And I believe that of all the powersOr properties. none hold less sway in the body than cold and heat. My reasons are these. So long as the hot and cold in the body are mixed up together, they cause no pain. For the hot is tempered and moderated by the cold, and the cold by the hot. But when either is entirely separated from the other, then it causes pain. And at that season, when cold comes upon a man and causes him some pain, for that very reason internal heat first is present quickly and spontaneously, without needing any help or preparation. The result is the same, whether men be diseased or in health. For instance, if a man in health will cool his body in winter, either by a cold bath or in any other way, the more he cools it (provided that his body is not entirely frozen) the more he becomes hotter than before when he puts his clothes on and enters his shelter. Again, if he will make himself thoroughly hot by means of either a hot bath of a large fire, and afterwards wear the same clothes and stay in the same place as he did when chilled, he feels far colder and besides more shivery than before. Or if a man fan himself because of the stifling heat and make coolness for himself, on ceasing to do this in this way he will feel ten times the stifling heat felt by one who does nothing of the sort.

Now the following is much stronger evidence still. All who go afoot through snow or great cold, and become over-chilled in feet, hands or head, suffer at night very severely from burning and tingling when they come into a warm place and wrap up; in some cases blisters arise like those caused by burning in fire. But it is not until they are warmed that they experience these symptoms. So ready is cold to pass into heat and heat into cold. I could give a multitude of other proofs. But in the case of sick folk, is it not those who have suffered from shivering in whom breaks out the most acute fever? And not only is it not powerful, but after a while does it not subside, generally without doing harm all the time it remains, hot as it is? And passing through all the body it ends in most cases in the feet, where the shivering and chill were most violent and lasted unusually long. Again, when the fever disappears with the breaking out of the perspiration, it cools the patient so that he is far colder than if he had never been attacked at all. What important or serious consequence, therefore, could come from that thing on which quickly supervenes in this way its exact opposite, spontaneously annulling its effect?Or power. Or what need has it of elaborate treatment?

An opponent may retort, But patients whose fever comes from ardent fevers,καῦσος was almost certainly a form of remittent malaria. See my (index). pneumonia, or other virulent disease, do not quickly get rid of their feverishness, and in these cases the heat and cold no longer alternate. Now I consider that herein lies my strongest evidence that men are not feverish merely through heat, and that it could not be the sole cause of the harm; the truth being that one and the same thing is both bitter and hot, or acid and hot, or salt and hot, with numerous other combinations, and cold again combines with other powers.Or properties. It is these things which cause the harm. Heat, too, is present, but merely as a concomitant, having the strength of the directing factor which is aggravated and increases with the other factor, but having no powerOr effect. greater than that which properly belongs to it.

That this is so is plain if we consider the following pieces of evidence. First we have the more obvious symptoms, which all of us often experience and will continue so to do. In the first place, those of us who suffer from cold in the head, with discharge from the nostrils, generally find this discharge more acrid than that which previously formed there and daily passed from the nostrils; it makes the nose swell, and inflames it to an extremely fiery heat, as is shown if you put your hand upon it.Or, with the MSS. reading, And if you keep putting your hand to it, and the catarrh last a long time, etc. And if the disease be present for an unusually long time, the part actually becomes ulcered, although it is without flesh and hard. But in some way the heat of the nostril ceases, not when the discharge takes place and the inflammation is present, but when the running becomes thicker and less acrid, being matured and more mixed than it was before, then it is that the heat finally ceases. But in cases where the evil obviously comes from cold alone, unaccompanied by anything else, there is always the same change, heat following chill and chill heat, and these supervene at once, and need no coction. In all other instances, where acrid and unmixed humours come into play, I am confident that the cause is the same, and that restoration results from coction and mixture.

Again, such discharges as settle in the eyes, possessing powerful, acrid humours of all sorts, ulcerate the eyelids, and in some cases eat into the parts on to which they run, the cheeks and under the eyes; and they rupture and eat through the covering of the eyeball. But pains, burning and intense inflammation prevail until the discharges are concocted and become thicker, so that rheum is formed from them. This coction is the result of mixture, compounding and digestion. Secondly, the discharges that settle in the throat, giving rise to soreness, angina, erysipelas and pneumonia, all these at first emit salt, watery and acrid humours, whereby the diseases are strengthened. But when they become thicker and more matured, and throw off all trace of their acridness, then the fevers too subside with the other symptoms that distress the patient. We must surely consider the cause of each complaint to be those things the presence of which of necessity produces a complaint of a specific kind, which ceases when they change into another combination. All conditions, then, resulting from heat or cold pure and simple, with no other powerOr quality. as a factor, must cease when heat changes into cold or cold into heat. This change takes place in the manner I have described above. Moreover, all other complaints to which man is liable arise from powers.Or qualities. Thus, when there is an out-pouring of the bitter principle, which we call yellow bile, great nausea, burning and weakness prevail. When the patient gets rid of it, sometimes by purgation, either spontaneous or by medicine, if the purging be seasonable he manifestly gets rid both of the pains and of the heat. But so long as these bitter particles are undissolved, undigested and uncompounded, by no possible means can the pains and fevers be stayed. And those who are attacked by pungent and acrid acids suffer greatly from frenzy, from gnawings of the bowels and chest, and from restlessness.Or distress. No relief from these symptoms is secured until the acidity is purged away, or calmed down and mixed with the other humours. But coction, alteration, thinning or thickening into the form of humours through other forms of all sorts (wherefrom crises also and fixing their periods derive great importance in cases of illness)—to all these things surely heat and cold are not in the least liable. For neither could either ferment or thicken. †For what shall we call it? Combinations of humours that exhibit a powerOr property. that varies with the various factors.There are many reasons for supposing that this sentence is either (a) in its wrong place, or (b) an interpolation. It seems quite irrelevant, and αὐτῶν should grammatically refer to τὸ θερμὸν and τὸ ψυχρόν, but there is not a crasis of these, but only of χυμοί. Hot and cold mixed produce only hot or cold, not a crasis. The sentence might be more relevantly placed at the end of Chapter XVIII, as an explanation of the process ἀποκαθίστασθαι πεφθέντα καὶ κρηθέντα. But transposition will not remove the other difficulties of the sentence. What is αὐτό? Health or disease? If health, then there is but one crasis producing it, not many, having various properties. If disease, then it cannot be a crasis at all, but ἀκρασία. Finally, ἄλλην πρὸς ἄλληλα is dubious Greek. The whole sentence looks like an interpolation, though it is hard to say why it was introduced. The scribe of M seems to have felt the difficulties, for he wrote κρῆσις, πλὴν for ἄλλην, and ἔχουσα.† Since the hot will give up its heat only when mixed with the cold, and the cold can be neutralized only by the hot. But all other components of man become milder and better the greater the number of other components with which they are mixed. A man is in the best possible condition when there is complete coction and rest, with no particular powerOr property. displayed. About this I think that I have given a full explanation.

Certain physicians and philosophers assert that nobody can know medicine who is ignorant what a man is; he who would treat patients properly must, they say, learn this. But the question they raise is one for philosophy; it is the province of those who, like Empedocles, have written on natural science,About nature, how the universe was born and grew out of primal elements. We might almost trauslate φὐσις by evolution. what man is from the beginning, how he came into being at the first, and from what elements he was originally constructed. But my view is, first, that all that philosophers or physicians have said or written on natural science no more pertains to medicine than to painting.Or, perhaps, pertains even less to medicine than to literature. I also hold that clear knowledge about natural science can be acquired from medicine and from no other source, and that one can attain this knowledge when medicine itself has been properly comprehended, but till then it is quite impossible—I mean to possess this information, what man is, by what causes he is made, and similar points accurately. Since this at least I think a physician must know, and be at great pains to know, about natural science, if he is going to perform aught of his duty, what man is in relation to foods and drinks, and to habits generally, and what will be the effects of each on each individual. It is not sufficient to learn simply that cheese is a bad food, as it gives a pain to one who eats a surfeit of it; we must know what the pain is, the reasons for it, and which constituent of man is harmfully affected. For there are many other bad foods and bad drinks, which affect a man in different ways. I would therefore have the point put thus:—Undiluted wine, drunk in large quantity, produces a certain effect upon a man. All who know this would realise that this is a power of wine, and that wine itself is to blame,See Appendix on p. 64. and we know through what parts of a man it chiefly exerts this power. Such nicety of truth I wish to be manifest in all other instances. To take my former example, cheese does not harm all men alike; some can eat their fill of it without the slightest hurt, nay, those it agrees with are wonderfully strengthened thereby. Others come off badly. So the constitutions of these men differ, and the difference lies in the constituent of the body which is hostile to cheese, and is roused and stirred to action under its influence. Those in whom a humour of such a kind is present in greater quantity, and with greater control over the body, naturally suffer more severely. But if cheese were bad for the human constitution without exception, it would have hurt all. He who knows the above truths will not fall into the following errors.