gestation is seven, eight, or nine months, or ten at the outside, though some have even advanced as far as the eleventh month.
5. If any are born before the seventh month, they never live. Those of seven months are the first that are developed, but these are usually weakly, wherefore, also, they wrap them in wool. Many of these infants have the passages, as the ears and nostrils, imperforate. As they grow, however, they assume a proper form, and many of them survive. In Egypt, and some other places, where the women suffer little pain in parturition, and where they bear many children with ease, those even at the end of eight months are capable of living, even although they should be monstrous; but in such places children born in the eighth month may survive and be brought up. In Greece, however, few of them survive, and most of them perish; and people suspect that if any of them survive, the exact period of conception must have been mistaken by the mother.
6. Women suffer most in the fourth and eighth month, and if the fœtus dies in the fourth or eighth month, they usually die also; so that not only children born in the eighth month often perish, but their mothers also perish with them. In the same way, the period of conception probably is mistaken by those who have been pregnant more than eleven months; for in these cases the beginning of the conception escapes the notice of females, for frequently after the uterus has been distended with flatulence, women have copulated and conceived, and supposed that the former condition in which they observed the usual symptoms, was the commencement of gestation.
CHAPTER V.
1. The human subject also differs from other animals, as to the number of the perfect offspring produced at a birth. For the human subject differs both from animals which produce but one, and those which produce many; for, generally speaking, and, in most cases, women have but one child at a time, though cases of twins occur frequently, and in many places, as in Egypt, three or four at a birth have been known in some particular places, as I have observed before. Five at a birth are the most that have been produced. This has been observed to take place in many cases, but in one case only have twenty been produced at four births, for five were born each time, and many of them were reared. In other animals, if the twins are male and female, there is no more difficulty in rearing and preserving them, than if they were both of the same sex. In the human subject there are few cases of twins surviving, when one was male and the other female.
2. The human female and the mare copulate after conception more than any other creatures, for all other females, when they have conceived, fly from the males, except those which, like the hare, become pregnant a second time during gestation. But the mare, having once conceived, does not form a second fœtus, but generally produces a single foal. In the human subject it happens sometimes, though rarely. Those which are conceived a long while afterwards never come to perfection, but, from the pain which they cause, destroy the original fœtus; and a case has occurred in which twelve imperfect embryos have been produced at one time. If the second conception take place soon after the first, they bear and produce the fœtus, as if it were a twin. This, they say, was the case with Iphicles and Hercules.
3. The possibility of the case is manifest, for an adulteress has been known to produce one child like her husband, and another like her paramour; and a case has occurred of a woman having conceived twins, and then conceived a third child upon them; and when the proper time came, the twins were born perfect, the other was only a fœtus of five months old, which died immediately: and in another case, a woman produced, first of all, a fœtus of seven months old, and then twins, perfectly developed; the former perished, but the latter survived. And some women have conceived at the same time as they miscarried, and have ejected one fœtus while they bore the other. In most females, who have cohabited after the eighth month after conception, the child has been born filled with a shining mucous-like substance, and has often appeared full of the food which has been eaten by the mother; and if she has fed upon food more than usually salt, the child has been born without nails.
CHAPTER VI.
1. The milk that is produced before the seventh month is useless; but as soon as the child is alive the milk becomes good. At first it is salt, like that of sheep. Most women during pregnancy are affected by wine, and if they drink it they become faint and feeble. The beginning and the ending of the reproductive power in both sexes is marked in the male by the emission of the semen, in the female by the catamenia.
They are not, however, fertile when these first occur, nor while they are still small and weak. The period of the commencement of these signs has been mentioned. In women the catamenia usually cease at forty; but if they pass over this age, they go on to fifty; and some have even produced children at that period, but none later than this period.
2. The reproductive function in men usually continues active till they are sixty years old; if they pass beyond this period, till they are seventy; and some men have had children at seventy years old. It frequently happens that, when marriages are unfruitful, both men and women become pregnant, if the marriage is dissolved and they marry again. The same thing takes place respecting the birth of male and female children. For sometimes only children of one sex are produced by a marriage; and if this is dissolved, and the parents marry again, children of the other sex are produced. These things also vary with the age of the parents; for some when young have female children, and when older males, though the contrary sometimes takes place.
3. The same is the case with the whole of the reproductive function.
For some persons have no children when they are young, but have them afterwards; others have children at first, but none afterwards; and there are some women who conceive with difficulty, but when they have conceived bear children; others conceive easily, but the fœtus never comes to maturity. There are also both men and women who only produce children of one sex, as the story goes of Hercules, who had but one daughter in seventy-two children. Those who have been barren, and either after great care, or from any other cause, at last conceive, more frequently bear a daughter than a son. It often happens also that men who have engendered become impotent, and subsequently return to their former condition.
4. Maimed parents produce maimed children; and so also lame and blind parents produce lame and blind children; and, on the whole, children are often born with anything contrary to nature, or any mark which their parents may have, such as tumours and wounds. Such marks have often been handed down for three generations; as if a person had a mark on their arm which was not seen in the son, but the grandson exhibited a dark confused spot on the same place. The circumstances, however, are rare; and sound children are generally produced from lame parents; nor is there any complete certainty in these matters; and children resemble their parents or their grandparents, and sometimes they resemble neither. This is handed down for many generations; as in Sicily, a woman cohabited with an Ethiopian, her daughter was not black, but her daughter's child was so.
5. For the most part the girls resemble their mother, and the boys their father; though the contrary is often the case, and the females resemble their father, and the males their mother, and the different parts of the body resemble either parents. Twins have sometimes no resemblance to each other, but they are generally much alike; and one woman cohabited with a man, and conceived seven days after parturition, when she bore a child as like her former as if they had been twins.
Some women, as well as other creatures, produce young resembling themselves, others bear those which resemble the male, as the horse called Dicæa in Pharsalia.
CHAPTER VII.
1. The seminal fluid in its emission is preceded by wind. The manner of its emission exhibits this; for nothing is expelled to a great distance without pneumatic force. If the seminal fluid is taken up by the uterus and retained there, it becomes inclosed in a membrane. For if it is expelled before it becomes articulated, it appears like an ovum inclosed in a membrane, but without any shell, and the membrane is full of veins. All animals, whether furnished with fins, feet, or wings, whether viviparous or oviparous, are produced in the same manner, except that the umbilicus in viviparous animals is turned towards the uterus, and in others to the ovum; and in some cases both ways, as in a certain kind of fish. Some of them are surrounded by a membrane, others by a chorion. First of all, the fœtus is contained within the last envelope. Then there is another membrane over this, which is in part united to the matrix and is partly separate, and contains water.
Between these is a watery or sanguineous fluid, which in women is called prophorus.
2. All animals that have a navel increase by the navel; and in those which have acetabula the navel is united to the acetabulum; and in those which have a smooth uterus the navel is united to the uterus upon a vein. The position of all quadrupeds in the uterus is stretched out; that of fishes is on the side; bipeds, as birds, are folded together.
The human fœtus lies folded up with its nose between its knees and its eyes upon them, and its ears turned outwards. All animals are alike in having the head placed upwards at first. As they grow, the head turns round, and the birth of all animals is naturally with the head forwards: for even in those that are folded together the presentation of the feet is unnatural. The embryo of quadrupeds contains excrementitious matter, as soon as it is matured, both fluid and solid. The latter is contained in the extreme parts of the intestine, the former in the bladder.
3. If animals have acetabula in the uterus, these acetabula always become smaller as the fœtus grows, and at last disappear. The umbilical cord is a covering for veins, of which the origin is in the uterus.
In those creatures which have acetabula it originates in them; in those that have not acetabula it originates in the vein. In the larger animals, such as the fœtus of oxen, there are four veins; in smaller animals, two; in very small animals, as in birds, there is but one.
Two veins reach the fœtus through the liver, from that part called the gates of the liver, towards the great vein; and two go to the aorta, where it is divided into two parts; and there are membranes round each pair of veins, and the umbilical cord surrounds these membranes like a covering. As the fœtus increases, these veins diminish. The embryo, as it grows, advances into the viscera, where its movements are manifest.
Sometimes it remains rolled up near the pudendum.
CHAPTER VIII.
1. When the pains of parturition come on, they extend to many and various parts of the body, but especially to one or other of the thighs. Those who suffer most in the bowels are delivered most rapidly; those who suffer much in the loins are delivered with difficulty; those whose pain lies in the subumbilical region, more quickly. If the child is a male, a liquid, serum-like discharge, of a pale yellow colour, precedes; if a female, this discharge is sanguineous, but still fluid.
Some women have neither during the period of parturition.
2. In other animals parturition is not painful, and it is evident that they suffer but moderately in the pains of labour. In women the pains of parturition are more violent, especially in those that are inactive or that are not well made in their sides, and are unable to hold their breath. They also suffer more in parturition, if they breathe in the meantime, compelled by the necessity of respiration. At first a fluid escapes when the fœtus comes to the birth, and the membranes are ruptured; after this, the embryo is excluded, the uterus being turned, and the uterus being turned inside-out.
CHAPTER IX.
1. The division of the umbilical cord often requires the careful attention of the midwife; for by skilfulness she may not only assist in difficult labours, but should attend carefully to the circumstances, and apply the ligature to the umbilical cord of the child; for if the secundines fall out with the child, the umbilical cord must be bound with a ligature of worsted, and cut above the ligature, and where it is bound it joins together, and that which is joined with it falls off. If the ligature becomes loose, the child dies from loss of blood. If the secundines do not come out at once, while they remain within, and the child is outside, the umbilical cord must be tied and divided.
2. Frequently the child, if weak, has appeared as if born dead, until the umbilical cord was tied, for the blood flowed from the child to the navel and the surrounding parts; but some skilful midwife being present, by pressure on the navel from within has revived the child, just as if it had been filled with blood from the first. It has been already observed, that all animals are naturally born with the head forwards. Children also have their hands pressed down against their sides. As soon as they are born they begin to cry and bring their hands to their mouth. They emit excrements, some immediately, others very soon, but all in the course of a day. This excrementitious matter is very abundant, considering the size of the child. Women call it the meconium. Its colour is like that of blood, and it is black and pitch-like. Afterwards it becomes milky, for the child immediately draws the breast. The child never cries before it is entirely in the world, not even though its head is protruded in difficult cases, while the body is within the uterus.
3. Those women in whom a flooding has preceded the period of delivery are delivered with more difficulty, and if the purifications are small after parturition, and only as much as they are at first, and do not continue for more than forty days, such women are stronger, and more ready for conception. After children are born, for forty days they neither laugh nor weep when awake, but sometimes do both in their sleep; nor do they usually feel when they are tickled, but they sleep the greater part of their time. As they grow, the period of wakefulness continually increases; and it is evident that they dream, but it is some time before they remember their imaginations. There is no difference in the bones of other animals, but they are all born perfect. In children the bone called bregma is soft, and does not become strong for some time. Some animals are born with teeth, but children begin to cut their teeth in the seventh month. The front teeth naturally appear first, sometimes the upper teeth and sometimes the under. Children cut their teeth more easily if their nurses have warmer milk.
CHAPTER X.
After parturition and purification women become full of milk; and in some it not only flows through the nipples but through other parts of the breast, and sometimes from the cheeks; and if this fluid is not matured nor secreted, but remains full, hard knots are formed, which remain for a long time; for every part of the breast is so spongy that, if a hair is swallowed with the drink, pain ensues in the breasts, until it either escapes spontaneously with the milk, or is sucked out, this is called τριχιᾷν. They continue to have milk until they conceive again. It then ceases, and is quenched in other creatures as well as in the human subject. The catamenia seldom take place while milk is secreted, though this sometimes occurs in women while nursing. On the whole, an effusion of fluid seldom takes place from many parts of the body at the same time, and those that have hæmorrhoids have usually less purification. In some it takes place through ixiæ (varices), and is secreted from the loins before it reaches the uterus; and those who vomit blood when the purification is suppressed suffer no harm.
CHAPTER XI.
Children are very subject to spasms, and especially those that are in a good condition and have abundance of rich milk, or whose nurses are fat. Wine is injurious in this complaint, and dark-coloured wines more so than those that are pale, and food that is not fluid, and windy aliments, and stoppage in the bowels. Children with this complaint generally die before the seventh day: wherefore also this day has received a name, as if it gave some hope of the recovery of the child.
Children suffer most at the full moon. Children are in great danger when the spasms originate in the back, especially if they are advancing in age.[215] [215] The seventh book ends very abruptly, and hence it has been thought that what is now called the tenth book, in which the subject of reproduction is continued, would have its proper place here, as a continuation of the seventh. Whether a portion of the genuine work of Aristotle has been lost which would have completed the subject is another question; but there can be little doubt that the tenth book, in the form in which we have it, is no genuine work of Aristotle; some of the opinions are contrary to those which he has expressed, and the whole style and language is different from that of Aristotle. Schneider therefore has placed the tenth book at the end of the work, that he may neither entirely exclude that which in former times was considered a portion of Aristotle's treatise on Animals, nor yet allow a fictitious book to interrupt the genuine writings of his Author.
BOOK THE EIGHTH.
CHAPTER I.
1. The nature of animals and their mode of reproduction has now been described. Their actions and mode of life also differ according to their disposition and their food. For almost all animals present traces of their moral dispositions, though these distinctions are most remarkable in man. For most of them, as we remarked, when speaking of their various parts, appear to exhibit gentleness or ferocity, mildness or cruelty, courage or cowardice, fear or boldness, violence or cunning; and many of them exhibit something like a rational consciousness, as we remarked in speaking of their parts. For they differ from man, and man from the other animals, in a greater or less degree; for some of these traits are exhibited strongly in man, and others in other animals.
2. Others differ in proportion. For as men exhibit art, wisdom, and intelligence, animals possess, by way of compensation, some other physical power. This is most conspicuous in the examination of infants, for in them we see, as it were, the vestiges and seeds of their future disposition; nor does their soul at this period differ in any respect from that of an animal; so that it is not unreasonable for animals to present the same, or similar, or analogous appearances. Nature passes so gradually from inanimate to animate things, that from their continuity their boundary and the mean between them is indistinct. The race of plants succeeds immediately that of inanimate objects; and these differ from each other in the proportion of life in which they participate; for, compared with other bodies, plants appear to possess life, though, when compared with animals, they appear inanimate.
3. The change from plants to animals, however, is gradual, as I before observed. For a person might question to which of these classes some marine objects belong; for many of them are attached to the rock, and perish as soon as they are separated from it. The pinnæ are attached to the rocks, the solens cannot live after they are taken away from their localities; and, on the whole, all the testacea resemble plants, if we compare them with locomotive animals. Some of them appear to have no sensation; in others it is very dull. The body of some of them is naturally fleshy, as of those which are called tethya; and the acalephe and the sponge entirely resemble plants; the progress is always gradual by which one appears to have more life and motion than another.
4. In the vital actions also we may observe the same manner. For vegetables which are produced from seed appear to have no other work beyond reproduction; nor do some animals appear to have any other object in their existence. This object then is common to them all; but as sensation advances, their manner of life differs in their having pleasure in sexual intercourse, in their mode of parturition and rearing their young. Some of them, like plants, simply accomplish their peculiar mode of reproduction at an appointed season, and others are diligent in rearing their young; but as soon as this is accomplished they separate from them, and have no farther communication; but those that are more intelligent, and possess more memory, use their offspring in a more civilized manner.
5. The work of reproduction is one part of their life, the work of procuring food forms another. These two occupy their labour and their life. Their food differs in the substances of which it consists, and all the natural increase of the body is derived from food. That which is natural is pleasant, and all animals follow that which is pleasant to their nature.
CHAPTER II.
1. Animals are divided according to the localities which they inhabit; for some animals are terrestrial, others are aquatic. They also admit of a ternary division, those that breathe air and those that breathe water, one of these classes is terrestrial, the other is aquatic; the third class does not breathe either air or water, but they are adapted by nature to receive refreshment from each of these elements; and some of these are called terrestrial, others are aquatic, though they neither breathe air or water; and there are other animals which procure their food and make their abode in either of these elements. For many that breathe air, and produce their young upon the land, procure their food from the water, where they generally make their abode; and these are the only animals which appear to be doubtful, for they may be arranged either as terrestrial or aquatic animals.
2. Of those that breathe water, none have feet or wings, nor seek their food on land; but many of those that are terrestrial, and breathe air, do so; some of them so much so, that they cannot live when separated from the water, as those which are called marine turtles, and crocodiles, and hippopotami, and seals, and some of the smaller creatures, as the water tortoise and the frog tribe; for all these are suffocated if their respiration is suspended for any length of time.
They produce their young and rear them on dry land; others do so near the dry land, while they reside in the water.
3. Of all animals the most remarkable in this particular is the dolphin, and some other aquatic animals and cetacea which are of this habit, as the whale and others which have a blowhole; for it is not easy to arrange them either with aquatic or terrestrial animals, if we consider animals that breathe air as terrestrial, and those that breathe water as aquatics, for they partake of the characters of both classes; for they receive the sea and eject it through their blowhole, and air through their lungs, for they have this part, and breathe through it. And the dolphin, when captured in nets, is often suffocated, from the impossibility of breathing. It will live for a long while out of water, snoring and groaning like other breathing animals. It sleeps with its snout above the water, in order that it may breathe through it.
4. It is thus impossible to arrange it under both of these contrary divisions, but it would appear that the aquatic animals must be further subdivided; for they breathe and eject water for the same reason as others breathe air, for the sake of coolness. Other animals do this for the sake of food; for those animals which obtain their food in the water, must also, at the same time, swallow some of the fluid, and have an organ by which they can eject it. Those creatures which use water instead of air for breathing have gills; those that use it for food have a blowhole. These creatures are sanguineous. The nature of the malacia and malacostraca is the same; for these swallow water for food.
5. Those animals which breathe air, but live in the water, and those which breathe water, and have gills, but go out upon dry land and take their food there, belong to two divisions of aquatic animals. This last division is represented by a single animal called the cordylus (water newt); for this animal has no lungs, but gills; and it goes on dry land to procure its food. It has four feet, so that it appears natural that it should walk. In all these animals nature appears to be, as it were, turned aside, and some of the males appear to be females, and the females have a male appearance; for animals which have but small diversity in particular parts, exhibit great variations in the whole body.
6. This is evident in castrated animals; for if a small portion only of the body is destroyed, the animal becomes a female; so that it is plain that if a very minute portion in the original composition of an animal becomes changed, if that portion belongs to the origin of the species, it might become either male or female; or, if taken away altogether, the animal might be neuter. And so, either way, it might become a land or aquatic animal, if only a small change took place...it happens that some become terrestrial and others aquatic animals, and some are not amphibious which others are, because in their original generation they received some kind of substance which they use for food. For that which is natural is agreeable to every animal, as I have said before.
CHAPTER III.
1. When animals are divided in three ways into aquatic and land animals, because they either breathe air or water, or from the composition of their bodies; or, in the third place, from their food, their manner of life will be found to agree with these divisions. For some follow both the composition of their bodies and the nature of their food, and their respiration of either water or air. Others only agree with their composition and food.
2. The testacea which are immoveable live by a fluid which percolates through the dense parts of the sea, and being digested because it is lighter than the sea water, thus returns to its original nature.
That this fluid exists in the sea, and is capable of infiltration is manifest, and may be proved by experiment; for if anyone will make a thin waxen vessel, and sink it empty in the sea, in a night and a day, it may be taken up full of water, which is drinkable.
3. The acalephe (actinia) feeds upon any small fish which may fall in its way. Its mouth is placed in the centre of its body. This organ is conspicuous in the larger individuals: like the oyster, it has a passage for the exclusion of its food, which is placed above. The acalephe appears to resemble the internal part of the oyster, and it makes use of the rock, as the oyster does of its shell. (The patella also is free, and wanders about in search of food.)
4. Among the locomotive testacea, some are carnivorous, and live on small fish, as the purpura, for this creature is carnivorous, it is therefore caught with a bait of flesh: others live upon marine plants.
The marine turtles live upon shell-fish, for which purpose they have a very powerful mouth; for if any of them take a stone or anything else, they break and eat it. This animal leaves the water and eats grass.
They often suffer and perish, when they are dried up as they float on the surface, for they are not able to dive readily.
5. The malacostraca are of the same nature, for they eat everything; they feed upon stones and mud, seaweeds and dung, as the rock crabs, and are also carnivorous. The spiny lobsters also overcome large fishes, and a kind of retribution awaits them in turn, for the polypus prevails over the lobster, for they are not inconvenienced by the shell of the lobster, so that if the lobsters perceive them in the same net with them, they die from fear. The spiny lobsters overcome the congers, for their roughness prevents them from falling off. The congers devour the polypi which cannot adhere to them on account of the smoothness of their surface; all the malacia are carnivorous.
6. The spiny lobsters also live on small fish, which they hunt for in their holes, for they are produced in such parts of the sea as are rough and stony, and in those places make their habitations; whatever they capture, they bring to their mouth with their double claw, as the crabs do. When not frightened they naturally walk forwards, hanging their horns down at their sides. When alarmed they retreat backwards, and extend their horns to a great distance. They fight with each other like rams with their horns, raising them and striking each other. They are often seen in numbers as if they were gregarious.
7. The malacostraca lead this kind of life. Among the malacia the teuthis and sepia prevail over the large fish. The polypus generally collects shells which it empties of their contents and feeds upon them, so that those who seek for them find their holes by the shells that are scattered about. The report that they eat each other is a mistake; but some have the tentacula eaten off by the congers.
CHAPTER IV.
1. All fish at the season of oviposition live upon ova; in the rest of their food they are not all so well agreed, for some of them are only carnivorous, as the selachos, conger, channa, thynnus, labrax, sinodon, amia, orphus, and muræna; the trigla lives upon fuci, shell-fish, and mud; it is also carnivorous. The cephalus lives on mud, the dascillus on mud and dung. The scarus and melanurus on sea-weed, the salpa on dung and fuci, it will also eat the plant called horehound; it is the only fish that can be caught with the gourd.
2. All fish, except the cestreus, eat one another, especially the congers. The cephalus and the cestreus alone are not carnivorous. This is a proof of it. They are never captured with anything of the kind in their stomach, nor are they captured with a bait made of flesh, but with bread; the cestreus is always fed upon sea-weed and sand. One kind of cephalus which some persons call chelone lives near the land, another is called peræas. This last feeds upon nothing but its own mucus, for which reason it is always very poor. The cephalus lives upon mud, wherefore they are heavy and slimy. They certainly never eat fish, on account of their dwelling in mud; they often emerge in order to wash themselves from the slime. Neither will any creature eat their ova, so that they increase rapidly, and when they increase they are devoured by other fish, and especially by the acharnus.
3. The cestreus (mullet) is the most greedy and insatiable of fish, so that its abdomen is distended, and it is not good for food unless it is poor. When alarmed it hides its head, as if its whole body were thus concealed; the sinodon also is carnivorous, and eats the malacia. This fish and the channa often eject their stomachs as they pursue small fish, for their stomach is near the mouth, and they have no œsophagus.
Some are simply carnivorous, as the dolphin, sinodon, chrysophrys, the selache and malacia; others, as the phycis, cobius, and the rock-fish, principally feed upon mud and fuci, and bryum, and what is called caulion, and any matter which may be produced in the sea. The phycis eats no other flesh than that of the shrimps. They also frequently eat each other, as I before remarked, and the greater devour the less. It is a proof that they are carnivorous, that they are captured with bait made of flesh.
4. The amia, tunny, and labrax generally eat flesh, though they also eat sea-weed. The sargus feeds after the trigla when the last has buried itself in the mud and departed, for it has the power of burying itself, then the sargus comes and feeds and prevents all those that are weaker than itself from approaching. The fish called scarus is the only one which appears to ruminate like quadrupeds. Other fish appear to hunt the smaller ones with their mouths towards them, in this way they naturally swim; but the selachea, dolphins and cetacea throw themselves on their back to capture their prey, for their mouth is placed below them, for this reason the smaller ones escape, or if not they would soon be reduced in number; for the swiftness of the dolphin and its capacity for food appear incredible.
5. A few eels in some places are fed upon mud, and any kind of food which may be cast into the water, but generally they live upon fresh water, and those who rear eels take care that the water which flows off and on upon the shallows in which they live may be clear, where they make the eel preserves. For they are soon suffocated if the water is not clean, their gills being very small. For this reason those who seek for them disturb the water. In the Strymon they are taken about the time of the rising of the Pleiades. For the water is disturbed at this season by the mud which is stirred up by contrary winds, otherwise it is useless to attempt to obtain them. When dead, eels do not rise and float on the surface, like other fishes, for their stomach is small; a few of them are fat, but this is not usually the case.
6. When taken out of the water, they will live five or six days; if the wind is in the north they will live longer than if it is in the south. If they are removed from the ponds to the eel preserves during the summer they perish, but not if removed in the winter; neither will they bear violent changes, for if they are taken and plunged into cold water, they often perish in great numbers. They are suffocated also if kept in a small quantity of water. This takes place also in other fish, which are suffocated if kept in a small quantity of water which is never changed, like animals which breathe air when enclosed in a small quantity of air. Some eels live seven or eight years. Fresh-water fish make use of food, and devour each other, as well as plants and roots, or anything else that they can find in the mud; they generally feed in the night, and during the day dwell in deep holes. This is the nature of the food of fish.
CHAPTER V.
1. All birds with crooked claws are carnivorous, nor are they able to eat corn even when put in their mouths. All the eagles belong to this class and the kites, and both the hawks, the pigeon hawk namely, and the sparrow hawk. These differ in size from each other, and so does the triorches. This bird is as large as the kite, and is visible at all seasons of the year; the osprey and vulture also belong to this class.
The osprey is as large as the eagle, and ash-coloured. There are two kinds of vultures, one small and whitish, the other large and cinereous.
2. Some of the night birds also have crooked claws, as the nycticorax, owl, and bryas. The bryas resembles an owl in appearance, but it is as large as an eagle; the eleos, ægolius, and scops also belong to this