floor through which it can pass below, than it returns to its companions, and, by means of certain motions of its antennæ, makes some of them comprehend what route they are to pursue to find it; sometimes even accompanying them to the spot; these, in their turn, become the guides of others, till all know which way to direct their steps."

According to Huber, this intercourse is partly maintained by striking the head against the corselet, and by the contact of the mandibles, but chiefly by means of the antennæ. These organs are, no doubt, possessed of a very delicate sensibility, and are not only the seat of the senses of hearing and touch, but may have other capacities of perception of a nature unknown to us. They appear to be closely connected with the instinct of the animal, and to be the medium through which chiefly it receives impressions from without. Ants frequently use them on the field of battle to intimate approaching danger, and to recognize those of their own party when mingled with the enemy. In the internal economy of their dwellings, they are employed to give notice, to those who have the care of the larvæ, of the presence of the sun, exposure to which is so necessary to their development; in their excursions and emigrations, to indicate their route; and in all their various enterprises, to give information as to the time of departure, the order of march, &c. Ants lay up no store of provisions, but depend upon daily supplies; those laborers, therefore, that remain at home, rely upon parties foraging abroad for their regular sustenance. Sometimes this is in the form of small insects or other substances which are brought into the nest. But when the articles of food found are too bulky to be directly conveyed there, the ants fill themselves with their juices, and, on their return, disgorge them for the benefit of those whose labors prevent them from going abroad. The hungry animal begins by striking with both its antennæ, very rapidly, the antennæ of the one from whom it waits its supply. It then draws closer, with its mouth open, and its tongue extended to receive the fluid which may be observed to pass from one to the other. During this operation, the recipient does not cease to caress its benefactor with its antennæ and with its fore feet.

The nature of the information conveyed on these different occasions cannot even be imagined. The communication is not made by any visible gestures, but simply by the contact of the parts. This, indeed, is rendered necessary by the fact that such communication is often required in the total darkness of the interior of the hill. Hence, too, it happens that an ant can only be understood by a single one of its companions at the same time, but the information it conveys passes from one to the others with extreme rapidity.

The means by which bees communicate with each other, and the instrumentality by which information upon important points of their internal arrangements is communicated with inconceivable rapidity to all parts of the hive, are probably of the same general character.

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In one of the lakes in Ceylon, it is the belief of the fishermen who frequent its waters, that musical sounds are heard to proceed from a certain spot, resembling the faint sweet notes of the Eolian harp. Sir Emerson Tennent satisfied himself by a visit to the place that this was actually the fact. They came up from the water like the gentle thrills of a musical chord, or the faint vibrations of a wineglass when its rim is rubbed by a wet finger. It was not one sustained note, but a multitude of tiny sounds, each clear and distinct in itself; the sweetest treble mingling with the lowest bass. On applying the ear to the woodwork of the boat, the vibration was greatly increased by conduction." The last-mentioned fact seems to imply that the sounds were actually produced in the water, and not in the air. Similar sounds have been heard at other places, both in the old and new continents. They have been attributed, with great appearance of probability, to some of the testaceous Mollusca. Their object, we are not sufficiently acquainted with the habits of these animals even to conjecture. That they are totally useless we have no right to assert.

Where sounds proceed from any animal by an arrangement of organs which has their production for its specific object, as in some of the cases above mentioned, it is fair to infer that they are intended to be heard in order to some definite purpose, and consequently to be heard by other animals of the same species.

So that an organ for the production of sound almost necessarily implies in the same animal an organ by which that sound is heard, or at least perceived and appreciated. This is not true of those cases in which the sound is the mere mechanical result of the action of organs in the performance of an ordinary function. Thus the buzz of the common house-fly is a necessary result of the rapid beating of the air by its wings, and does not imply the sense of hearing, though it may coexist with it; but the sounds of the katydid, of the cricket, and those of the bee, as emitted for an obvious purpose, do imply the existence of such

a sense.

It is not improbable that the power of appreciating sounds, either by a distinct organ for this purpose, or else by some organ which has also another function, as the antennæ in insects, is more widely diffused among the lower animals than we are accustomed to imagine. The more minutely researches are carried among such animals, the more perfect and varied is their organization found to be; and it would not be surprising if light and sound were found to be as generally perceived, in some degree at least, as taste and odor.

Some of the prevision which insects evidently possess of changes of weather may be due, in part at least, to an exquisite sense of hearing, that receives impression from the motion of agents which usually produce no impression upon us. Thus all ordinary changes of weather are preceded and accompanied by changes in the electrical condition of the atmosphere. This necessarily produces currents of electricity. Now we can ourselves hear these currents when of a certain volume or intensity, as in thunder and lightning, the discharge of an electric battery, and even the milder flow of the aurora, or from a fully charged Leyden jar. To a finer sense, the flow and turmoil of this subtiler fluid may be as obvious as that of the atmospheric air is to us, and thus inform the animals who possess it of changes and conditions of which we are insensible. Of the possibility of such a difference in the delicacy of hearing we are informed by the singular fact that certain very sharp sounds, perfectly audible to some persons, are never perceived by others.

CHAPTER VI. (W.)

OF SENSATION IN GENERAL.FEELING AND TOUCH. TASTE.

SMELL.

THE Connection between the animal and the external world is maintained by means of the several senses.

Whatever may be its natural desires and wants, these are necessary in order to their gratification. Their number and degree of perfection will correspond to the necessities and the situation of each individual. The animal which does not voluntarily seek its food needs not sight; the animal which cannot fly when pursued needs not to hear. There is the same harmony of relation between the senses and the powers called into action by them, that has already been pointed out between other circumstances in the structure of animals and the condition in which they have been placed. None have appetites or wants which there is not a provision for their indulging, and indulging with a certain degree of safety. There is always a correspondence, for example, between the appetite that suggests a particular kind of food, the senses that perceive it, the limbs which procure it, and the organs by which it is digested.

It makes no difference as to the number and perfection of the senses required, whether the presiding principle with which they are connected be intelligence or instinct. It has been argued that the wonderful operations brought about by certain animals, insects particularly, are not to be attributed chiefly to instinct, because, were they owing to a principle so mechanical, they would not require organs of sense so delicate as those they possess. 'If," says a writer on this subject, "insects in all their actions were directed mainly by their instinct, they might do as well without sight, hearing, smell, and touch." It might as well be urged that they could do without limbs, antennæ, mouth, and other external organs. But in truth the nature of the internal principle has nothing to do with that of the organs by which it is administered. It makes no difference in the bee, for example,

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whether it be induced to build its cell and provide its food by a blind instinct or a reasoning intelligence, so far as the organs by which it acts are concerned. In either case it requires organs of taste to perceive, as well as organs of motion to procure, the necessary materials; organs of touch to take note of the progress of its work as it goes on, as well as organs of motion to carry it on. The number and degree of perfection of the external senses are always strictly in proportion to the wants and desires of the internal governing principle, whatever that may be.

No animal possesses more than the five senses of sight, hearing, smell, taste, and touch; many are deficient in some of them, but none in all; and we may be sure that every one possesses all that are essential to the condition of existence in which it has been created.

In the lowest of the Radiata it is probable that there exists only a vague and indistinct perception of the qualities of external objects. Their senses may be resolved into a certain degree of feeling, or touch. We can hardly attribute to them either of the others distinctly, yet this one sense appears to be so modified as to be capable of performing some of the offices of the others. Their feelers or tentacula, for example, can determine whether the object which they encounter in the water is fit for their food. Touch them with a stick or the finger, and they shrink from it. Let them be touched by a worm, and they immediately grasp it and convey it to the mouth. This implies something of the attributes of smell and taste. So, too, they are influenced by light, and by those vibrations which constitute sound; and thus in a certain limited way they are influenced by the causes which excite all the senses. We cannot say that they have smell, taste, hearing, or sight, yet the sense of feeling is so modified as to perform, as far as it is needed, the office of them all.

As we ascend in the scale of being, the senses of smell and taste become more distinct from that of feeling, but it is not til' we arrive at the highest species among the Articulata and Mol lusca that we find them entirely distinct. Here, too, we first perceive the existence of the superior senses of sight and hearing. It is to be remarked that these, which furnish the only very distinct information concerning objects with which animals are not