accelerating or retarding the exit of the air, he can imitate different voices, and induces his auditors to a belief that the interlocutors of a dialogue, which is kept up by himself alone, are placed at different distances; and this illusion is the more complete in proportion to the perfection of his peculiar talent. No man possesses, to such a degree as Mr. FitzJames, the art of deceiving persons who are least liable to delusion; he can carry his execution to five or six different tones, pass rapidly from one to another, as he does when representing an animated dispute in the midst of a popular assembly." On the subject of the Generative Functions, we have very little to add to what the reader will find under the articles ANATOMY, COMPARATIVE ANATOMY, and FŒTUS. The bodies of the male and female present very obvious differences in appearance and character, which have been ascribed to the influence of the generative organs upon the constitution. The removal of the testes in the male prevents those changes, in the beard and voice, at the time of puberty, which would otherwise occur: and eunuchs even approach in other respects to the female character, as in the breadth and projection of the hips. Again, in some remarkable cases, where the organs of the female have been wanting, or malformed, similar effects have taken place in the constitution; so that there is some reason for saying with Von Helmont, propter solum uterum mulier est, id quod est. Hermaprodism, or the union of both sexes in the same individual, is impossible in man and the warm-blooded animals. All the supposed hermaphrodites hitherto examined were mal-formed beings, whose male organs were imperfect, or the female apparatus too prominent, so as to render the sex doubtful. No one has shown himself capable of impregnating his own person, so as to produce a being like himself; indeed, in most instances they were incapable of assisting in reproduction, as an imperfection of the organs employed for that purpose condemned them to sterility. Man presents a peculiarity, in not being subject to the influence of the seasons in the exercise of his generative functions; while other animals cohabit at fixed periods and certain times of the year, and afterwards seem to forget the pleasures of love, to satisfy other wants. Conception. Physiologists have not hitherto succeeded in explaining the me chanism of that elongated and distended state of the penis, occurring under the irritation of the sexual passion, which adapts the organ to the performance of its natural functions. The obvious circumstances are, that the cells of the corpus spongiosum urethra, and corpora cavernosa penis, are distended to the utmost with blood, poured into them from the arteries much faster than it can be, or at least is, returned by the veins. The irritation which affects the penis, extends to the internal parts. The secretion of the testes becomes more active, and these bodies are drawn up towards the abdomen; the vesiculæ seminales, and the ducts of the prostate, also pour out their contents into the urethra. The semen is a mixed fluid, derived from the three sources just mentioned; but the smallest part probably comes from the testes. The most remarkable circumstance in this fluid is, that it contains numerous microscopic animalcula, with a round head and slender tail, moving about with rapidity. This prolific liquor is expelled from the penis by a spasmodic action of the accelerator urinæ muscle; the whole body seems to participate in the same convulsive state, and the instant of ejacu lation is marked by an orgasm through every part. It seems that nature has forgotten, for the moment, every other function, and is totally occupied in collecting her powers, and directing them towards the same point. Hence an univulsion, and hence the old observation, versal languor follows this general conomne animal post coitum triste est. The seminal liquor, thus propelled is supposed to pass through the uterus into the generative organs of the female, and fallopian tubes, and to come into ac tual contact with the ovaria. The closeness of the mouth, and indeed of the whole cavity of the uterus, together with tube, especially at its origin in the uterus, the very small calibre of the fallopian (where it will only admit a bristle) are difficulties in the way of this explanation, which have led to the opinion, that the semen itself does not penetrate into the uterus, but that an exhalation, or aura seminalis, comes into contact with the germs, and is sufficient for their fecundation. This is opposed by the experi ments of Spallanzani and others, in which the ova of frogs were readily impregnated by contact of the seminal fluid, but were not at all affected by the vapour or aura. The attachment of the fimbriæ of the tube to the ovarium, which experiment has shewn to occur during coition, establishes an uninterrupted canal from the uterus to the ovarium, and prevents the semen from becoming diffused in the abdomen. The germ of the future being preexists in the ovarium, where it is formed by a peculiar action of the part, in short, by a true secretion. This germ, in its original state, is a small vesicle of fluid, first noticed by De Graaf, whence the term of ovula Graafiana applied to their appearance in the virgin ovary. Here we do not mean to countenance those doctrines of evolution which suppose that generation only developes germs that have existed from the beginning of the world. We suppose, that the ova produced by the elaboration of blood, carried to the ovaria by the spermatic vessels, contain the rudiments of the new beings. But the germs in that state are inert, and require that the seminal spirit should be employed to rouse them from their inactivity. In birds and reptiles the formation of the germ by the female is incontestible; it is not quite so obvious in the class of mammalia; but we infer it here from analogy, and also from the experiment of Mr. Hunter, in which the removal of one ovarium from a sow diminished in a remarkable degree the number of young produced. Fetal Existence. This is purely vegetative. The fœtus receives the fluids brought by the vessels of the mother "to the placenta for its growth and nourishment. It may be considered as a new organ, the produce of conception, participating in the general life, but possessing a vitality peculiar to itself, and, to a certain degree, independent of that of the mother. To say that it is asleep is erroneous; for not only are the organs of sense and voluntary motion in a state of perfect repose, but also several of the assimilating functions are totally unemployed, as digestion, respiration, and the generality of the secretions. The fœtus, however, performs spontaneous motions, which accoucheurs enumerate among the signs of pregnancy. It is nourished, like every other organ, by appropriating to itself whatever is found in the blood, brought by the vessels of the uterus proper for its purpose; and the interception of this fluid by the ligature, or compression of the umbilical chord, occasions death. Suckling. The close sympathy between the uterus and breasts is so obvious, as to attract the notice of every observer. Both these organs are developed at the same period of life, and cease together to perform their functions, when the female becomes incapable of contributing towards the continuation of the species. The breasts increase in size during preg nancy, but are never more swelled than after parturition. The infant applies its mouth to the nipple, and sucks; i. e. forms a vacuum by inspiring, in consequence of which the atmospheric pressure forces the milk through the lactiferous tubes into its mouth. The nipple experiences a vascular turgescence, or kind of erection; which also affects the excretory tubes of the mammary gland, so as to cause them sometimes to expel the fluid to some distance by jets. The structure of the breast is explained under the article MAMMARY GLAND, and the composition of their secretion under MILK. Ages, Temperaments, &c. Having thus gone through the animal economy, according to its distribution into particular functions, we shall just contemplate man in a general view, passing through the whole course of his existence, and note the principal epochas of his life, from its commencement to the termination in death. The first perceptible traces of the fœtus occur about three months after conception. It is then animated by a very slight kind of vegetable life, and possesses true blood, and motion of the heart, about the fourth week. The latter, as observed in the chicken, has been named, from the time of Aristotle, punctum saliens. The formation of bones commences about the seventh or eighth week. The earthy particles are first deposited in nuclei in the clavicles, ribs, vertebræ, larger cylindrical bones of the extremities, lower jaw, and face; a very delicate net-work is also seen in some of the bones of the cranium. As a general observation, it may be affirmed that the growth of the embryo, as well as of the child, both before and after birth, is more rapid in proportion as it is younger. About the middle of pregnancy, the operation of some vital functions is discerned: the secretion of fat and bile commences. At a more advanced period of utero-gestation, the scalp is covered with a short and delicate hair: the nails are formed; the membrana pupillaris destroyed; the external ear becomes firmer and more elastic; and the testes descend. Besides the important changes in the whole economy which follow parturition, there are certain alterations in the external habit of the body. The down which covers the face at birth disappears; the rugæ of the skin are obliterated; the anus becomes hidden between the buttocks, which are now gradually formed. The infant gradually brings into action the faculties of the mind. It perceives and attends to external objects, remembers, desires, &c. It smiles in the second month, and seems to dream at no great length of time after birth. The organs of sense become more complete in their formation. The bones of the skull become stronger, and the fontanelles are diminished. Dentition commences about the eighth month. The infant may then be weaned, as his teeth enable him to commence the use of more solid food. About the end of the first year he learns to stand on his feet, and to assume the erect posture, that most distinguishing attribute of the human body. When it has now been removed from the breast, and learned the use of the lower limbs, its powers and independence increase daily, and receive a vast accession from the developement of another peculiar privilege of the human subject, the enjoyment of speech; by which the tongue, under the direction of the mind, pronounces those ideas which are now become familiar. At the seventh year the twenty milk teeth begin to fall out, and are succeeded in a gradual progress during the following years by the thirty-two permanent teeth. At this time the memory excels all the other faculties of the mind; whereas about the fifteenth year the powers of imagination begin to prevail. This is the time of puberty, in which the human subject is gradually prepared, by various important changes, for the exercise of the sexual functions. The breasts enlarge in the female, the chin becomes covered with hair in the male, and other similar signs of puberty are noticed in both sexes. The menstrual discharge commences in the softer sex; and this important era in the economy of the female is marked by an increased expression in the eyes, and redness of the lips, and more manifest sensible qualities in the matter of perspiration. The seminal secretion becomes active in the male, attended with an increase of the beard, and a deepening of the voice, consequent on a remarkable developement of the larynx. The internal and spontaneous calls of nature now rouse the sexual instinct, for the exertion of which both sexes are prepared. No definite and precise period can be assigned for the changes which constitute puberty: it varies according to climate and temperament. It is more early in the female than in the male; but in this climate girls may be said to attain it at the age of fourteen or fifteen, and men at seventeen or eighteen. Soon after these periods, the growth of the body is completed; the stature of which varies much in different races, not to mention its varieties in individuals and families. The epiphyses, which have hitherto been distinct from the body of the bone, are now completely consolidated with it. Virility, Manhood, or Adult Age begins from the twenty-first to the twenty-fifth year. If the increase of the body in height have ceased at this time, it grows in other dimensions. The organs become firm and consistent; their functions are per formed with vigour; the intellectual and moral faculties are perfected; and the dominion of the judgment succeeds that of the imagination. This period, which is called that of mature age, extends to the fiftieth or fifty-fifty year in men, but not much beyond the forty-fifth in women, in whom it begins earlier. During this long interval men enjoy all the plenitude of their existence. Temperaments. As the characters of the human species are now fixed with stability, we may sketch the differences which mark individuals. Health, in the expla nation of which all physiology is concerned, consists in such a harmony and equilibrium of the material fabric of the body, and of its animating powers, as is necessary for the performance of the various functions. It requires, therefore, fluids rightly prepared; solids duly formed from these; the latter thoroughly animated by their vital powers; and, lastly, 2 sound mind in this healthy body. These four principles are constantly acting and reacting in the human body. The fluids act as stimuli on the solids, which possess vital powers, enabling them to receive those stimuli, and to react. The connection of the mind and body is not discerned merely in the influence of the will, in what physiologists call voluntary actions; since the affections of the body clearly act on the mind in many other ways than through the medium of sensual perceptions. The infinitely varied modifications, which the four principles admit of, shew immediately with what latitude our notions concerning health should be formed. Hence arises the distinction of temperaments; that is, the dif ferent manner in which the living solid is affected by stimuli, particularly of the mental class, the different aptitude for such impressions, and the greater or less facility with which these stimuli may themselves be excited. There is such great variety of degrees and combinations of temperaments, that a wide field is open for those who wish to employ themselves in dividing and arranging them, The common division is sufficient for our purpose; it comprehends the sanguine ous, which is very easily but slightly affected by stimuli; the choleric, which is easily and strongly excited; the melancholic, which is slowly but deeply moved; and the phlegmatic, which is the slowest of all in admitting the impressions of exciting causes. Together with these distinctions, there are numerous differences of bodily formation, of diversity in the proportion and connection of parts, as well as in the energy relative to certain organs, accompanying each temperament, which cannot be particularized here, without entering too much into detail. Each individual has a particular manner of being, which distinguishes his temperament from that of every other, to which, notwithstanding it may bear a very strong resemblance. These individual temperaments, the knowledge of which is of no small importance in the practice of physic, are called idio-syncra sies. There are many both pre-disposing and Occasional causes, which have an operation in producing this diversity of temperaments; as hereditary disposition, habit of body, climate, diet, religion, culture, luxury, &c. For the account of the various races of mankind, see the article MAN. Advanced Age and Decay. Cessation of the menses in women, which is occasionally accompanied by the production of a beard; an indisposition to venery in the male sex; and, in both, a peculiar dryness, and sensible decrease in the vital powers, are the signs of approaching, old age. The body now diminishes and loses the power it had acquired; the de crease following the same progression as the growth, and occupying about the same space of time, when no accident hastens the approach of death. The whole volume of the body diminishes, the skin wrinkles, particularly in the forehead and face; the hair turns grey, and organic action becomes languid. The decay of the body is evidenced by an increasing dulness both of the external and internal senses, necessity of longer sleep, and general torpor of all the functions. The hair grows white, and falls off, the teeth drop from their sockets, the cartilages ossify, all the organs become hard, and the fibres more dry and contracted. The head is no longer supported by the neck, nor can the legs sustain the trunk; nay, the bones themselves, the foundations of the machine, partake of the general decay. On these phenomena we may observe, that the animal or exterior life ceases first, the senses fail in succession, and then the functions of the brain cease. The cessation of the locomotive and vocal powers follows as a necessary consequence. Here, then, the old man is dead to all surrounding objects, but his organic life still subsists; so that this state is analogous to that of uterine existence, where the life is nearly of the vegetable kind. Thus, the body gradually dies, life is extinguished by successive shades, and death is only the last term in this succession of degrees. We arrive now at the conclusion of physiology, death without disease, which is the object of all medicine, and the causes of which are necessary and inevitable. It it is no more possible for us to avert the fatal term, than to change the laws of nature. The phenomena of death consist in a coldness of the extremities, gradually mounting to the trunk; dimness of the eye; feeble, slow, and irregular pulse; respiration performed at longer intervals, and terminated at last by a strong expiration. In experiments on animals, a struggle is observed about the heart, and the right ventricle and auricle are found to survive the opposite cavities for a short time. That death has taken place is shown by coldness of the body, combined with rigidity; flaccidity of the cornea, relaxed state of the anus, lividity of the back, and a certain cadaverous odour. When all these circumstances are combined, there will be scarcely any opportunity for remarking the uncertainty of the signs of death. Although the weakness of the thread of life in its early stages, the intemperance of manhood, the power of disease and of accident, exert such destructive effects on the human race, that out of one thousand children born into the world, not more than seventy-eight die as we have now described, without disease; yet on comparing the longevity of man with that of other mammalia, under nearly similar circumstances, we shall be immediately convinced, that, of all the querulous declamations concerning the wretchedness of human life, none is more unjust than the complaint of its short ness. Putrefaction. As soon as life abandons the organs, they become totally influenced by physical laws; and their component parts have a tendency to separate from each other, which is stronger in proportion to the multiplicity of their elements. The entire cessation of life is necessary to this change, for life and putrefaction are two ideas absolutely contradictory of each other. A mild temperature, humidity, and the presence of air, are necessary to putrefaction. Icy coldness, or great heat, prevent it: the former by condensing the parts, the latter by depriving them of moisture. Air is not essential, as bodies will decay in vacuo. All animal substances exhale at first a musty or cadaverous odour, soften, increase in size, become heated, change their colour, turn green, blue, and, lastly, a blackish brown. Several gaseous matters are at the same time disengaged, among which the ammoniacal is the principal, both on account of its quantity, and because animal matter begins to furnish it, from the instant its alteration commences to the period of its complete dissolution. Carbonic acid gas is also disengaged, and forms with the ammoniacal air a fixed salt. Hydrogen, united with phosphorus, sulphur, azote, and carbon, and all things that can result from their respective combinations, are likewise produced. Putrefaction, considered in a philosophical point of view, is only the method employed by nature to return our organs, that are deprived of life, to a more simple composition, in order that their elements may be employed for new creations. (Circulus æterni motus.) Nothing is, therefore, better proved than the metempsychosis of matter; whence we may conclude, that this doctrine, like most of the tenets and fabulous conceptions of antiquity, is only a mysterious veil, dextrous ly interposed between nature and the vulgar by the hand of philosophy. PHYSSOPHORA, in natural history, a genus of the Vermes Mollusca class and order. Generic character: body gelatinous, pendant from the aerial vesicle, with gelatinous sessile members at the sides, and numerous tentacula beneath. There are three species, viz. the hydrostatica, which is of an oval shape; the rosacea, which is orbicular; and the filifor mes, which is lateral, filiform, and pendent. This genus is nearly allied to the MEDUSA tribe, which see. PHYTEUMA, in botany, a genus of the Pentandria Monogynia class and order. Natural order of Campanacea. Campanulacea, Jussieu. Essential character: corolla wheel-shaped, with linear segments, five-parted; stigma bifid, or trifid; capsule two or three-celled, inferior. There are sixteen species. The European sorts of phyteuma have the flowers in a close terminating head; those from the East have them scattered; in all there is a little bracte to each flower. They are all natives of the South of Europe. PHYTOLACCA, in botany, a genus of the Decandria Decagynia class and order. Natural order of Miscellaneæ. Atriplices, Jussieu. Essential character: calyx none; petals five, calycine; berry superior, ten-celled, ten-seeded. There are six species. PHYTOLOGY, a discourse concerning the kinds and virtues of plants. PHYTOTOMA, the plant-cutter, in natural history, a genus of birds of the order Passeres. Generic character; bill conic, straight, and serrated on the edges: nostrils oval; tongue obtuse and short. There are two species. P. rara, or the plant-cutter of Chili, inhabits that country in great plenty, and is about the size of a quail, and feeds on vegetables. These birds take considerable pains to saw off the vegetable as near as possible to the ground, and are extremely injurious in the cultivated lands of the districts which it frequents, and are consequently particularly disliked by the inhabitants. They build in high trees and sequestered situations. They are distinguished by having four toes from the following species, which has only three: P. tridactyla, the Abyssinian plant-cutter. This is of the size of a gros-beak, delights in solitude, and abounds in the wilds of Abyssinia, where it subsists much on the kernels of the almond, breaking the shell with particular ease and dexterity. PICÆ, in natural history, the second |