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ACCOUNT OF THE RED-THROATED MUMMING-BIRD.

91

sion of the powder is sometimes sufficient to stun them and bring them to the ground. It scarcely need be observed, that even the

very
finest shot should not be used in the

pursuit of these small birds, for a single grain would shatter them and leave only a wreck of their beauties. These plans are but ill adapted to their object, as water injures the feathers of the bird, and sand makes it fall to the ground. I have therefore had recourse to two other methods; I have employed with success the net called spider's web, with which I surrounded the shrubs at the distance of a foot or two. The bird cleaves the air with such rapidity that it has not time to perceive the net, and is thus easily caught. I have also made use of green gauze in the shape of a butterfly net; but this method requires much patience, and can only be employed on plants and small shrubs. The person must be carefully concealed; for although the bird will approach very near, it is not the less distrustful; and if any strange object should excite his suspicion, he quits the flower, rises about a foot above the plant, remains there perfectly stationary, examines the object which disturbs him, and when he has ascertained that his fear is well founded, he utters a cry and disappears. To have any degree of success in this pursuit, a little niche must be constructed as low as possible with plants and surrounding shrubs, from which the bird may be covered with the net, in the same way that a butterfly is caught.

"Lastly, having observed that these birds often perched upon the dead branches of shrubs-and wishing to behold in the sun and on the living animal, all the beauty of a plumage resplendent with a thousand hues, the brilliancy of which is tarnished by the hand of death, I inserted some small sticks into the flowers, upon which they perched. I had thus for a minute the pleasure of seeing them dart their tongue into the nectarbearing cup, to draw from it a liquor suited to the delicacy of

“This bird places its nest on trees and shrubs; the inside consists of the brown down of the sumac, and the outside is covered with lichens. The one which I have preserved was on a small branch of the red cedar. The male brings the materials, and the female arranges them; two eggs are laid of a size proportioned to that of the bird, and each parent sits alternately.

their organs.

OBSERVATIONS ON SOME MOLLUSCA AND ZOOPHYTES, RE

GARDED AS THE CAUSES OF THE PHOSPHORESCENCE OF

THE SEA.

[Translated from “Freycinet's Voyage autour du Monde.") Ir is in places where the phænomena which assist in their production are constantly renewed, where floods of light and heat penetrate and warm the water, where electricity seems profasely diffused through every substance,-that myriads of animalculæ are, as it were, spontaneously produced. When a perfect calm succeeds to the light breezes which agitate the surface of the sea, it seems as if a magic wand animated the bosom of the waters, and that their constituent principles had assembled and joined together to produce life.

We have often contemplated this spectacle; it broke the monotony of calms, and diminished the ennui of long voyages. But no one is ignorant, that it is necessary to be initiated in the study of the secrets of Nature in order to appreciate her wonders; for these seas, so full of life to the observer, are inanimate and devoid of interest to the generality of men, who only regard the more striking objects.

It is chiefly in straits near the land, and in rather shallow places, that the animalculæ are produced in the greatest, numbers. In the Molluccas, for instance, one need only draw up a little water in a bucket in order to procure several varieties of them. Some are long and cylindrical; others circular and flattened. The greatest number are of a round form; these swim and twirl about with much activity, while those seem to consist simply of an immovable gelatinous mass. Sometimes the sea was covered with fibres, with minute filaments, or rather with a kind of dust apparently inanimate, but probably an organized body. It is difficult to form a conception of this productiveness; it equals if it does not exceed that which is going on upon earth.

Phosphorescenceis a phænomenon which, although attached to many different animals, belongs peculiarly to the marine mollusca:-about this, much has been written, and it still leaves a vast field for conjecture; since, as regards the manner in which it is effected, every thing remains to be discovered.

Truly we may say, that we have observed this singular spectacle under all meridians, since we have passed under all; we have even beheld results, which no one has mentioned; and yet we must confess that we are not more advanced in a knowledge of the principle which produces phosphorescence than when we began to examine it ten years ago. Therefore, without aspiring to the honour of starting an hypo

OBSERVATIONS ON SOME MOLLUSCA AND ZOOPHYTES.

93

thesis, we shall content ourselves with adding to the facts already known some simple remarks, by means of which more skilful observers may perhaps develop the cause of the surprising power which those animals possess, which we are now considering.

We can no longer be in doubt as to the general causes of the luminosity of the sea. Naturalists have shown that it is produced by animalculæ which multiply in its waters; that it belongs neither to the liquid, nor to electricity, still less to putrefaction; although in that state some mollusca, such as the Salpæ and Calmars, are susceptible of emitting some light, although always of short duration. An active phosphorescence is essentially connected with life ; for animalculæ and mollusca whose vital powers are weakened emit scarcely any light, and that is extinguished when they cease to exist. This luminosity is occasionally an inherent property of the substance of some Medusæ, Salpæ, Beroes, &c., and these animals are not able to strengthen or to weaken it. Others, on the contrary, strange to say! enjoy this power, and can so modify the light, that they spontaneously increase, diminish, or extinguish it altogether, as we shall hereafter mention.

Calm weather, heat, and a superabundance of electricity in the atmosphere increase the intensity of the phosphorescence. Night renders it more apparent, and agitation develops it. All who have sailed between the tropics near to land, and in tolerably shallow water, know what a brilliant train of light the vessel leaves behind her. This beautiful light has exercised the pen of more than one traveller; and each, in describing it according to the impression which it produced upon him, has but too often embellished it still more by an exaggerated description. However it may be, the development of phosphorescence by agitation is a truly wonderful circumstance. When at rest, the waves do not make apparent any other light than that of some large mollusca ; but when they are agitated, every living molecule becomes luminous. And if at the same time the active dolphins play around the ship, they seem to resemble serpents of artificial fire under the water. But when they respire the air with noise, the illusion increases, and we seem to behold and hear the firing of a gun.

No doubt the viscidity of the sea may be referred to this incalculable quantity of animalculæ. The greater number, which are invisible from their transparency, by the aid of phosphorescence become luminous points, which attach themselves to anything that is plunged into the water. Hence probably has arisen the idea that many living fishes were luminous:-it may be so; we do not deny it : yet we must consider them rare,

94

QBSERVATIONS ON SOME MOLLUSCA AND ZOOPHYTES.

as we have never seen them. Fishes may be distinctly seen swimming about when the sea is luminous; and it even seems that they contribute to give it that appearance; but if examined when at rest, it is easy to convince oneself that the power of emitting light is not inherent in them; and that the effect produced by them in this case is the same that may be obtained by agitating any inanimate substance in the sea.'

Our authors then proceed to detail some experiments relative to these phosphorescent phænomena, the results of which may be thus stated.

Diluted sulphuric acid, gently added to sea-water, containing the phosphorescent animalculæ, excited a sudden brilliancy, arising from distinct globules of light, which gradually faded into darkness. A fresh dose of the acid caused a re-appearance of the light: but a third repetition of the experiment produced no effect; the animalculæ were destroyed, and the phosphorescence could not by any means be reproduced. When undiluted sulphuric acid was added to the water, the animalculæ suddenly perished, emitting a slight luminosity. Vinegar and muriatic acid produced the same effect,--the latter especially with much greater force.

“What is the true cause of this phosphorescence? Which is the organ that in the more simple mollusca, as well as the more complicated, serves to impress upon our view such effects? These are questions that, perhaps, will never be answered with certainty. We shall confine ourselves to making a single remark on this subject, which is, that in studying these animals, and handling great numbers of them, our sense of smell has always experienced the same sensation as that produced by a great quantity of electricity collected in the plate of an electrical machine.

“ The observation with which we shall conclude this chapter, is the most remarkable fact of this kind which we have

yet beheld.

“ Having anchored under the small island of Rawak, situated exactly under the Equator, we one evening saw lines of a dazzling whiteness on the water. Crossing them in our canoe, we wished to take up some portion, but we found nothing but water, whose light disappeared in our hands. Soon afterwards, during the night, and while the sea was calm, we saw several of these white steady lines near the ship. Upon examination we discovered that they were caused by some very

small zoophytes; and that these possessed a principle of phosphorescence so subtle, and so capable of expansion, that when they swam swiftly, and in a zigzag direction, they left glittering trains on the sea about an inch wide, which

THE ZOOLOGICAL GARDENS.

95

afterwards increased to two or three inches by the agitation of the waves. Their length was sometimes several fathoms. Generators of this fluid, these animals emit it at pleasure. A luminous point is observed to spring up suddenly on their body, and then to increase rapidly. A bottle, which we laid on the surface of the sea, received two of these animalculæ, which immediately rendered all the water luminous. By degrees this light diminished, and at last disappeared. It was in vain that we endeavoured to perceive the animal with the microscope, or by means of a candle (an easy way of distinguishing transparent mollusca in water); everything had disappeared. We can only say that, by the light which these animals shed, we could perceive that they were extremely minute.

“We have often reflected on the wonderful faculty with which these microscopic zoophytes are endowed; and we have always found it inexplicable, unless we suppose, in order to give a reason for so extraordinary a fact, that they conceal within themselves some principle of phosphorescence, which they emit at pleasure; and that this principle becomes visible only when combined with the water of the sea.

“We only mention a few facts, it is true, but we may venture to assert that they were as well observed as we could do it in our double capacities of physicians and naturalists, and while we were rapidly traversing immense distances.”—Zoologie, ii. p. 402, par MM. Quoy et Gaimard, Médecins de l'Expedition.

THE ZOOLOGICAL GARDENS.

As no addition of any consequence has been made to the Menagerie in the Regent's Park, we have little to add to our last report. The alterations in the grounds we before alluded to are in a state of considerable forwardness, and will form a great improvement both as regards appearance and utility. Although the absence of verdure, of flowers, and of the

gay company which render these gardens so delightful in summer, now conduces to render them less attractive to the general visitor; yet, to the Zoologist, they are perhaps, on that account, more useful, as the animals can be studied with fewer interruptions. We regret to state that the fine old male lion, which has been some time in a declining state, is dead. Some of the monkeys have also been lost, exhausted by the variable and inclement season. We cannot help thinking this Institution right adopt with advantage some of the

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