We will therefore first take the word _deror_. This word signifies liberty, and is well applied to the Swallow, the bird of freedom. It is remarkable, by the way, how some of the old commentators have contrived to perplex themselves about a very simple matter. One of them comments upon the bird as being "so called, because it has the liberty of building in the houses of mankind." Another takes a somewhat similar view of the case, but puts it in a catechetical form: "Why is the swallow called the bird of liberty? Because it lives both in the house and in the field." It is scarcely necessary to point out to the reader that the "liberty" to which allusion is made is the liberty of flight, the bird coming and going at its appointed times, and not being capable of domestication. [Illustration: LOST FROM THE FLOCK.] Several kinds of Swallow are known in Palestine, including the true Swallows, the martins, and the swifts, and, as we shall presently see, it is likely that one of these groups was distinguished by a separate name. Whether or not the word _deror_ included other birds beside the Swallows is rather doubtful, though not at all unlikely; and if so, it is probable that any swift-winged insectivorous bird would be called by the name of Deror, irrespective of its size or colour. The bee-eaters, for example, are probably among the number of the birds grouped together under the word _deror_, and we may conjecture that the same is the case with the sunbirds, those bright-plumed little beings that take in the Old World the place occupied by the humming-birds in the New, and often mistaken for them by travellers who are not acquainted with ornithology. One of these birds, the _Nectarinia Oseæ_, is described by Mr. Tristram as "a tiny little creature of gorgeous plumage, rivalling the humming-birds of America in the metallic lustre of its feathers--green and purple, with brilliant red and orange plumes under its shoulders." In order to account for the singular variety of animal life which is to be found in Palestine, and especially the exceeding diversity of species among the birds, we must remember that Palestine is a sort of microcosm in itself, comprising within its narrow boundaries the most opposite conditions of temperature, climate, and soil. Some parts are rocky, barren, and mountainous, chilly and cold at the top, and acting as channels through which the winds blow almost continuously. The cliffs are full of holes, rifts, and caverns, some natural, some artificial, and some of a mixed kind, the original caverns having been enlarged and improved by the hand of man.