Page:Popular Science Monthly Volume 34.djvu/282

270 while his body lies under the pier of the great telescope, must be moved with gratification at the complete fulfillment of his desire to build a telescope that should surpass all others in its achievements.



name of Lubbock will cause the reader to open this volume with an eager interest that will be amply justified. It is an extension of the investigations recorded by the author in his fascinating work on "Ants, Bees, and Wasps," going further into details of structure and function of the sense-organs of insects, together with some discussion of the intelligence displayed by higher animals. In the first half of the book, he gives us the results of his own observations, combined with what other investigators have learned as to the location of each sense in insects, and the structure of the organs in which each resides. He explains the purpose of this part of the work as follows: "While attempting to understand the manners and customs, habits and behavior of animals, as well as for the purpose of devising test experiments, I have found it necessary to make myself acquainted, as far as possible, with the mechanism of the senses, and the organs by means of which sensations are transmitted. With this object I had to look up a great number of memoirs, in various languages, and scattered through many different periodicals; and it seemed to me that it might be interesting, and save others some of the labor I had to undergo myself, if I were to bring together the notes I had made, and give a list of the principal memoirs consulted. I have accordingly attempted to give, very briefly, some idea of the organs of sense, commencing in each case with those of man himself." The list of memoirs to which he alludes is an extended one, occupying eight pages. He begins his descriptions with the sense of touch, "as being the one which is most generally distributed, and from which the others appear to have been in some cases developed. The senses are not, indeed, as already mentioned, always to be easily distinguished from one another; and it would seem that the same nerve may be capable of carrying different sensations according to the structure of the end organs." The inner skin of insects and crustaceans being covered with a layer of horny substance, the sensations of insects, excepting sight, are transmitted by means of hairs projecting through this hard integument. The organs of taste in insects are certain modified hairs situated either in the mouth itself, or on organs immediately surrounding it. Experiments which have been made seem to prove that the sense of smell resides partly in the antennæ and partly in the palpi. "This distribution would be manifestly advantageous. The palpi are more suited for the examination of food; while the antennæ are more conveniently situated for the perception of more distant objects." The antennæ probably serve partly as organs of touch, and some as organs of protection. The author deems it very probable also that some of them, at least, perform still another function, such as hearing, "while some of these peculiar antennal organs," he says, "though obviously organs of sense, seem to have no special adaptation to any sense of which we are cognizant." That insects may have senses of which we are not cognizant, he deems very probable. There are, without doubt, causes in nature which would produce sensations different from any we know of on organs capable of receiving them. For instance. Sir John has shown elsewhere that animals hear sounds which are beyond the range of our hearing, and can perceive the ultra-violet rays, which are invisible to our eyes. Sound and light are both produced by vibrations. The shrillest sound audible to us results from forty thousand vibrations a second, and no light that we can see is produced by less than four hundred million millions of vibrations in a second. "But between forty thousand vibrations in a second and four hundred million millions we have no organ of sense capable of receiving the impression. Yet between these limits any number of sensations may exist. We have five senses, and sometimes fancy that no others are possible. But it is obvious that we can not measure the infinite by our 