by Aristotle
These then are the reasons for the changes in colour produced by dyeing.
5 · As for hair and feathers and flowers and fruit and all plants, it is abundantly clear that all the changes of colour which they undergo coincide with the process of maturation. But what the origins of colour in the various classes of [15] plants are, and what kinds of changes these colours undergo, and from what materials these changes are derived, and the reasons why they are thus affected, and any other difficulties connected with them—in considering all these questions we must start from the following premisses. In all plants the original colour is [20] herb-green; thus shoots and leaves and fruit begin by taking this colour. This can also be seen in the case of rain-water; when water stands for a considerable time and then dries up, it leaves a herb-green behind it. So it is intelligible why herb-green is the first colour to form in all plants. For all water in process of time first turns [25] yellow-green on blending with the rays of the sun; it then gradually turns black, and this further mixture of black and yellow-green produces herb-green. For, as has already been remarked, moisture becoming stale and drying up of itself turns black. [30] This can be seen, for example, on the stucco of reservoirs; here all the part that is always under water turns black, because the moisture, as it cools, dries up of itself, but the part from which the water has been drawn off, and which is exposed to the sun, becomes herb-green, because yellow mingles with the black. Moreover, with [795a1] the increasing blackness of the moisture, the herb-green tends to become very deep and of a leek-green hue. This is why the old shoots of all plants are much blacker than the young shoots, which are yellower because the moisture in them has not yet [5] begun to turn black. For, the growth being slow and the moisture remaining in them a long time, owing to the fact that the liquid, as it cools, turns very black, a leek-green is produced by blending with pure black. But the colour of shoots in [10] which the moisture does not mix with the rays of the sun, remains white, unless it has lasted a long time and dried and turned black at an earlier stage. In all plants, therefore, the parts above the ground are at first of a yellow-green, while the parts under the ground, namely the stalks and the roots, are white. The shoots, too, are [15] white as long as they are underground, but if the earth be removed from round them, they turn herb-green; and all fruit, as has been already said, becomes herb-green at first, because the moisture, which passes through the shoots into it, has a natural tendency to assume this colour and is quickly absorbed to promote the [20] growth of the fruit. But when the fruit ceases to grow because the liquid nourishment which flows into it no longer predominates, but the moisture on the contrary is consumed by the heat—then it is that all fruit becomes ripe; and the [25] moisture already present in it being heated by the sun and the warmth of the atmosphere, each species of fruit takes its colour from its juice, just as dyed material takes the hue of the dye. This is why fruits colour gradually, those parts of them which face the sun and heat being most affected; it is also the reason why all fruits [30] change their colour with the changing seasons. This is evident; for all fruits, as soon as they begin to ripen, change from herb-green to their natural colour. They become white and black and grey and yellow and blackish and dusky and crimson and [795b1] wine-coloured and saffron—in fact, assume practically every variety of colour. Since most hues are the result of the blending of several colours, the hues of plants [5] must certainly also be due to the same blends; for the moisture percolating through the plants washes and carries along with it all the ingredients on which their colours depend. When this moisture is heated up by the sun and the warmth of the atmosphere at the time of the ripening of the fruit, each of the colours forms [10] separately, some quickly and some slowly. The same thing happens in the process of dyeing with purple; when, after breaking up the shell and washing all the moisture from it, they pour it into earthenware vessels and boil it, at first no definite colour is noticeable in the dye, because, as the liquid boils more and more and the colours still [15] remaining in the vessels mix together, each of the hues gradually undergoes a great variety of alterations; for black and white and brown and hazy shades appear, and finally the dye all turns purple, when the colours are sufficiently boiled up together; [20] so as a result of the blending no other colour is separately noticeable. This is just what happens with fruit. In many instances, because the maturing of all the colours does not take place simultaneously, but some colours form earlier and others later, [25] changes from one to another take place, as in the case of grapes and dates. Some of these are crimson at first; but when black colour forms in them, they turn to a wine colour, and in the end they become a dark-bluish hue when the crimson is finally [30] mixed with a large quantity of pure black. For the colours which appear late, when they predominate, change the earlier colours. This is best seen in black fruits; for broadly speaking most of them, as has already been remarked, first change from [796a1] herb-green to a pinkish shade and become reddish, but quickly change again from the reddish hue and become dark blue because of the pure black present in them. [5] The presence of crimson is proved by the fact that the twigs and shoots and leaves of all such plants are crimson, because that colour is present in them in large quantities; while that black fruits partake of both colours is clear from the fact that their juice is always a wine colour. Now the crimson hues come into existence at an [10] earlier stage in growth than the black. This is clear from the fact that pavement upon which there is any dripping, and, generally speaking, any spot where is a slight flow of water in a shady place, always turns first from herb-green to a crimson colour, and the pavement looks as though blood had lately been shed over all the [15] portion of it on which the herb-green colour has matured; then finally this also becomes very black and of a dark-bluish colour. The same thing happens in the case of fruit. That change in the colour of fruit occurs by the formation of a fresh colour, [20] which ousts the earlier one, can easily be seen from the following examples. The fruit of the pomegranate and the petals of roses are white at first, but in the end, when the juices in them are beginning to be tinged as they mature, they alter their colours and change to violet and crimson hues. Other parts of plants have a number [25] of shades, for example the juice of the poppy and the scum of olive oil; for this is white at first, as is the fruit of the pomegranate, but, after being white, it changes to crimson, and finally mingling with a large quantity of black it becomes a [30] dark-bluish hue. So, too, the petals of the poppy are crimson at their ends, because the process of maturation takes place quickly there, but at their base they are black, because this colour is already predominant at the end; just as it predominates in the [796b1] fruit, which also finally becomes black.
In the case of plants which have only one colour—white, for example, or black or crimson or violet—the fruit always keeps a single kind of colour, when once it has [5] changed from herb-green to another colour. Sometimes the blossoms are of the same colour as the fruit—as, for instance, in the pomegranate, the fruit and blossoms of which are both crimson; but sometimes they are of very dissimilar [10] hues—as, for example, in the bay-tree and the ivy, whose blossoms are always yellow, but their fruit respectively black and crimson. The same is true of the apple-tree; its blossom is white with a tinge of pink, while its fruit is yellow. In the poppy the flower is crimson, but the fruit may be black or white, according to the [15] different time at which the juices present in the plant ripen. The truth of the last statement can be seen from many examples; for, as has been said, some fruits come to differ greatly as they ripen. This is why the odours and flavours of flowers and [20] fruits differ so much. This is still more evident in the actual blossoms. For part of the same petal may be black and part crimson, or, in other cases, part white and part purplish. The best example of all is the iris; for its blossom shows a great [25] variety of hues according to the different states of maturation in its different parts, just as grapes do when they are already ripening. Therefore the extremities of blossoms always ripen most completely, whilst the
parts near the base have much [30] less colour; for in some cases the moisture is, as it were, burnt out before the blossom undergoes its proper process of maturation. It is for this reason that the blossoms remain the same in colour, while the fruit changes as it grows riper; for the former, owing to the presence of only a small amount of nutriment, soon mature, while the [797a1] fruit, owing to the presence of a large quantity of moisture, changes as it ripens to all the various hues which are natural to it. This can also be seen, as has already been remarked, in the process of colour-dyeing. When in dyeing purple they put in [5] the colouring matter from the vein of the purple-fish, at first it turns brown and black and hazy; but when the dye has been boiled sufficiently, a vivid, bright violet appears. So it must be from similar reasons that the blossoms of a plant frequently [10] differ in colour from its fruit, and that some pass to a stage beyond, whilst others never attain to their natural colour, according as they do or do not mature thoroughly. For these reasons, then, blossoms and fruit differ from one another in [15] their colouring. The leaves of most trees turn yellow in the end, because, owing to the failure of nutriment, they become dried up before they change to their natural colour; just as some of the fruits also which fall off are yellow in colour, because here too nutriment fails before they mature. Furthermore, corn and in fact all [20] plants turn yellow in the end. This change of colour is due to the fact that the moisture in them no longer turns black owing to the rapidity with which it dries up. As long as it turns black and blends with the yellow-green, it becomes herb-green, as has already been said; but, since the black is continually becoming weaker, the [25] colour gradually reverts to yellow-green and finally becomes yellow. The leaves of the pear-tree and the arbutus and some other trees become crimson when they mature; but the leaves even of these, if they dry up quickly, turn yellow, because the nutriment fails before maturity is reached. It seems very probable then that the [30] differences of colour in plants are due to the above causes.
6 · The hairs, feathers, and hides, whether of horses, cattle, sheep, human beings, or any other class of animals, grow white, grey, reddish, or black for the [797b1] same reason. They are white when the moisture which contains their proper colouring is dried up in the course of maturation. They are black, on the other hand—as was the case in the other form of life—when, during their growth, the [5] moisture present in the skin settles and becomes stale owing to its abundance, and so turns black; in all such cases skin and hide become black. They are grey, reddish, and yellow, and so on, when they have dried up before the moisture in them has [10] completely turned black. Where the process has been irregular, their colours are correspondingly variegated. So in all cases they correspond in colour to the hide and skin; for when men are reddish in colouring, their hair too is of a pale red; when they [15] are black, it is black; and if white leprosy has broken out over some part of the body, the hair on that portion is also always white, like the marking on dappled animals. Thus all hair and feathering follows the colour of the skin, both regional hair and hair which is spread over the whole body. So, too, with hoofs, claws, beaks, and [20] horns; in black animals they are black, in white animals they are white, and always because the nutriment percolates through the skin to the outer surface. A number of facts prove that this is the true cause. For example, the heads of all young children [25] are at first reddish owing to scanty nutriment; that this is so is clear from the fact that the hair of infants is always weak and thin and short at first; but as they grow older, the hair turns black, when the nutriment which flows into them settles owing [30] to its abundance. So, too, with the pubes and beard; when the hair is just beginning to grow on the pubic region and chin, it also is reddish at first, because the moisture in it, being scanty, quickly dries up, but as the nutriment is carried more and more to those regions the hair turns black. But the hair on the rest of the body remains [798a1] reddish for a considerable time owing to lack of nutriment; for as long as it is growing, it keeps on turning black like the pubes and the hair of the head. This is clear from the fact that hairs which have any length are generally blacker near the body and yellower towards the ends, because the moisture which reaches these parts [5] of them is very scanty and soon dries up. The feathers, too, of black birds are in all cases darker near the body and lighter at the ends. The same is the case with the [10] parts about the neck and, generally speaking, any part which receives scanty nutriment. This can be illustrated by the fact that before turning grey all hair changes colour and becomes reddish, because the nutriment again fails and dries up [15] quickly; finally it becomes white, because the nutriment in it is completely matured before the moisture turns black. This is most evident in the case of beasts of burden; here the hair always turns white, for in those parts because, owing to the feebleness [20] of the heat, they cannot draw up as much nourishment as the rest of the body, the moisture quickly dries up and turns white. So men tend especially to turn grey in the region of the temples, and generally speaking in any part which is weak and ailing. So, too, white is the colour to which more than any other a change tends to take place in instances of deviation from natural colour. For example, a hare has been [25] known before now to be white—while black hares have also been seen—and similarly white deer and bears have sometimes occurred; similarly white quails, partridges, and swallows. For all these creatures, when weak in their growth, come to maturity too soon owing to lack of nutriment, and so turn white. Similarly some infants at birth have white hair and eyelashes and eyebrows, a circumstance which [30] normally occurs when old age is coming on and is then clearly due to weakness and lack of nutriment. Therefore in most classes of animals the white specimens are weaker than the black; for, owing to lack of nutriment, they mature before their [798b1] growth is complete, and so turn white, just as does fruit when it is unhealthy; for fruit is still more apt to get mature through weakness. But when animals grow white [5] and at the same time are far superior to the rest of their species, as is the case with horses and dogs,8 the change from their natural colour to white is due to generous nutriment. For in such animals the moisture, not settling long, but being absorbed in the process of growth, does not turn black. Such animals are soft and well covered [10] with flesh, because they are well nourished, and white hairs, therefore, never change colour. This is clear from the fact that black hairs, when the nutriment in them fails and matures too completely, turn reddish before they grow grey, but finally turn [15] white. Yet some people hold that hair always turns black because its nutriment is burnt up by heat, just like blood and all other substances; but they are in error, for some animals are black from birth—dogs, for example, and goats, and oxen, and, [20] generally speaking, those creatures whose skin and hair get nutriment from the very first—but they are less black as they get older. If their supposition were correct this ought not to be the case, but it would necessarily follow that the hair of all animals would turn black at their prime, when heat predominates in them, and that they would be more likely to be grey at first. For in the beginning the heat is always [25] much weaker than at the time when the hair begins to turn white. This is clear in the case of white animals also. Some of them are very white in colour at birth, those, [30] namely, which at first have an abundance of nutriment, the moisture in which has not been prematurely dried up; but as they grow older their hair turns yellow, because less nutriment afterwards flows into it. Others are yellow at first and are [799a1] whitest at their prime. Similarly birds change colour when the nutriment in them fails. That this is the case can be seen in the fact that in all these animals it is the parts round the neck, and, generally speaking, any parts which are stinted when the [5] nourishment is scanty, which turn yellow; for it is clear that, just as reddish colour turns black and vice versa, so white turns yellow and vice versa. This happens also in plants, some of which revert from a later stage in the process of maturation back again to an earlier stage. The best illustration of this is to be found in the [10] pomegranate. At first its seeds are crimson, as are a
lso its leaves, owing to the small amount of nourishment which matures completely; afterwards they turn to a herb-green, because a quantity of nutriment flows into them and the process of maturation is less able to predominate than before; but in the end the nutriment [15] does mature and the colour reverts to crimson.