(flat), to lower; but as it is sometimes desired to bring such a sharp or flat sound to its natural state, another character is used, the (natural). Now, the pupil will observe, that if he place a sharp before Fa, in the scale of Re, it will raise that sound a semitone; and if he place a sharp before the Do, it will also raise it a semi

tone

Λ

By placing the sharp (#) before Fa, he has raised Fa a semitone above what it was before, making the difference between Mi and Fa a tone, the difference between Fa # and Sol being altered as a natural consequence to a semitone, by which the regular order is in this instance obtained. Again, in the same manner with the # before Do, the semitone is transferred from between Si and Do to between Do and Re; thus the semitones fall between the third and fourth (Fa # and Sol) and seventh and eighth (Do # and Re) sounds of the major diatonic scale of Re. In this manner the pupil is taught to place the tones and semitones in their proper positions in all the scales. To practise the divisions of the tones, &c., the hand is again employed, the tips of the fingers representing the flat sounds, and the roots the sharp sounds. The teacher now shows that every minor interval can be made major, and every major interval minor, by placing a sharp or a flat before one of the notes composing it; also that an interval does not change its character when both the notes composing it are made sharp or flat. In practising these intervals, the manual signs representing the tones and semitones are again employed. The various pieces of music to be sung or Solfaed after this, have a more varied character, and consist of rounds, canons, solfeggios, songs, &c., in two, three, or four parts. Some of the airs are written in different keys, to show the effect, and to accustom the pupils to transposition from one key to another. The distinction between the diatonic and the chromatic semitone is next explained; the former being formed by two notes a semitone apart, standing on different degrees; and the latter by two notes a semitone apart, but standing on the same degree, and bearing the

The diatonic semitone is taerefore a minor same name. second; the chromatic semitone a sort of exaggerated unison. The pupil now proceeds to the order in which the major diatonic scales follow each other, according to the number of sharps or flats required to place the semitones in their proper positions. A table is then presented to him, showing the order, commencing on Do, ascending by fifths requiring sharps, and descending by fifths requiring flats. This table is used for occasional reference by the pupil. The teacher next explains the minor scale, the difference between the major and minor scales in the succession of tones and semitones ascending and descending, &c.; for which purpose Wilhem employs the vocal ladder, showing that, in the minor scales, the third of the scale is always minor; hence the name The tones are marked semitones <<.

Then follows a table with the major scales and their relative minors, having the same signatures.

Having hitherto only learned common time, with an even number of beats in each bar, the pupil's attention is now directed to time, with an uneven number of beats in the bar, called triple time, to practise which three beats are made in each, but in an opposite direction from the former. In the commencement of the study, the pupil is taught the three clefs, but only one has been practised, namely, the Sol clef. Having advanced thus far, Wilhem again introduces the large stave of eleven lines, with its principal divisions, by the Sol, Do, and Fa clefs, and also shows that the large stave of eleven lines can be subdivided into seven staves of five lines each, according to the extent of the different voices. The pupil is next taught how to transpose any piece of music from one scale to another, by changing the signatures, and using different clefs; but it is unnecessary here to present examples of the manner in which this is done; for full infor mation on the subject, we refer to the accessible works of Wilhem and Hullah.

THE external appearance of the human body is necessarily familiar to all. Its internal structure, however, and the manner in which its different functions are performed, are not understood as they ought to be by the generality of people. The more fully that we comprehend the structure of our frame, the more attentive shall we be to its preservation in a state of health, and the more capable of accomplishing that all-important object. The present treatise will therefore be devoted to a description of the human body, in language as popular as the subject will permit, and as concise, at the same time, as possible.

Zoological science places the human being in the class of Mammalia, or suck-giving animals, and in the order of Limana, comprising the two-handed creatures of that class. An erect posture is the peculiar characteristic of man, and it is one which gives to his aspect that dignity becoming his high place in creation. By the adaptation of an erect structure, also, his hands are left disengaged, and ready for the numerous operations to which he is inclined by his judgment or urged by his wants. His general stature is between five and six feet. A combination of hard and soft parts forms the material of his frame, the soft portions being arranged, generally speaking, upon and around the more solid parts of the structure. These latter parts consist of a beautiful framework of bones, termed the skeleton, which naturally occupies the first place in our description. Muscles and tendons, which are the organs of locomotion; the brain and nervous system, or organs of sense, feeling, and intellect; the lungs, for respiring the air essential to the main tenance of the principle of life; the stomach and digestire organs, for the supply of nourishment; the heart, blood-ressels, and absorbents, for the circulation of vital fluids through the body;-these and other important parts will fall to be described after the solid framework on which they rest has received its due share of our attention.

The skeleton comprehends three main divisions, the head, trunk, and extremities, which consist, in all, of 254 bones, joined together in a manner combining great strength with ease and freedom of motion. The whole of the bones are composed of nearly the same materials, namely, earthy matter, chiefly lime, and gelatine or animal glue. The lime gives them hardness and solidity, while the animal matter cements or binds them together, and renders them not easily broken. They differ to some extent in solidity and weight. A middle-sized adult skeleton, weighed all together, ranges between 160 and 200 ounces, or from 10 to 13 pounds avoirdupois. The heaviest bones in the body, in proportion to their size, are the bones of the skull, extremities, and pelvis, or under part of the trunk. Their surface is for the most part smooth, and the interior, beneath a cake or coating of more condensed substance, is porous and spongy. The bones of the extremities are hollow, like pipes, by which arrangement they are rendered at once light and strong. The marrow is contained in the internal cavity. Compact as they are, the bones are nevertheless pervaded by blood-vessels, which, indeed, are essential to their vitality.

nally, are the remaining bones of the head. The union of these bones is remarkably firm and strong in the adult being. In some cases, the osseous plates are joined by serrated or ragged edges, like the teeth of a saw. In other instances, they overlap each other, like the ridge of a house; the arrangement, in each case, being precisely the one best fitted to ensure strength and stability in the particular part. Altogether, an arch of the most powerful kind is formed, for the safe protection of the important organ within, the brain. The bones of the face, situated below and before the cranium, are nume rous. Among the facial bones are reckoned the tw upper maxillary or jaw bones; two malar or cheek bones; two nasal or nose bones; two small bones, at tached to the nose internally, called the turbinated bones two palate bones; the two lacrymal bones, situated in the orbit; the vomer, or ploughshare bone, forming a part of the basis of the nose; and the single lower jawbone or maxillary bone of the lower jaw.

The

The bones of the skull and face rest upon the top of the spine or backbone, which consists of twenty-four separate pieces, called vertebræ, firmly and curiously jointed the one into the other. The column of the spine is curved in several places, the most prominent being a curve forwards near the middle of the back. Seven of the vertebræ are called cervical, twelve dorsal, and five lumbar, from being situated respectively in the neck, back, and loins. Each vertebra has various projections and depressions, to admit of a firm union with those adjoining it; and, by the junction of the whole, a long hollow or canal is made, for the reception of the spinal marrow. In the annexed figure, the upper part of the vertebral column is marked ά, and the lower a. second of the vertebræ of the neck sends upwards a projecting pinion or tooth, which is received into a corresponding depression in the one above, thus forming the pivot upon which the head turns. The bones of the spine rest upon the pelvis, s s, a hollow, basin-shaped cavity, which is formed of two large bones, and composes the lower part of the trunk, giving to it firmness and stability. The spine rests on it by means of the sacrum, w, a series of five imperfect vertebræ, consolidated into one piece in advanced life, which sink like a wedge between the pelvic bones of each side. The sacrum terminates in a loose osseous peak, called the os coccygis. The strong, hollowed, cup-like bones of the pelvis, are marked by large round depressions on the outer and under surface of each, which form sockets for the two upper bones of the leg. At the top of the spine, immediately below the vertebrae of the neck, are situated on each side the collar-bones or clavicles, y y, which are long and narrow in shape, and pass in a semicircle or arch from the front of the chest backwards, or, in other words, from the sternum, x (breast-bone), to the top of the shoulders. On the back of the ribs, at each side, lie the shoulder-blades or scapula, which are thin flat bones, of a triangular shape. They rest loosely on the back, having scarcely any attachment except by muscles to any of the neighbouring bones. By this means they have a

A ligamentous band keeps the tooth-like projection of the second vertebra in the depression of the first. Nothing can better show how completely our life, during every instant of its duration, depends on the maintenance of every single part, however minute, in order. If this ligament, scarcely thicker than strong paper, were to give way, instant death, from pressure on the spinal marrow, would ensue. A porter, carrying a burden, dropped down dead. On examination, no cause of death could be found, till this apparently petty ligament was noticed to have given way, producing instantaneously the fatal

attached, on each side, to the scapula. A very small cavity in the latter bone admits the round ball-like head of the humerus, giving to it the most unconfined play of movement, whether of a rotatory kind, upwards, downwards, or sideways. Nothing can be more beautiful than the whole arrangements for permitting the arm to perform the multifarious motions which man requires from it. The humerus, a single bone in each arm, b b, cylindri- | cally shaped, is united at the elbow-joint, c c, to the two bones of the fore-arm, termed the radius, d d, and ulna, e e. One of these, the ulna, is attached to the humerus, by a hinge-joint (like that of a common door), while the radius is connected to the same bone by a round buttonlike head, which, being slightly concave, receives a projecting knob of the humerus, and admits of rotatory movements being performed by the lower part of the arm. These peculiarities of structure are essential to the free use of the hand. At the wrist, the position of the radius and ulna is in some measure reversed, the radius forming with the carpal bones, ƒ ƒ, a joint like that of a door-hinge, while the ulna is in a measure left loose. The carpal or wrist bones are eight in number. They are of small size, and lie in two rows, being jointed together in a manner that combines great strength with a certain degree of mobility. In the direction of the points of the fingers, they are united with the metacarpal bones, forming the palm of the hand, and to which the phalanges, g g, or finger bones, are attached. Each finger has three bones in it; the thumb has only two. As has been said, the bones of the pelvis, on each side, are marked by deep cup-like concavities, which receive the heads of the thigh-bones, h h, i i (femur), the upper bones of the lower extremities. As was required by the different nature of the purpose to be served, the ball-and-socket joint of the leg is much stronger than nat of the arm, and permits of much less freedom of

|

motion. The femur or taigh-bone is a rounded cyhn drical bone, terminating at the knee in a connection with the tibia, m, the principal bone of the inferior part of the lower extremity. The knee-joint is a hinge one, but permits of a slight rotatory motion when the leg is bent. The tibia has a smaller bone, the fibula, n n, placed by its side, and over the knee-joint is situated a small bone called the patella, ll, or knee-pan, to which the principal muscles that move the joint are attached, and which serves to protect the parts against injury. The tibia and fibula form a union at the ankle, o o, with the bones of the tarsus, which are seven in number, and constitute the heel or back part of the foot. These again are united to the metatarsal bones, p p, forming the body of the foot, and five in number. To these again are joined the phalanges of the foot, fourteen in all, two being attached to the great toe, and three to each of the others.

The cost or ribs, r r, proceed from the vertebræ or backbones, and are twelve in number on each side. They bend round in a circular manner from their point of union behind, and seven of them, called the true ribs, are joined directly by gristle or cartilage to the breastbone, while the remaining five terminate anteriorly in a common cartilage, which unites with the sternum below. Altogether, the ribs form a large hollow space for the reception of the lungs, heart, and other organs, and protect them from injury. The ribs move in an easy joint formed with the backbone, and, with the intercostal muscles, contract and expand to suit the motions of the lungs.

These are the principal bones forming the skeleton of the human being. All animals have not this osseous framework; it is only found in a certain number of classes, including man, quadrupeds, birds, reptiles, and some fishes, all of which, from the principal feature in their structure, are called vertebrated animals. Some of the other tribes of beings have their framework, corresponding in purpose to bones, on the outside of the body, in the form of a coat of mail. This is the case with the shellfish, as the lobster, and with many insects that have a hard external covering, as beetles.

THE MUSCLES.

aly substance, that serves to lubricate the joints, and facilitates the play of the tendons. There are from four to five hundred muscles in the human body, all necessary for performing the various movements and operations of the complicated machine. On each side of the backbone there are several layers of strong muscles, which are fixed by tendons to every projection of the numerous lones composing the spine. These muscles keep the trunk of the body erect, and also permit of the varous motions of the back. There are a multitude of Sall muscles about the face, head, and eyes, whose various action imparts that expression to the human countenance which indicates the prevailing feelings and passions of the individual. The tongue is also supplied by intricate muscular nores, giving to it that amazing volubility of action by which the vast number of sounds composing language are expressed. Many are attached to the lower jaw; but two in particular, the temporal muscles, proceed upwards through an arch formed by a projecting arm of the temple-bone, and are fixed to the tendons of the head. These two muscles are the most powerful in moving the jaws in the operation of chewing the food, and are very large in several animals of prey. Another flat muscle inside the cheek is called the trumpeter-muscle, because it assists in blowing from the mouth and in sounding wind instruments. The chest is supplied with numerous muscles, which move the ribs upwards and downwards in the action of breathing. A large flat muscle, called the diaphragm, stretched across the trunk from side to side, and separating the hollow of the chest from that of the belly, also contributes mainly to the process of breathing. The arm and hand are rolled inward and outward by a set of muscles, which are placed on the outer and inner sides of the respective bones; thus, the outside muscles act in a contrary manner to the inside, and reverse motions may be alternately performed. The muscles of the fore-arm are fixed to the scapula or shoulder-blade, to the chest, and to the clavicle, at the upper end, and to the bone of the arm at the other. The fingers are moved by muscles situated in the forepart of the arm, and have long slender tendons, by which they are attached. Two beautiful provisions of nature are here observed: at the wrist, a circular ring of tendinous substance binds down the long tendons, which would, in their various motions, otherwise start up from their places. This ring at once keeps them in place and permits their free and unhampered play. The other provision is seen in the construction of the tendons of the fingers. There are two principal muscles which move the joints of the fingers, and two sets of tendons, which are inserted, the one into the middle bones of the finger, the other into the third row of bones, or the extremities of the finger. In order to preserve their free action, and to make them lie in the most convenient manner, there is a loop or slit in the shorter tendon, by which the other passes through to its insertion in the point of the finger. By this means, the longest and strongest muscle moves the extremities of the finger, where the greatest power is wanted, without impeding the action of the other. The muscles which move the lower extremities are thicker and more powerful than those of the arms. Several large muscles, acting in opposition to each other, are situated around the thigh-joints, and move them. They are fixed, one end to the trunk of the body, some pretty far up, especially two, which are spread upon the front of the abdomen or belly, on each side of the spine, while the other ends are attached to the thigh-bone. Several thick muscles, also, are situated at the back of the trunk. Two large muscles compose the calf of the leg, and join to form the tendon of Achilles, which is fixed to the heelbone; these muscles act powerfully in bending the ankle and in supporting the body in walking. The foot and toes are moved by several long slender muscles, situated in the leg, which have tendons attached to them, and

terminating on the toes, exactly like those of the hand and fingers. The pelvis and lower limbs of man differ greatly from those of all other animals in their superior proportional strength, and in the number and fulness of the muscles. This was necessary, as man has been evi dently intended by nature for the erect position. In the monkey tribe, whose general form approaches nearest to that of man, the narrowness of the pelvis or hip-bones, and the smallness of the muscles of the lower extremities, clearly show that they were not destined by nature for the erect attitude; in fact, all animals of this class are furnished with four hands or paws, the hinder pair exactly resembling those in front. When they attempt to walk on the hind extremities, they cannot put the sole to the ground, but press on it edgeways. By the nice balanc ing of the muscles, and the great force which they exert, man is enabled to stand erect, and to maintain a firm position, or move forward at pleasure, notwithstanding that the body diverges from the perpendicular line of the centre of gravity. The head is also balanced upon the neck by means of strong muscles, whose constant though unobserved exertion is necessary to maintain it in its position; for in young children, when the muscles are as yet weak, and in persons asleep, the head has an incli nation to droop, and in the dead body it falls down or the shoulder or breast. The muscles of the neck, therefore, may be said to exercise a power in some degree in voluntary, or not under the command of the will, as the majority of the muscles of the body are. But there are other muscles still more distinctly removed from under the guidance of the will. The heart is nothing else than a hollow muscle, which contracts and expands without the consciousness of the being; and, in like manner, the muscles which perform the act of respiration are not moved by the will. This division of the muscles into two classes shows, as perfectly as any thing could do, the care with which our frame is constructed. Had those muscles on which respiration and the action of the heart depend, been placed under the control of the being, their functions would have been liable to be impeded, at every turn, by circumstances. Now, these organs cannot cease to act for the most trifling period of time, without fatal consequences. The arrangement, therefore, which renders their operation involuntary, is one to be admired as essential to life and comfort.

THE BLOOD-BLOOD-VESSELS.

The Blood. The blood is the medium by which all the solid and fluid parts of the body are supplied with nourishment. In its composition, therefore, will be found the majority of the substances of which the body is composed. The blood consists of a solid coagulable matter, called fibrin; of a series of red globules which form the colouring matter; and of serum, or whey-like matter, which gives the whole the necessary fluidity. From the heart, the centre of the circulation, the blood is conveyed through the body by vessels called arteries, and is brought back to the same part by veins. The purpose of its thus making the circuit of the whole body, is to supply the necessary materials for increasing the bulk and repairing the daily waste which takes place by perspiration and the perpetual operation of the numerous excretory organs. blood is restored to its nutritious state by the chyle, a juice formed in the stomach and intestines from the digested food; this chyle reaches the heart by one of the large veins called the left subclavian; from the right side of the heart it goes along with the venous blood to the lungs, and there it is mixed with the oxygen, or vital portion of the atmospheric air, by which process it is converted into bright red arterial blood. In short, there are two distinct circulations of the blood in the system. By the one, the blood is conveyed and distributed over all parts of the frame, imparting, at every pulsation of th heart from which it issues, new life and nourishment to

The

the whole. After traversing the body, it returns to the heart, deprived of its nutritious properties, and changed in colour from a bright to a dark red. Here the second circulation, which is through the lungs, commences. The blood is poured from the right side of the heart, which has divisions for the purpose, into large vessels which carry it to the lungs, and, spreading out into countless branches, penetrates and permeates their whole substance. Collected again by other vessels of equal number and extent, it is conducted by them to the left side of the heart, to be propelled anew through the frame, restored to its bright red hue, and repossessed of all its vivifying qualities. Both these changes are effected in the lungs. The chyle, which may be called the essence of our food in a liquid state, is conveyed from the stomach through the chest by a duct, which empties itself into one of the veins, immediately before the blood is transmitted through the lungs. It is in these organs that the chyle is thoroughly mixed up with the circulation; and it should be remembered, that this chyle is the only benefit, the only real food, extracted from all the substances received into the stomach, the remainder being entirely useless and excrementitious. From the chyle comes the material of the bones, of the fleshy or muscular parts, of the brain and nervous cords, of the hair, nails, enamel of the teeth, and, in short, of every different structure of the system. The average quantity of blood contained in an ordinary-sized person, is calculated at about 30 lbs. weight. The coloured globules of blood do not enter into the smallest vessels of the body, but only the thinner part of it, which has no colour; thus, in the eye, there are numerous bloodvessels, but these are so minute as not to admit the red parts of the blood; and this is a necessary provision of nature, in order that these organs may retain their pure transparency for the purpose of vision. In inflammation of the eyes, when these vessels are much enlarged, the red globules sometimes enter, and the eyes are then said to be blood-shot. What is called the pulse, is the flow of the blood through the arteries, which is caused partly by the impulse of the heart's contractions or beatings, and partly by the contractions of the coats of the arteries. The rate of pulsation in a person in the prime of life, is from 65 to 75 beats in a minute. In childhood the pulse is much quicker-from 100 to 140 beats; and in old age it again becomes slower than the medium standard. In fevers, inflammations, and other diseases of excitement, the action of the heart is increased sometimes to form 100 to 140 pulsations in a minute.

Blocd-Vessels. These consist of the heart, with its arteries and veins, that branch out through every part of the body, and carry the blood, by constant circulation, through them. The heart is placed in the left side of the chest, a cavity divided into two parts by a thin membrane running perpendicularly down the centre, and supported below by the diaphragm. It is of a round or conical shape, with the base or broad part uppermost, and the point slanting downwards and towards the front surface of the chest. It is of a thick muscular substance, with hollow cavities inside, and numerous cords or pillars of fleshy or tendinous substance stretching through these to give them support. In man and all the more perfect animals that breathe air through the lungs, it is double, or has two distinct sides, each performing separate offices. In fishes, again, the heart is single; in insects there is no proper heart, but a vessel that runs along the back; somewhat like an artery, through which the fluid corresponding to blood circulates through their bodies; other animals, still more simple in structure, have no trace of heart or blood-vessels. For these ends, the heart in man has two sides, a right and left; and each of these sides contains two hollow cavities-the one called an auricle, from its fancied resemblance to a dog's ear; the other a ventricle, or belly. The manner in which the circulation of the blood is effected may thus be described in detail:

Two large veins, one from the upper part of the body, the other from the lower, enter the right auricle of the heart, and carry the blood, which has made the round of the body, into this cavity. Here it is of a dark purple colour, and it is called venous blood, from its coming from the veins. From the right auricle it is sent, by a sudden contraction or forcing together of the two sides of the cavity, into the right ventricle, immediately below the auricle, and communicating with this by a small opening furnished with a valve; by the right ventricle con tracting, it is conveyed by the pulmonary arteries intc the lungs, the two large cell-formed substances on each side of the chest, surrounding the heart. After passing through the lungs it is returned by the pulmonary veins to the left auricle of the heart; from this it is sent into the adjoining left ventricle; and, by a powerful contraction of this muscular cavity, it flows out by the great artery of the heart, the carotid, which distributes it through every part of the body, again to be returned by the veins: and thus the round of circulation is continually going on.

The heart being an extremely thick muscle, the force with which it contracts is very considerable. The left ventricle of the heart, too, although somewhat smaller, is much thicker and more muscular than the right, it having to send the blood through the whole of the body. A beautiful provision is observable in the heart, to prevent the flowing back of the blood into its different cavities during their alternate pulsations. In the passage of communication between the left auricle and ventricle are placed valves, which, when the ventricle contracts to send the blood through the aorta, close accurately, so as to prevent a reflowing into the auricle. There is the same provision between the right auricle and ventricle, and also at the mouth or commencement of the aorta and pulmonary arteries, and the veins which communicate with the right auricle. Some of these valves are of beautiful structure; they are composed of three flaps that join accurately over each other; and to prevent their being pushed by the impetus of the blood beyond their proper position, they have little tendinous cords attached, of exactly the length required. In the child before birth, as it cannot breathe, and therefore the lungs are not used, there is a small hole or communication between the right and left auricles, by which the blood from the veins flows directly through the arteries, and thus avoids going to the lungs; this hole closes up whenever the child begins to respire. The aorta, or great artery of the body, after it leaves the heart, passes upwards in the form of an arch, when it gives off the carotid branches to supply the brain, and face, and arteries to the arms and chest. It then bends downwards, and gives off branches to the stomach and other viscera; and when it comes to the lower part of the belly, it divides into two main parts, which become the arteries of the pelvis, thighs, and legs. The arteries of the body are composed of three coats or coverings, the principal one being a thick muscular ring, which encircles the artery, and which contracts and expands so as to assist in sending the blood onwards. The principal trunks of the arteries lie deep in the fleshy parts of the body, but their ramifications are so numerous and minute, that they pervade every particle of the human structurebones, gristle, and every other texture. These extreme branches of the arteries being so minute, anatomists have had great difficulty in tracing the exact point at which they pass into veins. That they do so, however, is undeniable, and is partly seen on the surface of the brain. The veins are another system of vessels, which return the blood from the extremities of the body to the heart. They are larger and more flaccid than the arteries, and are distinguished from them by having no pulsation. A large vein generally accompanies the corresponding artery, but the great proportion of the veins lie more towards the surface, and are easily distinguished, swelling out under the skin. The numerous veins from the lower extro