the whole animal is dissolved. If a drop of pure water is added, the decomposition is suddenly stopped, and what remains of the animalcule recommences its swimming movements." (Dujardin.)

We may divide the Infusoria into two orders—the Ciliate Infusoria, namely, those provided with vibratile cilia, and the Flagelliferous Infusoria, those, namely, which have arms or branches. The greater part of Infusoria belong to the first order, which comprehends many families; our space limits us to the mention here of a few typical forms only in each group, selecting those which appear the most interesting, from their size, structure, rarity, or abundance.

Flagelliferous Infusoria.

The family of Vibrionidæ, so named from their darting or quivering motion, includes the eel-like microscopic animalcules which occur in stale paste, vinegar, &c., with some others, which are parasitic on living vegetables, such as Vibrio tritici, which infest the grains of wheat, producing the destructive disease called corn-cockle or purples. They are filiform animals, extremely slender, without appreciable organization, internal stomach, or apparent organs of locomotion. They are the first animalcules which show themselves in any infusion of organic matter. By using microscopes of the highest magnifying power, traces of very thin, short lines can be perceived, either straight or sinuous, the thickest of them not exceeding the thousandth part of the fraction of an inch. They are contractile, and propagated by spontaneous division, or fission. Among them some resemble right lines, more or less distinctly articulated, and endowed with a very slow movement; these are Bacteridæ. Others are flexuous and undulating, and more or less lively; these are true Vibrions. Others have the body fashioned in the form of a corkscrew, turning unceasingly upon themselves with great rapidity; these are the Spirillidæ, having an oblong fusiform or filiform body, which undulates or turns spirally upon itself.

The Bacterium termo (Fig. 30) is the smallest of the Infusoria. It is found, at the end of a short time, in all vegetable or animal infusions exposed to the air. It shows itself in infinite numbers, forming swarms of animalcules, which disappear as other species multiply in the liquid, to which animals it serves for nourishment. When the infusion becomes too fœtid for these new species to live in it, in consequence of fermentation or putrefaction, the Bacterium termo reappears. This species was one of the first observed; Leuwenhoek found it in the white matter in the teeth and gums, which is called teeth tartar. It is also found in the fluids of various animals which have been affected by disease.

The Wand-like Vibrion (Fig. 31) has the body transparent, filiform, with long articulations, often appearing as if broken at each connection. It moves very slowly in the water. Leuwenhoek observed this second species joined to the first in the teeth tartar, and also in a great number of organic infusions. "There is no microscopic object," says Dujardin, "which excites the admiration of the observer more vividly than the twisting spirillum" (Fig. 32). He is struck with surprise when he first contemplates this little creature, which, under the greatest magnifying power, only presents the appearance of a thin black line, fashioned like a corkscrew, which every instant turns upon itself with marvellous velocity, such as the eye can scarcely follow, or the mind divine the cause which produces this startling phenomenon.

The Monads are other infusorial animalcules which make an early appearance in vegetable infusions. They constitute a family that are destitute of any covering. The substance of their bodies can swallow itself, or draw itself out more or less; many of the whip-like filaments serve as organs of locomotion. They are sometimes provided with lateral appendages disposed as a kind of tail. Their organization is extremely simple; their whip-like filaments are so fine as to be scarcely perceptible, their length being sometimes double and even quadruple the length of the animal itself.

The Lentille Monad (Fig. 33) is a species which is frequently met with in vegetable and animal infusions. The older microscopists had it indicated under the form of a globule, moving in a slow and vacillating manner. The globule is formed of a homogeneous transparent substance, swollen into tubercles on its surface, and throws out obliquely a whip-like filament, three, four, or even five times the length of the body of the Monad.

The Cercomonad of Davaine was discovered by this gentleman in the still warm ejections of cholera patients. Its body is pyriform, having, in front, a vibratile filament, very long, very flexible, and easily agitated. Behind the body there is a thicker straight filament attaching itself sometimes to neighbouring corpuscles, round which, in this case, the Cercomonad oscillates like the ball of a pendulum round its stem.

The Volvocineæ are inhabitants of fresh limpid water full of confervæ and other aquatic plants. The Volvocineæ are, according to Dujardin, animalcules of a green or yellowish brown colour, regularly disseminated in the thickness and near the surface of a gelatinous and transparent globe, which would become hollow and be filled with water in its perfect state. In this state, from five to eight smaller globules, with the same organization, appear destined to undergo the same changes when they are released by the rupture of the globule. These animalcules are each furnished with one or two flagelliform filaments, which, by their agitation, determine the movement by rotation of the mass.

A very remarkable phenomenon is recorded in the Transactions of the Microscopic Society, namely, the conversion of the contents of an ordinary vegetable cell into a free moving mass of Protoplasm, bearing a strong resemblance to the animal Amœbæ (Fig. 20). This, it is affirmed by Dr. Hicks, takes place in Volvox, under circumstances which suggest a vegetable transformation. But Dr. Carpenter does not consider that this involves any real confusion in the boundaries of Animal and Vegetable Life.

The Revolving Volvox, V. globator (Figs. 34 and 35), is found in great abundance, during summer, in tanks and ponds of stagnant water. It consists of green or brownish-yellow globules about the eighth part of an inch, formed of animalcules scattered round a gelatinous and diaphanous spherical membrane, each furnished with a flagelliform filament and with a reddish interior point, which Ehrenberg took for an eye. Leuwenhoek first observed this Volvox in marshy waters. This eminent naturalist has left a very interesting account of his observations on these microscopic inhabitants of the waters, displaying an amount of patience and address which cannot be too much admired; his observations were made with a simple lens, which he constructed himself. In one hand he held his instrument, which was very coarse if we compare it to the more perfect and infinitely more powerful instruments now in use; whilst, in the other hand, he carried to his eye the glass tube full of water which contained the object under observation. "The microscopes of Leuwenhoek," says Dujardin, "were the very smallest bi-convex lenses, mounted in a silver frame. He made a collection of twenty-six, which he bequeathed to the Royal Society of London. These instruments, subject to all the inconveniences of a maximum of spherical aberration and a total want of stability, were only fit for use in the hands of Leuwenhoek himself, who had acquired, in his labour of twenty years, habits of observation which compensated, in great part, for the want of perfection in his instruments."

The Eugleniæ are infusoria usually coloured green or red. Their form is very variable. They are oblong or fusiform in shape, swelling at the middle during action, and contracted or bowl-shaped in repose, or after death. They are furnished with the usual whip-shaped filament, which issues from an opening in front, and from one or many reddish points irregularly placed anteriorly.

Euglenia viridis (Fig. 36) is the most common species, and, perhaps, the most widely diffused of all the Infusoria. It is this animalcule which habitually covers stagnant pools with its floating surface of green, and which forms, on the surface of marshy waters, the shining pellicle so strongly coloured, which, collected upon paper, so long preserves its brilliant tint.

The Euglenia sanguinea, at first green, becomes subsequently of a blood colour. It has often been met with by microscopists. Ehrenberg, who first described it, attributes to its great abundance the red colour of some stagnant waters. Its presence explains the pretended miracle of water changing into blood, which was frequently invoked by the Egyptian priests.

Ciliate Infusoria.

Let us now take a glance at some of the more remarkable species of Ciliate Infusoria. The bodies of these creatures are all more or less translucent. They have not substance enough, in fact, to reach a state of opacity. Their bodies are more or less globular or ovoid, sometimes fashioned like a shuttle, or curved while growing, sometimes swollen in the middle like an ampulla, or bell-shaped, and flattened into a discoid shape; some slightly resemble a tadpole, a thimble, a shoe, a rose-bud, a flower, even a seed.

The Paramecians have a soft flexible body, usually of oblong form, and more or less depressed. They are provided with a loose reticulated covering, through which issue numerous vibratile cilia, arranged in a regular series. They were known to the older naturalists; and it is in this group that organization is carried to the highest perfection it attains among the Infusoria. The Paramecium possess, besides their reticulated and contractile tegument, cilia disposed in such a manner as to serve at once for locomotion, for prehension, that is, for seizing its food, and as a means of respiration. They are furnished with a mouth, at the bottom of which the whorl excited by the cilia determines, according to Dujardin, the hollowing out of a cavity, formed after the manner of a cul-de-sac, and also the formation of vacuoles with permanent partitions, in which are enclosed the substances which the animalcules have swallowed along with the water.

The Paramecium are propagated by spontaneous division, as already described. They abound, as we have said, in stagnant water, or in pure water which is occupied by aquatic plants, sometimes in such prodigious quantities that they become troublesome. They occur also in flower vases where the water is not frequently renewed.

The species of this genus have an oblong compressed body, with an oblique longitudinal fold, directed towards the mouth, which is lateral. They are sufficiently large to be observed by the common lens, or eye-glass. Paramecium aurelia appears chiefly in vegetable infusions. It is common in ditches and moats with aquatic plants.

Humboldt's assertion is fully verified in the case of the Infusoria under consideration, which is often found with its parasites. These are small creatures, cylindrical in form, and provided with suckers. Swimming vigorously in the water, they devote themselves to chasing the Paramecium. When they have overtaken the fugitive, they throw themselves upon it, and establish themselves there. They soon multiply in the interior of its body, and their starving progeny suck and devour the unfortunate animalcule, which serves them at once for dwelling-house and larder.

Another of the parasites which prey upon the Paramecium, in place of pursuing it, remains perfectly quiet until one of these approach, when it throws itself upon its victim, and is carried along with it. It buries itself in the body of the Paramecium, and, in a short time, multiplies to such a degree, that sometimes fifty of them are found on a single individual. Poor victim!

The Nassula have the body entirely covered with cilia; they are ovoid or oblong in form, contractile, the mouth placed laterally and dentate, or surrounded with a band of horny bristles, the band dilating and contracting according to the size of the prey which it would swallow. It either advances to seize the prey, which the movement of vibratile cilia have failed to draw within the vortex of its mouth, or, as in the case of the Paramecium, it is sometimes obliged to seek for its prey. These curious infusoria live in stagnant waters, feeding on the débris of aquatic plants, from which they draw their chief nourishment as well as their colour.

The Bursarians are animals with an oval or oblong contractile body, provided also with vibratile cilia, especially on the surface, having also a large mouth, surrounded with cilia, forming a sort of microscopic moustache, spirally arranged.

Among the species belonging to this group may be noted the Condylostoma patens (Fig. 39), remarkable for its size and voracity. It sometimes attains the twelfth of an inch, and abounds on every shore from the Mediterranean to the Baltic. Another Bursarian, a species of Plagiostoma, lives between the intestines and the external muscular bed of the earth-worm, Lumbricus terrestris. To the group of Urceolarians belong the Stentors, which are in number the most numerous of the Infusoria; they are, for the most part, visible to the naked eye.

The Stentors are inhabitants of fresh, tranquil water, not subject to agitation, and covered with water plants. They are nearly all coloured green, blackish, or blue; their bodies covered with cilia. They are eminently contractile, and very variable in form. They can attach themselves temporarily, by means of the cils at their posterior extremities, when they assume a trumpet-like form, the bell of which is closed by a convex membrane, the edge being furnished with a row of very strong obliquely-placed cilia, ranged in a spiral, meeting at the mouth, which is placed near this edge. When they swim freely, they alternately resemble a club, a spindle, or a sphere. The Stentor Muelleri is seen in ponds in the neighbourhood of Paris and elsewhere; it has been found even in the basins of the Jardins des Plantes (Fig. 40).

The animals which constitute this genus are fixed in the first part of their existence, but free in the second. So long as they are fixed, they resemble, in their expanding state, a bell or funnel, with the edges reversed and ciliate. When they become free, they lose their crown of cilia, take a cylindrical form, more or less ovoid and elongated, and move themselves by means of a new organ. "There is no animal," says Dujardin, "which excites our admiration in a higher degree than the Vorticellate Infusoria, by their crown of cilia, and by the vortex which it produces; by their ever-varying forms; above all, by their pedicle, which is susceptible of rapid spiral contraction, by drawing the body backward and again extending it. This pedicle is a flat membranous band, thicker upon one of its edges than the other, and containing on the thicker side a continuous channel, occupied, at least in part, by a fleshy substance, analogous to that of the interior of the body. During contraction, this thick edge is shortened more than the thin side, and hence results the precise form of the spiral of the corkscrew."

We cannot conclude our brief history of these curiously-organized beings without recording the doubt which still exists in the minds of our most eminent naturalists, whether some of those we have named are animal or vegetable in their origin. The Desmideæ, long classed among animals, are now generally recognized as plants. The group of Diatomaceæ are still considered doubtful, and the Monads and Volocina are still subjects of discussion, the evidence inclining in favour of those who argue for their vegetable nature. Messrs. Busk, Williamson, and Cohn, have published in the "Microscopical Transactions" minute details of the evolutions of these curiously-organized globules, which seem to prove their vegetable nature. On the other hand, it is difficult to imagine so accurate an observer as Agassiz writing so positively as he does on a doubtful subject. Remarking on a former paper, in which he had shown that the embryo hatched from the egg of a Planaria was a true polygastric animalcule of the genus Paramecium, he adds, that in former writers a link was wanting, viz., tracing the young hatched from the egg of Distoma. "This deficiency," he says, "I can now fill. It is another Infusorium, a genuine Opalina. With such facts before us there is no longer any doubt left respecting the character of all these Polygastria; they are the earliest larvæ condition of worms." Amid these friendly disputes we congratulate ourselves that we have to do with the oceanic creations, both animal and vegetable.

CHAPTER V.

Thus regarded, the Polyps comprehend a great variety of animals, the bodies of which are generally soft or gelatinous substances. The principal and smaller divisions, to the number of more than two, are arranged round an imaginary axis, represented by the central part of the body. These divisions of the body have in their ensemble the appearance of a regular cylinder, of a truncated cone, or of a disk. They are invested with a skin or envelope of calcareous or siliceous corpuscles, and even a portion of the deepest-lying tissues may be invaded by a calcareous deposit, the mass of which belongs sometimes to an individual; sometimes it is common to many, constituting what Dr. Johnston calls the Polypidom, of which Professor Grant says, "there is but one life and one plan of development in the whole mass, and this depends, not on the Polypi, which are but secondary, and often deciduous parts, but on the general fleshy substance of the body;"[5] "the ramifications," says Dr. Johnston, "being disposed in a variety of elegant plant-like forms. The stem and branches are alike in texture: slender, horny, fistular, and almost always jointed at short and regular intervals, the joint being a mere break in the continuity of the sheath, without any character of a proper hinge, and formed by regular periodical interruptions in the growth of the polypidoms. Along the sides of these, or at their extremities, we find the denticles or cup-like cells of the polypi arranged in a determinate order, either sessile or elevated on a stalk." Near the base of each of these there is a partition or diaphragm, on which the body of the polyps rests, with a plain or tubulous perforation in the centre, through which the connection between the individual polyps and the common medullary pulp is retained. Besides the cells, there are found at certain seasons a larger sort of vesicle, readily distinguished from the others by their size, and the irregularity of their distribution, which are destined to contain and maturate the ovules.

With these animals the digestive tube is very simple, and presents only one distinct orifice; the same opening serving at once for receiving the food and the expulsion of the residuum of digestion. This is one of Nature's economies, which it is not for us to dispute: we must record it without further remark.

In nearly all the Polyps the sexes are separate; the generation is sometimes sexual; but these beings multiply also by what the zoologists call gemmation, or buds. They are provided with organs of the senses; nearly all of them have eyes—an immense progress in organization as compared with the animals which have hitherto engaged our attention. Their respiration is effected by the skin—another instance of the economy of Nature. The apparatus of their circulation is indistinct, but they have a nourishing fluid analogous to the blood in vertebrated animals. Vibratile cilia and stinging hairs often cover the entire surface of the Polyps.

These general remarks may appear obscure and insufficient to the larger number of our readers. They are necessarily so; they are generalities upon animals very little known, even to naturalists. We quit this difficult ground, trusting to make the special study of the several types we shall have to describe more interesting. The group of Polyps divide themselves into many classes, namely, the Alcyonidæ, the Zoanthina, the Discophora, and Ctenophora. It will be our task to describe in succession the habits and characters of each of these classes, dwelling on such species as appear to us to offer to the reader most real interest.

CHAPTER VI.

I. THE TUBIPORINÆ

form a group consisting of several species, which live in the bosom of tropical seas, in which the Coral Islands form so prominent a feature. The group is exclusively formed of the curious genus Tubipora.

The Tubipora is a calcareous coral, formed by a combination of distinct, regularly-arranged tubes, connected together at regulated distances by lamellar expansion of the same material. The aggregate formation resulting from this combination of tubes constitutes a rounded mass, which often attains a very considerable size. In Fig. 41 we have a representation of the zoophyte Tubipora musica and its product, which is sometimes designated by the vulgar name of Sea-Organ. In the engraving, 1 is the calcareous product, reduced to half its size; 2, is a portion in its natural size; 3, the tubes magnified, and containing the polyp which occupies the summit of the tube, the whole of which constitutes this curious coral; 4, is the polyp magnified; 5, the head or collection of tentacula of the individual polyp.

Zoologists of the last century confounded all the species of this genera inhabiting the tropical seas, making only one species, to which they gave the name of Tubipora musica. But it is now known that there are many species of Tubiporæ, readily distinguishable in a fresh condition by a difference in the colour of the polyps. The tissue of these singular beings is of an intensely red colour. The disposition of their tubes in the style of organ pipes has always attracted the attention of the curious inquirer into the secrets of Nature.

II. GORGONIADÆ.

Milne Edwards divides this order into three natural groups:—I. The Gorgoniadæ. II. The Isidians. III. The Corallines.

The Gorgonians are composed of two substances: the one external, sometimes gelatinous and fugitive; sometimes, on the contrary, cretaceous, fleshy, and more or less tenacious. Animated with life, this membrane is irritable and encloses the polyp; it becomes friable or arenaceous in drying. The second substance, internal and central, sustains the first, and is called the axis. This axis presents a horny appearance, and was formerly believed to possess chemical characters analogous to the horns and hoofs of some of the vertebrated animals. It has recently been asserted that the tissues of these corals consist essentially of a particular substance which resembles horn, but which is called Corneine. A little carbonate of lime is sometimes found united with this substance, but never in a sufficient quantity to give it a stony consistence. This outer covering developes itself in concentric beds, between the portion of the axis previously formed and the internal surface of the sclerotic covering.

The mode of growth in this axis presents great variations. Sometimes it remains simple and rises like a slender rod, sometimes it has numerous branches. It is arborescent when the branches and their accompaniments take different directions so as to constitute tufts. It is panicled when they arrange themselves on both sides of the stem or principal branches, after the manner of the barbs of a feather. It is flabelliform when the branches rise irregularly under the same plane; reticulated, when branches are so disposed as to be attached to each other by network in place of remaining free.

The Gorgoniadæ are found in every sea, and always at considerable depths. They are larger and more numerous between the Tropics than in cold or even temperate climates. Some of these corals scarcely attain the twelfth of an inch in height, while others rise to the height of several feet.

Formed in the bosom of the ocean, it is only necessary to behold these singular creations in order to admire the brilliant colours which decorate their semi-membranaceous branches. The brilliancy of their robes are singularly diminished, have almost entirely disappeared, indeed, when they make their appearance in the cases of our natural history collections.

The Fan Gorgon, from the Antilles (Fig. 42), is a species which often attains the height of eighteen or twenty inches, and nearly as much in breadth. The network of its interstices with its unequal and serried meshes, resembling fine lace, have led to its designation of Sea Fan. Its colour is yellow or reddish. In Fig. 43 we have the Sea Fan magnified to twice its natural size, showing the curious details of its organization.

The Whorled Gorgon (G. verticellata), which is found in the Mediterranean, is yellowish in colour, and also of elegant form. It is sometimes called the Sea Pen. This species is represented in Fig. 44, while Fig. 45 represents a small branch magnified four times, in order to give an exact idea of its form.

The Gorgons are not known to be useful either in the arts or in medicine. They are ornamental in cabinets, and interesting both as objects of study and of zoological curiosity.

Isidians.

The Isidæ constitute an intermediate group between the Gorgons and Corallines. Their polypidom is arborescent, but its axis is formed of articulations alternately calcareous and horny. The principal genus is that of the Isis, which is met with in the Indian Ocean, on the American coast, and in Oceania. The inhabitants of the Molucca Islands use these animals medicinally as a remedy in certain diseases; but as they use them for the most opposite maladies, it may be doubted if they are really efficacious in any medicinal point of view.

The Isis corolloïdis of Oceania has a coral with numerous slender branches, furnished with cylindrical knots at intervals, contracted towards the middle, finely striated, and rose-coloured. Isis hippuris, represented in Fig. 46, has a singular resemblance to the Common Mare's Tail (Hippuris vulgaris).

Four other species of Isidians are known. The same family includes the genera of Melitæa and Mopsea, which, however, our limits forbid us to describe.

Corallinæ.

The group of Corallines consist of a single genus, Corallium, having a common axis, inarticulate, solid, and calcareous, the typical species of which furnishes matter hard, brilliant, and richly coloured, and much sought after as an object of adornment. This interesting zoophyte and its product require to be described with some detail.

From very early times, the coral has been adopted as an object of ornament. From the highest antiquity, also, efforts were made to ascertain its true origin, and the place assignable to it in the works of Nature. Theophrastus, Dioscorides, and Pliny considered that the coral was a plant. Tournefort, in 1700, reproduced the same idea. Réaumur slightly modified this opinion of the ancients, and declared his opinion that the coral was the stony product of certain marine plants. Science was in this state when a naturalist, who has acquired a great name, the Count de Marsigli, made a discovery which threw quite a new light on the true origin of this natural product. He announced that he had discovered the flowers of the coral. He represented these flowers in his fine work, "La Physique de la Mer," which includes many interesting details respecting this curious product of the ocean. How could it be longer doubted that the coral was a plant, since he had seen its expanded flowers?

No one doubted it, and Réaumur proclaimed everywhere the discovery of the happy Academician.

Unhappily, a discordant note soon mingled in this concert. It even emanated from a pupil of Marsigli!

Jean André de Peyssonnel was born at Marseilles in 1694. He was a student of medicine and natural history at Paris when the Académie des Sciences charged him with the task of studying the coral on the sea-shore. Peyssonnel began his observations in the neighbourhood of Marseilles in 1723. He pursued it on the North African coast, where he had been sent on a mission by the Government. Aided by a long series of observations as exact as they were delicate, Peyssonnel demonstrated that the pretended flowers which the Count de Marsigli thought he had discovered in the coral, were true animals, and showed that the coral was neither plant nor the product of a plant, but a being with life, which he placed in the first "rung" of the zoological ladder. "I put the flower of the coral," says Peyssonnel, "in vases full of sea-water, and I saw that what had been taken for a flower of this pretended plant was, in truth, only an insect, like a little sea-nettle, or polyp. I had the pleasure of seeing removed the claws or feet of the creature, and having put the vase full of water, which contained the coral, in a gentle heat over the fire, all the small insects seemed to expand. The polyp extended his feet, and formed what M. de Marsigli and I had taken for the petals of a flower. The calyx of this pretended flower, in short, was the animal, which advanced and issued out of its cell."

The observations of Peyssonnel were calculated to put aside altogether theories which had lately attracted universal admiration, but they were coldly received by the naturalists, his contemporaries. Réaumur distinguished himself greatly in his opposition to the young innovator. He wrote to Peyssonnel in an ironical tone: "I think (he says) as you do, that no one has hitherto been disposed to regard the coral as the work of insects. We cannot deny that this idea is both new and singular; but the coral, as it appears to me, never could have been constructed by sea-nettles or polyps, if we may judge from the manner in which you make them labour."

What appeared impossible to Réaumur was, however, a fact which Peyssonnel had demonstrated to hundreds by his experiments at Marseilles. Nevertheless, Bernard de Jussieu did not find the reasons he urged strong enough to induce him to abandon the opinions he had formed as to their vegetable origin. Afflicted and disgusted at the indifferent success with which his labours were received, Peyssonnel abandoned his investigations. He even abandoned science and society, and sought an obscure retirement in the Antilles as a naval surgeon, and his manuscripts, which he left in France, have never been printed. These manuscripts, written in 1744, were preserved in the library of the Museum of Natural History at Paris. The title is comprehensive and sufficiently descriptive. It should be added, in order to complete the recital, that Réaumur and Bernard de Jussieu finally recognized the value of the discoveries and the validity of the reasoning of the naturalist of Marseilles. When these illustrious savants became acquainted with the experiments of Trembley upon the fresh-water hydræ; when they had themselves repeated them; when they had made similar observations on the sea anemone and alcyonidæ; when they finally discovered that on other so-called marine plants animalcules were found similar to the hydra, so admirably described by Trembley;—they no longer hesitated to render full justice to the views of their former adversary.

While Peyssonnel still lived forgotten at the Antilles, his scientific labours were crowned with triumph at Paris; but it was a sterile triumph for him. Réaumur gave to the animalcules which construct the coral the name of Polyps, and Coral to the product itself, for such he considered the architectural product of the polyps. In other words, Réaumur introduced into Science the views which he had keenly contested with their author. But from that time the animal nature of the coralline has never been doubted.