Page:Popular Science Monthly Volume 15.djvu/590

 that of natural history, gives that power of accurate deduction which is invaluable in the pursuit of every branch of knowledge. We all know, I may add, how much has been done in the researches of our time by applying the principle of comparison—comparison, for example, of the structure of living bodies as the basis of modern biology, the comparison of the structures of languages as the basis of philology. Depend upon it, then, that the observation and analogy which natural history is continually suggesting, as it is valuable for the purposes of science, so it has a lighter but a most graceful and civilizing use in supplying those analogies taken from the seen world and applicable to the unseen, assisting in giving to every work of the mind that grace and beauty which is just as appropriate and desirable, though it may not be so indispensable to it, as are the higher qualities of solidity and truth."

How the "Goat-Suckers" came by their Name.—Mr. A. R. Wallace calls attention to an interesting observation made by Charles Waterton, which throws some light on the origin of one of the superstitions of natural history. Ever since the time of Aristotle, at least, the belief has prevailed that the bird known as the "goat-sucker" (Caprimulgus) actually sucks goats or cows. According to Pliny, the goat-sucker "enters the fold and flies to the udders of the goats in order to suck the milk." The fact that the birds "fly to the udders" of the animals is confirmed by Waterton, but at the same time he shows how erroneous is the inference that they suck the milk. "lam fully persuaded," writes that ingenious observer, "that these innocent little birds never suck the herds, for when they approach them, and jump up at their udders, it is to catch the flies and insects there. When the moon shone bright I would frequently go and stand within three yards of a cow, and distinctly see the caprimulgus catch the flies on its udder." In another place he writes: "When the moon shines bright you may have a fair opportunity of examining the goat-sucker. You will see it close by the cows, goats, and sheep, jumping up every now and then under their bellies. Approach a little nearer—see how the nocturnal flies are tormenting the herd, and with what dexterity he springs up and catches them, as fast as they alight on the belly, legs, and udders of the animals. Observe how quiet they stand, and how sensible they seem of his good offices, for they neither strike him nor hit him with their tails, nor tread on him, nor try to drive him away as an uncivil intruder."

Geographical Distribution of Bats.—At a meeting of the "Scientific Societies of the Departments," lately held at Paris, a report of which is given in "La Nature," Dr. Trouessart, under the title of "Geographical Distribution of the Bats" (Cheiroptera), read a paper, of which the following is a summary: There are certain species of bats which pass the winter in a state of torpor in caverns or in abandoned quarries—for example, the horseshoe bat—or in the hollows of trees, under the roof-timbers of houses, or in crannies in the walls—as the Pipistrella, so common in cities, which, awakening during very mild winters, is sometimes seen flitting about in January. But it is an error to suppose that all bats hibernate. Many Cheiroptera migrate after the manner of birds, and this fact accounts for the reduction of the number of species from eight hundred to four hundred, as distinctions of species had been set up merely on the ground of the great distance between localities. Many species of bats seen in France are migratory, and are found there only in the summer months, having come in pursuit of the insects on which they subsist. Of twenty-five species occurring in Europe, at least twenty-two are found also in eastern Asia. Bats possess considerable power of flight. The flying fox (Pteropus rubricollis) of the tropical parts of the Old World can at one flight compass a distance of thirty leagues. This vigorous power of flight explains the presence of Cheiroptera in Australia, where they are the only native Monodelphs, as also in the islands of Polynesia and in New Zealand, a country rich in its avifauna, but which, with the exception of several species of bats, possesses no mammals save those purposely introduced by man, and the rats and mice brought by ships. Of the six families of the order Cheiroptera, the Phyllostomata are