Aristotle · a new plain-English translation from the original language
1| Why are fragrant seeds and plants diuretic? Is it because they are hot and fine, and things of this kind are diuretic? For the heat present in them quickly makes things fine, and scent is not corporeal—since even things that are not fragrant, such as garlic, are diuretic because of their heat, though more given to dissolving. Fragrant seeds are hot, because scent in general comes about through heat. But foul-smelling things are unconcocted; and to be diuretic a thing must be not only hot but also easily concocted, so that as it passes down together with the fluids it makes them fine. Why do mixed wines lose their scent faster than unmixed ones? Is it because the mixed wine is weaker than the unmixed? And the weaker is displaced by everything stronger than itself. Moreover, the mixed wine is more receptive than the unmixed. And it is easier for any quality whatsoever to come to belong to a thing, and for it to take on something it did not have before. So the unmixed wine is scented, while the mixed wine is scentless. Book 13. Problems Concerning Foul-Smelling Things Why does urine become more foul-smelling the longer it stays in the body, while excrement becomes less so? Is it because excrement dries out more the longer it stays (and the dry is less prone to putrefy), whereas urine thickens, and when fresh is more similar to the drink it originally was?
2| Why do foul-smelling things not seem to smell to those who have eaten them? Is it because, since the sense of smell is connected to the mouth through the palate, the perception quickly becomes full, and one no longer perceives the internal smell in the same way (for everyone perceives it at first, but once they have taken it in, no longer, as though it had grown into them), and the external smell, being similar, is masked by the internal one? Why are flowers more foul-smelling when rubbed? Is it because the earthy element in the flower becomes mixed in with the scent?
3| Why is it that none of the animals is fragrant except the leopard (and this one even to the wild beasts themselves—for they say the beasts enjoy its scent), while as they decay animals become foul-smelling, whereas many plants, both as they decay and even more as they wither, become more fragrant? Is it because the cause of foul smell is a kind of unconcocted residue? This is also why sweat in some people and at some times is of this sort, especially in those in whom it does not always arise from illnesses. And the flatulence and belching of those who have not concocted their food are foul-smelling. The same cause applies also to what is in the flesh, and to its analogue—I mean by analogue whatever is present in other animals in place of flesh. For there too, in some animals, there is an unconcocted residue; this, then, is the cause of foul smell in living animals, and of putrefaction as they decay. This is also why fat, bones, and hair are not foul-smelling, because the one is concocted, and the others do not have moisture. Plants, on the other hand, have no residue. Or rather, they too have something of the sort, but because plants are by nature dry and hot, is it that their moisture is more easily concocted and not muddy? This is shown also by the fact that the parts of the earth that are in hot regions are fragrant—Syria and Arabia—and the fragrant things from there, because they are dry and hot; and things of this kind do not putrefy. Animals are not of this kind and hot in the same way, so that their residues are unconcocted and foul-smelling, and likewise their exhalations; and when they decay their moisture putrefies, whereas plants' does not, for they do not have it.
4| Why are foul-smelling things more foul-smelling when hot than when cooled? Is it because scent is a kind of vapor and emanation? Vapor comes about through heat, and so does emanation, for it is a kind of motion, and heat is what produces motion; cold, on the contrary, is static and contractive, and tends downward, while heat, and all scents, tend upward, because they exist in air and because their organ of perception is above, not below—for scent, by reaching the brain, produces perception.
5| Why is it that if someone eats garlic, his urine smells, but though other things have a strong smell, eating them does not make the urine smell? Is it, as some of the followers of Heraclitus say, that just as there is exhalation in the universe as a whole, so there is exhalation in the body too, which then cools again and condenses — there as moisture, here as urine — and the exhalation from the food, mixing with the exhalation from which the urine arose, produces the smell? For the smell occurs when the food changes. Or ought all the other things that have strong smells to do the same, whereas in fact they do not? Further, things that recombine out of vapor do not return to their original state — wine, for example, comes from wine, but not water from water-vapor in the same way — so that this account too is false. Rather, the truth is that only what is inflating to the lower belly among things with a strong smell is at the same time diuretic, while other things act upward, such as cabbage, and produce wind. Or perhaps such things are not diuretic at all. Garlic has these three properties together: it is diuretic, it produces wind, and this happens below. The region around the genitals and the bladder shares in the effects of such things because of its proximity, and because it is full of wind — the tension of the genitals shows this. It is clear, then, that the residue from garlic, more than from anything else of this kind, reaches the bladder together with the wind, and this, mixing in, produces the smell of the urine.
6| Why do the mouths of those who have eaten nothing, but have fasted, smell more (this is called the smell of fasting), while the mouths of those who have eaten do not, though one would expect the opposite? Is it that when the belly is emptied, the air within it becomes hotter through lack of motion and putrefies the breath and the phlegmatic residues? A sign that it becomes hotter is that fasting also produces thirst more. In those who have eaten, the smell stops because it is weaker than the smell of the food; for the heat of the food overpowers the other heat, so that nothing untoward happens. Why is the armpit the most foul-smelling of places? Is it because it is the least ventilated? Foulness of smell occurs most in such places because putrefaction arises from the stillness of the fatty matter there — or because it is unmoved and unexercised. Why do people who smell of rank sweat become more foul-smelling when they anoint themselves with perfume? Is it because this happens in many cases — for example, when sour and sweet are mixed, the whole becomes sweeter? Also, everyone becomes more foul-smelling once they sweat, and perfume is heating; so it induces sweating. Why is the smell of the breath more foul and heavier in hunchbacked and stooped people? Is it because the region around the lung is closed in and drawn back out of its straight alignment, so that it is not well-ventilated, but the moisture and the breath putrefy more, being shut in inside?