constitution to preclude such a supposition; and not only that, but we know in the case of Pallas's sand-grouse, and many other accidental visitors, that they have at once adapted themselves to the food afforded by the country, although perfectly new to them. How far such influences, acting on generations and for long periods, do effect the external appearances or internal structure of a species, are points not yet clearly determined; but doubtless, as the geographical distribution and migrations of animals become better known, so will many difficulties of that nature be cleared up. Of the vast hosts of birds that cross the Mediterranean annually not a few perish on their way, and their bodies are thrown up on the beach; many arrive only to die, as we can testify from our own observations along the shores of Malta, where we have picked up numerous warblers that had been either drowned on their passage or died on the rocks, or had dashed themselves at night against the fortifications and light-houses. "The beacon blaze illures The bird of passage, till he madly strikes Against it, and beats out his weary life." The quail on its way to Europe in spring, or Africa in autumn, is often borne back by a strong head-wind to the country it had just left; and we have repeatedly noticed that a strong sirocco in September scarcely ever fails in throwing abundance of quail {61} on the southeast coast of Malta, in the same way that a powerful gregale brings in many that had been bent on an opposite direction. We now come to observe that extraordinary intelligence whereby swallows, for instance, are enabled year after year to return to the same nest. Taking into consideration the long absence, the dangers and difficulties incident to the voyage, it seems incredible that any animal not human can be capable, after nearly eight months' sojourn in central Africa, to return in spring to a farm-yard in the midland counties of England; and still more wondrous, as recorded in "Yarrell's British Birds," that several swifts, undeniably marked, returned not only for three years in succession, but one of the number was caught in the same locality at the expiration of seven years. Here, then, are displayed effects of memory and perception--in fine, a wondrous manifestation of intellect, which, under the vague name of instinct, has been applied, we think too indiscriminately, to such-like mental phenomena among the lower animals.