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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 Medusa, 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,

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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.

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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.

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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 might adopt with advantage some of the

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plans which the experienced proprietor of the Surrey Gardens finds so successful in preserving the health of the more delicate animals. His monkeys, for example, instead of being confined by twos and threes in close cages, are preserved in a large space, well ventilated and heated, and defended by a glass frame; and here they can disport and exercise themselves throughout the whole winter.

At the Scientific Meeting, held on the 12th of February, some interesting communications were read, including a letter from M. Geoffroy St. Hilaire, referring to some observations lately published by Mr. Owen on the Ornithorhynchus paradoxus of New South Wales; from Capt. Hallam, with an account of the Mango Fish; and Mr. Martin's notes on the dissection of a Lemur.

Notice of a Motion on the subject of closing the Gardens on Sunday during the hours of Divine Service has been given; and it was stated that sales of many of the animals. now at the Farm at Kingston, and duplicates of those in the Gardens, are about to take place during the spring.

ZOOLOGIST'S CALENDAR FOR MARCH.

The animals which we mentioned in our Calendar for January, as being in a state of torpidity, are now beginning to show some symptoms of existence, and to re-appear after their winter's repose. To these we may add the Tortoise (Testudo græca), and the Toad (Bufo vulgaris), which also make their appearance in the course of the present month. To such of our readers as are anglers it will almost be superfluous to remark that now trout begin to rise.

The Crow (Corvus corone) begins to build : several kinds of Birds lay their eggs and sit in the course of this month. Amongst others, we may enumerate the Blackbird (Turdus Merula), the Turkey (Meleagris Gallopavo), and the Raven (Corvus Corax). It is only occasionally, however, that this occurs, as it is more frequently during the next month that these birds lay their eggs.