The first question to be asked is what are the causes to which these homogeneous parts owe their existence? The causes are various; and this whether the parts be solid or fluid. Thus one set of homogeneous parts represent the material out of which the heterogeneous parts are formed; for each separate organ is constructed of bones, sinews, flesh, and the like; which are either essential elements in its formation, or contribute to the proper discharge of its function. A second set are the nutriment of the first, and are invariably fluid, for all growth occurs at the expense of fluid matter; while a third set are the residue8 of the second. Such, for instance, are the faeces and, in animals that have a bladder, the urine; the former being the dregs of the solid nutriment, the latter of the fluid.
Even the individual homogeneous parts present variations, which are intended in each case to render them more serviceable for their purpose. The variations of the blood may be selected to illustrate9 this. For different bloods differ in their degrees of thinness or thickness, of clearness or turbidity10, of coldness or heat; and this whether we compare the bloods from different parts of the same individual or the bloods of different animals. For, in the individual, all the differences just enumerated distinguish the blood of the upper and of the lower halves of the body; and, dealing11 with classes, one section of animals is sanguineous, while the other has no blood, but only something resembling it in its place. As regards the results of such differences, the thicker and the hotter blood is, the more conducive12 is it to strength, while in proportion to its thinness and its coldness is its suitability for sensation and intelligence. A like distinction exists also in the fluid which is analogous to blood. This explains how it is that bees and other similar creatures are of a more intelligent nature than many sanguineous animals; and that, of sanguineous animals, those are the most intelligent whose blood is thin and cold. Noblest of all are those whose blood is hot, and at the same time thin and clear. For such are suited alike for the development of courage and of intelligence. Accordingly, the upper parts are superior in these respects to the lower, the male superior to the female, and the right side to the left. As with the blood so also with the other parts, homogeneous and heterogeneous alike. For here also such variations as occur must be held either to be related to the essential constitution and mode of life of the several animals, or, in other cases, to be merely matters of slightly better or slightly worse. Two animals, for instance, may have eyes. But in one these eyes may be of fluid consistency14, while in the other they are hard; and in one there may be eyelids15, in the other no such appendages16. In such a case, the fluid consistency and the presence of eyelids, which are intended to add to the accuracy of vision, are differences of degree. As to why all animals must of necessity have blood or something of a similar character, and what the nature of blood may be, these are matters which can only be considered when we have first discussed hot and cold. For the natural properties of many substances are referable to these two elementary principles; and it is a matter of frequent dispute what animals or what parts of animals are hot and what cold. For some maintain that water animals are hotter than such as live on land, asserting that their natural heat counterbalances the coldness of their medium; and again, that bloodless animals are hotter than those with blood, and females than males. Parmenides, for instance, and some others declare that women are hotter than men, and that it is the warmth and abundance of their blood which causes their menstrual flow, while Empedocles maintains the opposite opinion. Again, comparing the blood and the bile, some speak of the former as hot and of the latter as cold, while others invert17 the description. If there be this endless disputing about hot and cold, which of all things that affect our senses are the most distinct, what are we to think as to our other sensory18 impressions?
The explanation of the difficulty appears to be that the term ‘hotter’ is used in several senses; so that different statements, though in verbal contradiction with each other, may yet all be more or less true. There ought, then, to be some clear understanding as to the sense in which natural substances are to be termed hot or cold, solid or fluid. For it appears manifest that these are properties on which even life and death are largely dependent, and that they are moreover the causes of sleep and waking, of maturity19 and old age, of health and disease; while no similar influence belongs to roughness and smoothness, to heaviness and lightness, nor, in short, to any other such properties of matter. That this should be so is but in accordance with rational expectation. For hot and cold, solid and fluid, as was stated in a former treatise20, are the foundations of the physical elements.
Is then the term hot used in one sense or in many? To answer this we must ascertain21 what special effect is attributed to a hotter substance, and if there be several such, how many these may be. A body then is in one sense said to be hotter than another, if it impart a greater amount of heat to an object in contact with it. In a second sense, that is said to be hotter which causes the keener sensation when touched, and especially if the sensation be attended with pain. This criterion, however, would seem sometimes to be a false one; for occasionally it is the idiosyncrasy of the individual that causes the sensation to be painful. Again, of two things, that is the hotter which the more readily melts a fusible substance, or sets on fire an inflammable one. Again, of two masses of one and the same substance, the larger is said to have more heat than the smaller. Again, of two bodies, that is said to be the hotter which takes the longer time in cooling, as also we call that which is rapidly heated hotter than that which is long about it; as though the rapidity implied proximity22 and this again similarity of nature, while the want of rapidity implied distance and this again dissimilarity of nature. The term hotter is used then in all the various senses that have been mentioned, and perhaps in still more. Now it is impossible for one body to be hotter than another in all these different fashions. Boiling water for instance, though it is more scalding than flame, yet has no power of burning or melting combustible23 or fusible matter, while flame has. So again this boiling water is hotter than a small fire, and yet gets cold more rapidly and completely. For in fact fire never becomes cold; whereas water invariably does so. Boiling water, again, is hotter to the touch than oil; yet it gets cold and solid more rapidly than this other fluid. Blood, again, is hotter to the touch than either water or oil, and yet coagulates before them. Iron, again, and stones and other similar bodies are longer in getting heated than water, but when once heated burn other substances with a much greater intensity24. Another distinction is this. In some of the bodies which are called hot the heat is derived25 from without, while in others it belongs to the bodies themselves; and it makes a most important difference whether the heat has the former or the latter origin. For to call that one of two bodies the hotter, which is possessed26 of heat, we may almost say, accidentally and not of its own essence, is very much the same thing as if, finding that some man in a fever was a musician, one were to say that musicians are hotter than healthy men. Of that which is hot per se and that which is hot per accidens, the former is the slower to cool, while not rarely the latter is the hotter to the touch. The former again is the more burning of the two-flame, for instance, as compared with boiling water-while the latter, as the boiling water, which is hot per accidens, is the more heating to the touch. From all this it is clear that it is no simple matter to decide which of two bodies is the hotter. For the first may be the hotter in one sense, the second the hotter in another. Indeed in some of these cases it is impossible to say simply even whether a thing is hot or not. For the actual substratum may not itself be hot, but may be hot when coupled with heat as an attribute, as would be the case if one attached a single name to hot water or hot iron. It is after this manner that blood is hot. In such cases, in those, that is, in which the substratum owes its heat to an external influence, it is plain that cold is not a mere13 privation, but an actual existence.
There is no knowing but that even fire may be another of these cases. For the substratum of fire may be smoke or charcoal27, and though the former of these is always hot, smoke being an uprising vapour, yet the latter becomes cold when its flame is extinguished, as also would oil and pinewood under similar circumstances. But even substances that have been burnt nearly all possess some heat, cinders28, for example, and ashes, the dejections also of animals, and, among the excretions, bile; because some residue of heat has been left in them after their combustion29. It is in another sense that pinewood and fat substances are hot; namely, because they rapidly assume the actuality of fire.
Heat appears to cause both coagulation30 and melting. Now such things as are formed merely of water are solidified31 by cold, while such as are formed of nothing but earth are solidified by fire. Hot substances again are solidified by cold, and, when they consist chiefly of earth, the process of solidification32 is rapid, and the resulting substance is insoluble; but, when their main constituent34 is water, the solid matter is again soluble33. What kinds of substances, however, admit of being solidified, and what are the causes of solidification, are questions that have already been dealt with more precisely35 in another treatise.
In conclusion, then, seeing that the terms hot and hotter are used in many different senses, and that no one substance can be hotter than others in all these senses, we must, when we attribute this character to an object, add such further statements as that this substance is hotter per se, though that other is often hotter per accidens; or again, that this substance is potentially hot, that other actually so; or again, that this substance is hotter in the sense of causing a greater feeling of heat when touched, while that other is hotter in the sense of producing flame and burning. The term hot being used in all these various senses, it plainly follows that the term cold will also be used with like ambiguity36.
So much then as to the signification of the terms hot and cold, hotter and colder.
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1
permanently
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| adv.永恒地，永久地，固定不变地 | |
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serum
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| n.浆液，血清，乳浆 | |
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marrow
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| n.骨髓；精华；活力 | |
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4
analogues
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| 相似物( analogue的名词复数 )； 类似物； 类比； 同源词 | |
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enumerated
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| v.列举，枚举，数( enumerate的过去式和过去分词 ) | |
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analogous
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| adj.相似的；类似的 | |
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heterogeneous
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| adj.庞杂的；异类的 | |
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8
residue
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| n.残余，剩余，残渣 | |
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illustrate
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| v.举例说明，阐明；图解，加插图 | |
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turbidity
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| 混浊，混乱； 混浊度； 浊度 | |
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dealing
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| n.经商方法，待人态度 | |
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conducive
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| adj.有益的，有助的 | |
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mere
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| adj.纯粹的；仅仅，只不过 | |
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consistency
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| n.一贯性，前后一致，稳定性；(液体的)浓度 | |
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15
eyelids
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| n.眼睑( eyelid的名词复数 )；眼睛也不眨一下；不露声色；面不改色 | |
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appendages
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| n.附属物( appendage的名词复数 )；依附的人；附属器官；附属肢体（如臂、腿、尾等） | |
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17
invert
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| vt.使反转，使颠倒，使转化 | |
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18
sensory
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| adj.知觉的，感觉的，知觉器官的 | |
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19
maturity
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| n.成熟；完成；(支票、债券等)到期 | |
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20
treatise
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| n.专著；(专题)论文 | |
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21
ascertain
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| vt.发现，确定，查明，弄清 | |
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proximity
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| n.接近，邻近 | |
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23
combustible
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| a. 易燃的,可燃的; n. 易燃物,可燃物 | |
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intensity
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| n.强烈，剧烈；强度；烈度 | |
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25
derived
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| vi.起源；由来；衍生；导出v.得到( derive的过去式和过去分词 )；（从…中）得到获得；源于；（从…中）提取 | |
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26
possessed
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| adj.疯狂的；拥有的，占有的 | |
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27
charcoal
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| n.炭，木炭，生物炭 | |
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28
cinders
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| n.煤渣( cinder的名词复数 )；炭渣；煤渣路；煤渣跑道 | |
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29
combustion
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| n.燃烧；氧化；骚动 | |
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30
coagulation
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| n.凝固；凝结物 | |
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31
solidified
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| （使）成为固体，（使）变硬，（使）变得坚固( solidify的过去式和过去分词 )； 使团结一致； 充实，巩固； 具体化 | |
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32
solidification
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| 凝固 | |
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33
soluble
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| adj.可溶的；可以解决的 | |
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34
constituent
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| n.选民；成分，组分；adj.组成的，构成的 | |
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35
precisely
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| adv.恰好，正好，精确地，细致地 | |
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36
ambiguity
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| n.模棱两可；意义不明确 | |
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