strings or wires. If the muscles which move the fingers had been placed in the palm or back of the hand, they would have swelled that part to an awkward and clumsy thickness. The beauty, the proportions of the part, would have been destroyed. They are, therefore, disposed in the arm, and even up to the elbow; and act by long tendons, strapped down at the wrist, and passing under the ligaments to the fingers, and to the joints of the fingers, which they are severally to move. [Pl. XIII. fig. 1, 2.] In like manner, the muscles which move the toes, and many of the joints of the foot, how gracefully are they disposed in the calf of the leg, instead of forming an unwieldy tumefaction in the foot itself! The observation may be repeated of the muscle which draws the nictitating membrane over the eye. Its office is in the front of the eye; but its body is lodged in the back part of the globe, where it lies safe, [Pl. IV. fig. 2, 3,] and where it encumbers nothing.*

V. The great mechanical variety in the figure of the muscles may be thus stated. It appears to be a fixed law, that the contraction of a muscle shall be towards its centre. Therefore, the subject for mechanism on cach occasion is, so to modify the figure, and adjust the position of the muscle, as to produce the motion required, agreeably with this law. This can only be done by giving to different muscles a diversity of configuration, suited to their several offices, and to their situation with respect to the work which they have to perform. On which account we find them under a multiplicity of forms and attitudes; sometimes with double, sometimes with treble tendons, sometimes with none: sometimes one tendon to several muscles, at other times one muscle to several tendons. The shape of the organ is susceptible of an incalculable variety, whilst the original property of the muscle, the law and line of its contraction, remains the same, and is simple. Herein the muscular system may be said to bear a perfect resemblance to our works of art. An artist does not alter the native

*The convenience and beauty of the tendons seem only an ulterior object, their necessity and utility principally claim our attention. The force which a muscle possesses is as the number of the muscular fibres; but a limited number of fibres only can be fixed to any certain point of bone destined to be, noved, therefore the contrivance is, to attach them to a cord, called a sinew or tendon, which can be conveniently conducted and fixed to the bone. If we are desirous of moving a heavy weight, we tie a strong cord to it, that a greater number of men may apply their strength. Thus a similar effect is produced-the muscular fibres are the noving powers, the tendons are the cords attached to the point to be moved.-Paxton.

quality of his materials, or their laws of action. He takes these as he finds them. His skill and ingenuity are employed in turning them, such as they are, to his account, by giving to the parts of his machine a form and relation, in which these unalterable properties may operate to the production of the effects intended.

VI. The ejaculations can never too often be repeated;How many things must go right for us to be an hour at ease! how many more, to be vigorous and active! Yet vigor and activity are, in a vast plurality of instances, preserved in human bodies, notwithstanding that they depend upon so great a number of instruments of motion, and notwithstanding that the defect or disorder sometimes of a very small instrument, of a single pair, for instance, out of the four hundred and forty-six muscles which are employed, may be attended with grievous inconveniency. There is piety and good sense in the following observation taken out of the Religious Philosopher: With much compassion," says this writer, as well as astonishment at the goodness of our loving Creator, have I considered the sad state of a certain gentleman, who, as to the rest, was in pretty good health, but only wanted the use of these two little muscles that serve to lift up the eyelids, [Pl. XIV. fig. 1, 2,] and so had almost lost the use of his sight, being forced, as long as this defect lasted, to shove up his eyelids every moment with his own hands!" In general we may remark, how little those who enjoy the perfect use of their organs, know the comprehensiveness of the blessing, the variety of their obligation. They perceive a result, but they think little of the multitude of concurrences and rectitudes which go to form it.

Besides these observations, which belong to the muscular organ as such, we may notice some advantages of structure, which are more conspicuous in muscles of a certain class or description than in others. Thus:

I. The variety, quickness, and precision, of which muscular motion is capable, are seen, I think, in no part so remarkable as in the tongue. It is worth any man's while to watch the agility of his tongue; the wonderful promptitude with which it executes changes of position, and the perfect exactness. Each syllable of articulated sound requires for its utterance a specific action of the tongue, and of the parts adjacent to it. The disposition and configuration of the mouth, appertaining to every letter and word, is not only peculiar, but, if nicely and accurately attended to, perceptible to the sight; insomuch, that curious

persons have availed themselves of this circumstance to teach the deaf to speak, and to understand what is said by others. In the same person, and after his habit of speaking is formed, one, and only one, position of the parts, will produce a given articulate sound correctly. How instantaneously are these positions assumed and dismissed! how numerous are the permutations, how various, yet how infallible! Arbitrary and antic variety is not the thing we admire; but variety obeying a rule, conducing to an effect, and commensurate with exigencies infinitely diversified. I believe also that the anatomy of the tongue corresponds with these observations upon its activity. The muscles of the tongue are so numerous and so implicated with one another, that they cannot be traced by the nicest dissection; nevertheless (which is a great perfection of the organ,) neither the number, nor the complexity, nor what might seem to be the entanglement of its fibres, in anywise impede its motion, or render the determination or success of its efforts uncertain.

I here entreat the reader's permission to step a little out of my way, to consider the parts of the mouth, in some of their other properties. It has been said, and that by an eminent physiologist, that, whenever nature attempts to work two or more purposes by one instrument, she does both or all imperfectly. Is this true of the tongue, regarded as an instrument of speech, and of taste; or regarded as an instrument of speech, of taste and of deglutition? So much otherwise, that many persons, that is to say, nine hundred and ninety-nine persons out of a thousand, by the instrumentality of this one organ, talk, and taste, and swallow, very well. In fact, the constant warmth and moisture of the tongue, the thinness of the skin, the papillæ upon its surface, qualify this organ for its office of tasting, as much as its inextricable multiplicity of fibres do for the rapid movements which are necessary to speech. Animals which feed upon grass, have their tongues covered with a perforated skin, so as to admit the dissolved food to the papillæ underneath, which, in the meantime, remain defended from the rough action of the unbruised spiculæ.*

Papillæ are small bodies situated on the surface and sides of the tongue; they are furnished by the extreme filaments of the gustatory nerve, through which medium we acquire the sense of tasting. In herbivorous animals the papillæ are sharp pointed and directed backwards to assist in laying hold of the grass. In the cat kind there is a horny or prickly set covering the tongue, rendering it rough, and enabling it to

There are brought together within the cavity of the mouth more distinct uses, and parts executing more distinct offices, than I think can be found lying so near to one another, or within the same compass, in any other portion of the body: viz. teeth of different shape,* first for cutting; secondly for grinding: muscles, most artificially disposed for carrying on the compound motion of the lower jaw, half lateral and half vertical, by which the mill is worked: fountains of saliva, springing up in different parts of the cavity for the moistening of the food, whilst the mastication is going on: glands,† to feed the fountains; a muscular constriction of a very peculiar kind in the back part of the cavity, for the guiding of the prepared aliment into its passage towards the stomach, and in many cases for carrying it along that passage; for, although we may imagine this to be done simply by the weight of the food itself, it in truth is not so, even in the upright posture of the human neck; and most evidently is not the case with quadrupeds, with a horse for instance, in which, when pasturing, the food is thrust upward by muscular strength, instead of descending of its own accord.

In the meantime, and within the same cavity, is going on another business, altogether different from what is here described, that of respiration and speech. In addition therefore, to all that has been mentioned, we have a passage opened, from this cavity to the lungs, for the admission of air, exclusively of every other substance; we have muscles, some in the larynx, and without number in the tongue, for the purpose of modulating that air in its passage, with a variety, a compass, and precision, of which no other musical instrument is capable. And, lastly, which in my opinion crowns the whole as a piece of machinery, we have a specific contrivance for dividing the pneumatic part from

take firmer hold of the prey. Birds also have a similar contrivance. In fish the tongue is covered by a number of teeth, serving the same purpose. Paxton.

*In each jaw there are four incisores, or cutting teeth, two canine which may be ranked with the former, only more pointed; four small molar, and six large molar or grinding teeth. And as the teeth of animals indicate the food on which they are destined to subsist, so from analogy we may infer that man is called to use either animal or vegetable aliments, or both, i. e. keeps a mean between graminivorous and carnivorous animals, in the structure and complication of his digestive apparatus, without deserving on that account to be called omnivorous: for it is known, that, a great number of the substances upon which animals feed are of no use in the support of man.-Paxton.

The principal of these are the parotids, see Plate XX.

the mechanical, and for preventing one set of actions in terfering with the other. Where various functions are united, the difficulty is to guard against the inconveniences of a too great complexity. In no apparatus put together by art, and for the purposes of art, do I know such multifarious uses so aptly combined, as in the natural organization of the human mouth; or, where the structure, compared with the uses, is so simple. The mouth, with all these intentions to serve, is a single cavity; is one machine; with its parts neither crowded nor confused, and each unembarrassed by the rest: each at least at liberty in a degree sufficient for the end to be attained. If we cannot eat and sing at the same moment, we can eat one moment, and sing the next: the respiration proceeding freely all the while.

There is one case, however, of this double office, and that of the earliest necessity, which the mouth alone could not perform; and that is, carrying on together the two actions of sucking and breathing. Another route, therefore, is opened for the air, namely, through the nose, which lets the breath pass backward and forward, whilst the lips, in the act of sucking, are necessarily shut close upon the body from which the nutriment is drawn. This is a circumstance which always appeared to me worthy of notice. The nose would have been necessary, although it had not been the organ of smelling. The making it the seat of a sense, was superadding a new use to a part already wanted; was taking a wise advantage of an antecedent and a constitutional necessity.

But to return to that which is the proper subject of the present section-the celerity and precision of muscular motion. These qualities may be particularly observed in the execution of many pieces of instrumental music, in which the changes produced by the hand of the musician are exceedingly rapid; are exactly measured, even when most minute; and display, on the part of the muscles, an obedience of action, alike wonderful for its quickness and its

correctness.

Or let a person only observe his own hand whilst he is writing; the number of muscles which are brought to bear upon the pen: how the joint and adjusted operation of several tendons is concerned in every stroke, yet that five hundred such strokes are drawn in a minute. Not a letter can be turned without more than one, or two, or three tendinous retractions, definite, both as to the choice of