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besides) but for a Sample, I shall only insist upon the wonderful Provision in the Bill for the judging of the Food, and that is by peculiar serves lodged therein for that Purpose j small and less numerous in such as have the Assistance of another Sense, the Eye; but large, more numerous, and thickly branched about, to the very End of the Beak, in such as hunt for their Food out of Sight in the Waters, in Mud, or under Ground (e)i bso
And now if we compare the Organ and Act of Hearing, with those of Sight, we shall find, that the Conclave is to Hearing, as the Retina is to Sight; that sonorous Bodies make their Impressions thereby on the Brain, as visible Objects do by the Retina. Also, that as there is an Apparatus in the Eye, by the opening and shutting of the Pupil, to make it correspond to all the Degrees of Light, so there is in the Ear to make it conformableto all the Degrees of Sound, a noble Train of little Bones and Muscles in"Man, vc to strain and relax the Membrane, and at the fame Time to open and shut the Basis of the Stapes (the same as what I call the Opercttlum in Birds:) But in Birds, there is a more simple, but sufficient Apparatus for this Purpose, tender Cartilages, instead of Bones and Joints, to correspond to the various Impressions of Sounds, and to open and shut the Operculum. Besides which, I suspect the Ligament I mentioned, is only the Tendon of a Muscle, reaching to the inner Membrana Tympani, and joined thereto (as I find by a stricter Scrutiny) and not to the Cartilage, as I imagined. By this Muscle, the inner Membrane, and by Means of that the Outer also can be distended or relaxed, as it is in Man, by the Malleus and its Muscle, uc
(e) Flat-billed 'Birds, that grope for their Meat, have three Pair of Nerves, that come into their Bills, whereby they have 'that Accuracy to distinguifli what is proper for Food, and what to be rcjecled by their Taste, when they do not fee it. This ■was most evident in a Duck's Bill and Head; a Duck having larger Nerves that come into their Bills than Geese, or any other Bird that I have seen; and therefore quaffer and grope cut their Meat the most. But then I discovered none os these Nerves in round-bill'd Birds. But since, in my Anatomies in the Country, in a Rook, 1 first observed two Nerves that came down betwixt the Eyes into the upper Bill, but considerably
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smaller than any of the three Pair of Nerves, in the Sills of Ducks, but larger than the Nerves in any other round-bill'd Birds. And 'tis remarkable that these Birds, more than ans other round- bill'd Birds, seem to grope for their Meat in Cow.dung, &c. Mr. J. Clayton, in Philos. Transact. N°. io6.
/ observ'd three Pair of Nerves in all the broad-bill'd Birds that I could meet ivith, and in all such as feel for their Food out of Sight, M Snipes, Woodcocks, Curlews, Geese, Ducks, Tealsi Widgeons, &c. These Nerves are very large, equalling almost
the Optic Nerve in Thickness. Two are distributed nigh the
End of the upper Bill, and are there very much expanded, passing through the Bone into the Membrane, lining the Roof of the Mouth. Dr. A. Moulen. Ibid. N°. 199. Or both in Mr. Lowthorp's Abridg. V. %. p. 861, 861.
(/) The Gizzard is not only made very strong, especially in the Granivorous; but hath also a Faculty ot' Grinding what is therein. For which Purpose, the Bird swalloweth. rough Stones down, which, when grown smooth, are rejected and cast out of the Stomach, as useless. This Grinding may be heard in Falcons, Eagles, vc by laying the Ear close to them, when their Stomachs are empty, as the famous Dr. Harvey faith. De Generat. Exer. 7.
As to the Strength of the Gizzard, and the Use of Stones to the Digestion of Fowls, divers curious Experiments may be met with, try'd by Seigneur Redi, with glass BuDbies, iolid Glass, Diamonds, and other hard Bodies. See his £'.v/>. Nat.