at first as he does his limbs, instinctively, but without distinct purpose. By and by he discovers that certain efforts are accompanied by certain sounds, and this association is gradually followed by a succession of others; but his advance in the knowledge of sounds is far more slow than in that of colors, and principally for the reason just named, that color is a constant, whilst sound is only an occasional, attribute of bodies. It is also difficult to refer sounds to their origin, and the touch does not in this case aid us as it does in that of the eye. We cannot be sure that the body we touch is that which has emitted a sound. It is only after a considerable advance has been made in the education of the sense of sight, that that of hearing arrives at a tolerable degree of accuracy.

But though thus so late in its development, hearing ultimately becomes as important as seeing. Merely as animals, having certain wants to satisfy and desires to gratify, there is no doubt of the greater value to us of the sense of sight. But when man is regarded as an intellectual, moral, and social being, the sense of hearing assumes an increased relative importance. Upon this depends voice and language, the medium by which we communicate with the rest of our species. By it we receive much of our knowledge; by it the intellect is cultivated; by it the emotions, affections, and passions are excited, and by the voice, which is trained only by its aid, they are expressed. It is the great agent of human intercourse; and, although human ingenuity has devised means of obtaining the entrance of language to the mind through the senses of sight and touch, yet this is but a secondary use. The origin of language depends upon the sense of hearing.

It is worthy of remark, that after the senses are completely educated we mainly depend, in our intercourse with the external world, upon those from which we originally get the most imperfeet information,-sight and hearing. It is difficult to imagine, were we confined to these two from the first, how we could make any progress in our knowledge of other things than ourselves. So far as we can judge, the scene about us must appear like a dream, a vain and unsubstantial vision.

There are various other relations of the senses in man that it would be interesting to point out, but this would lead to too wide

a discussion. It is only necessary to remark further, that, although in this analysis of their office and education they have been spoken of as developed and educated in succession, this is not strictly true. The sight does not wait till the touch is perfected, nor the hearing till both have been fully instructed. There is the order of precedence which has been pointed out in the degree of progress, but the education of all begins as soon as they begin to receive impressions, and advances with a rapidity proportioned to the necessities of existence, and to the development of the internal powers to which they are subservient.

Among the lower animals, there is a great difference in the capacity for the exercise of the senses which they manifest at birth, and the amount of education necessary in order to their perfection. Generally, however, they come speedily to their perfect use; and that capacity for employing them, which in man is the result of a course of training, is in them instinctively possessed. The chicken, as soon as it has left the egg, can not only see and hear, but can judge at once of the distance, position, and magnitude of bodies, of the direction and import of sounds, and can direct its voluntary movements in conformity with this knowledge. This difference depends not upon the organs of sense and the organs of motion, but upon the internal principle with which these are associated and by which they are directed. The chick comes into existence possessed of an instinct already instructed and informed. Little is left to intelligence or education. The infant, on the contrary, has few informed instincts, but it has instead an intelligent principle existing in embryo, destitute of knowledge, and capable of arriving only by a slow and laborious, though still an instinctive, process at the same capacity for receiving and judging of the impressions on the senses.

The senses, taken all together, in man are superior to those of other animals, simply because he possesses the best means of educating them; and this is done chiefly by the perfection of his touch, in which he excels all, whilst in particular senses he is excelled by many. Quadrupeds derive impressions through the organ of smell, of which we have no adequate conception. In the dog, for example, it is the test to which he brings every new

object. He does not trust to sight or hearing alone. He judges by his smell, as man does by sight. The fondness which he at once shows for some individuals seems to be of the same nature as the agreeable impression often made upon us at the first sight of a stranger. The dog who has been long absent from his master is never satisfied of his identity till he has subjected him to this ordeal. In Birds probably the sight is predominant, and in Fishes hearing. Still there is much that is difficult to account for, in regard to the information derived by animals so far as we know—from the senses they have in common with us. How do birds direct their course in their long migrations, and arrive always safely at their destined end? How do fishes pass from sea to sea and up the course of rivers with such unerring certainty, through a waste of waters which can bear no marks for their guidance? Man does similar things only as the result of long experience, careful observation, and by bringing to his aid the discoveries which science has slowly accumulated. The history of the whole animal creation is full of phenomena really as wonderful as these.

So remarkable are some of those exhibited by insects, that it has been even supposed that they may possess senses which we do not; at any rate, it is certain that they derive information from external objects, to which we are always strangers. Still the organs by which this is done have not been detected, and it is not even certain, with the exception of the eye, what is the distinctive function of the several parts which are obviously concerned in conveying to them information about sensible objects. Facts have been stated which render it probable that the antennæ are the seat of hearing; but beyond this there are also circumstances which appear to imply that they are not only the seat of combined powers of sensation, of which we have no clear conception, but also of reciprocal powers of communication. Some examples of this sort will be found in other parts of this work in relation to ants. Huber records a very remarkable one of bees. When the queen is taken from a hive, great consternation is manifested as soon as the loss becomes known through the community, and every absent individual, as he returns, is at once informed, and takes part in the alarm. In order to determine how the fact was

communicated from one to another, a hive was divided into two parts, by a grating which prevented the contact of the antennæ of the animals on its two sides. Those remaining with the queen continued perfectly tranquil. Those upon the other side of the grating were thrown into a state of great agitation, and after a while, not discovering their ruler, proceeded as usual to take means for the preparation of a successor. The division was then so arranged that the antennæ could be brought in contact, but no other part. No consternation ensued, but a constant communication was maintained across the grating, by touching the antennæ, and the queen was stationed at the dividing line, constantly occupied in answering the inquiries and quieting the apprehensions of her faithful subjects.

Bees, like dogs, distinguish persons, remember them, and exhibit a singular preference for some and antipathy to others. Some persons, taking advantage of this peculiarity, have been able to handle them with impunity, and by making captive the queen and removing her from place to place, have caused the whole swarm to settle upon and to move over different parts of their bodies.

Many insects are extremely susceptible to the influences of weather, and this may probably be due to that peculiar compound sensibility of the antennæ just referred to. Ants are highly endowed in this particular. Although they daily bring out their larvæ to warm them in the sun, they never suffer themselves to be overtaken by rain. Many other insects are aware of the approach of foul weather, before any signs of it are obvious to us, Bees foresee a shower long before its approach, and return suddenly to their hives. When they wander far from home and remain abroad late in the evening, it is an indication that the ensuing day will be fine. When, on the contrary, they remain near at hand, and are seen frequently going and returning, rain is pretty sure to follow, though we can discern no sign of its approach. Perhaps this extreme sensibility may be connected with a hygrometric property of the antennæ, or a power of appreciating electrical changes in the atmosphere.

CHAPTER IX. (W.)

REPRODUCTION AND TRANSFORMATION.

THE production of one living thing from another, and its first coming into existence, is a mystery into the intimate nature of which we cannot hope to penetrate. We are well acquainted with some of the details of the process, but the mode in which the principle of life is transmitted from one being to another, and by which it is able to convert common matter into a living tissue, eludes our observation. The medium of this transmission in the case of the plant is a seed, and in the animal an egg. The nature and purpose of these two bodies is essentially similar. Each is the germ of the new creation. The circumstances in which they differ have been before pointed out, but those in which they resemble each other are quite as striking.

The egg may be developed and nourished within the body of the mother, in which case the young are born alive; but in byfar the larger part of the animal kingdom it is thrown out by the parent, and goes through a subsequent process, called incubation. A certain degree of heat is necessary to this, as is shown by the fact that some degree of cold will arrest it.* The eggs of many insects are laid in the fall, but remain dormant through the winter, the heat of spring or summer being necessary to their development. Among birds, a more equal and constant as well as a higher degree of warmth is necessary, and this is usually supplied by the body of the mother. In hot climates the external

* In birds, a heat nearly approaching that of the parent animal is required. In reptiles, fishes, insects, &c., the temperature of the medium in which they live at the breeding season is sufficient. How low the temperature may fall without arresting the process in the lower classes is not certain. In the arctic regions, during the summer, insects appear in great numbers when the thermometer rises to 45° in the daytime, although during some part of every day it falls many degrees below the freezing point. Probably, therefore, the embryo is frozen during some part of every day during the whole process of incuoation; but it is not likely that any active progress ever takes place below 32°, if so low as this.