discutient; and some are also useful in expectorations from the chest and menstrual discharges. But acrid juices would seem to differ from bitter, not only in possessing strong heat, but also in this, that all bitter things are not only hot but of a dry temperament like ashes, while in such acrid substances as are not bitter, there is often much humidity mixed, and therefore we use no few acrid things as articles of food. But since enough has been said respecting all the juices, it still remains to treat of the vapours. Most of the vapours, then, affect us similarly to the juices; for all acids, and likewise vinegar itself, move the senses of smell and taste in like manner; and acrid things, as garlic, onions, and the like, are pungent and offensive to the smell, no less than to the taste; so that, without tasting certain things, such as dung, we are confident that we know its quality, and therefore at once we abstain from them, because we repose confidence in the sense of smell. And of fragrant things, such as have become putrid and offend the smell, we straightway throw away, and do not attempt to taste; and in short, with regard to almost all things, the smell and taste are found to agree; and we refer each of them to two classes, calling the most of those substances which have smell, odorous, and fetid, and considering the odorous analogous to sweet things, and the fetid to such as are not sweet to the tongue, it would appear that from bodies which have no smell there is but little emitted, or at least that it is disproportionate to their bulk, as is the case with salt and sour things in particular; for the substance of sour things is of a dense and cold nature, so that it is natural that what is emitted from them should be small in quantity, thick, and terrene in its parts, so as not to reach the brain in respiration. Hence it is not safe to judge of their temperament from the smell as it is from the taste: for we know that things which are inodorous consist of thick particles, but it is not apparent how they are as to heat and cold; and that fragrant things consist of subtile particles, and are hot in their nature; but it is not shown by the smell but by the taste what is the degree of their tenuity and heat. The inequality of their substance is the cause why fragrant things give no certain indication of temperament; and therefore it is not safe to judge of all the qualities of the rose from its smell; but in taste all the parts of the bodies which are tasted fall equably upon the tongue, and each excites a sensation agreeably to its nature, namely, the sour part in it which is terrene consists of thick particles and is cold; the bitter, which consists of subtile parts and is hot; and third, the watery, which is necessarily cold. It is not safe then, as has been said, to form a judgment of all the powers of simple substances from the smell; but it is still more impracticable to estimate simple medicines