The ground of this conceit is its swallowing down fragments of Iron, which men observing, by a froward illation, have therefore conceived it digesteth them; which is an inference not to be admitted, as being a fallacy of the consequent, that is, concluding a position of the consequent, from the position of the antecedent. For many things are swallowed by Animals, rather for condiment, gust or medicament, then any substantial nutriment. So Poultrey, and especially the Turkey, do of themselves take down stones; and we have found at one time in the gizzard of a Turkey no less then seven hundred. Now these rather concur unto digestion, then are themselves digested; for we have found them also in the guts and excrements; but their descent is very slow, for we have given them stones and small pieces of Iron, which eighteen days after we have found remaining in the gizzard. And therefore the experiment of _Langius_ and others might be fallible, whilst after the taking they expected it should come down within a day or two after. [SN: _How Cherry-stones may be thought to prevent surfets upon eating Cherries._] Thus also we swallow Cherry-stones, but void them unconcocted, and we usually say they preserve us from surfet; for being hard bodies they conceive a strong and durable heat in the stomack, and so prevent the crudities of their fruit: And upon the like reason do culinary operators observe, that flesh boiles best, when the bones are boiled with it. Thus dogs will eat grass, which they digest not: Thus Camels to make the water sapid, do raise the mud with their feet: Thus horses will knable at walls, Pigeons delight in salt stones. Rats will gnaw iron, and _Aristotle_ saith the Elephant swalloweth stones. And thus may also the _Ostrich_ swallow Iron; not as his proper aliment, but for the ends above expressed, and even as we observe the like in other Animals. And whether these fragments of Iron and hard substances swallowed by the _Ostrich_, have not also that use in their stomacks, which they have in other birds; that is, in some way to supply the use of teeth, by commolition, grinding and compression of their proper aliment, upon the action of the strongly conformed muscles of the stomack; as the honor'd Dr. _Harvey_ discourseth, may also be considered. What effect therefore may be expected from the stomack of an _Ostrich_ by application alone to further digestion in ours, beside the experimental refute of _Galen_, we refer it unto considerations above alledged; Or whether there be any more credit to be given unto the Medicine of _Ælian_, who affirms the stones they swallow have a peculiar vertue for the eyes, then that of _Hermolaus_ and _Pliny_ drawn from the urine of this Animal; let them determine who can swallow so strange a transmission of qualities, or believe that any Bird or flying Animal doth separately and distinctly urine beside the Bat.