of life not present him with fufficient means to dazzle the eyes of the world with the fplendor of riches; should ambition, enVIOUS of his happiness, turn him out of the road which leads to honours in a civil capacity; fhould military exploits prove for him a fuccefslefs enterprife; he may at least, by memorable words, fentiments, and actions, convince Fame, that he is so far worthy of her patronage, as to be fequeftered by her from the ignoble and unthinking part of his species. Thus it is with an author, who has nothing more very often to recommend him but his genius; but this genius fhould be uncommon, though, by an exact ftudy of nature, what it produces, may flatter, yet impotently, any other with the hopes of effecting the fame; this genius fhould conftantly exprefs a heavenly origin, and, by foaring boldly adventurous to immortality, fhould defpife all abject concerns. But, if feconding by a fort of greedy pursuit, this instinct of grandeur, implanted in our minds, be a fource of true fublime in fome authors, it cannot be reputed fo in others; for, though all naturally love and aim at magnificence, their endeavours for its acquifition turn out not feldom very delufive, and engage them in feveral remedilefs errors. This happer by reason of a superficial fund of judgement in the genius, which therefore must suffer itself to be impofed upon by a phantom only of perfection; and from this caufe, as fo many effects, may be derived all the overftrainings of nature, all the ex

travagance of thought, all the monstrous fwellings of style, cold conceits, infipid witticifms, ftrange allufions, with a multitude of other oddities and corruptions. Confult nature conftantly,' is a precept which cannot be too often inculcated, and may justly be faid to be as conducive to well writing, as Know thyself,' is to the fulfilling of the moral duties of life. Nature is fituate in a medium between two extremes; adhere to one, you stoop to basenefs; embrace the other, you grafp at clouds; look to the intermediate space, you find beauty in proportion, and proportion in beauty, a never fading luftre, pomp, juftness, and elegancy. How nobly does the great foul of Seneca inftruct his friend in one of his Letters *, where he says: "I would not have thee be too anxious about words and compofition; there are things of greater moment which deferve thy attention. Search after what thou shall write, and not how. Whatever difcourfe thoa perceiveft follicitous and nice; remember that the mind of its author is taken up with trifles. The great author is nervous and fecure; what he fays has a greater air of confidence than care. Thou knoweft many a town beau big with flirts, and all the modifh whims of drefs. From fuch hope for nothing folid, nothing vigorous. A piece of writing is the visage of its author's mind: If decked out, combed, trimmed, and daubed with fulfome paint, it must degrade nature, and be a notable memorial of inward corruption.'

HE first object of anatomy, and the

the knowledge of the parts that enter the compofition of the human body; But this important object is in a great measure alluf. trated, when even we ftudy the interior parts of animals whofe ftructure feems to be very different from ours. This ftudy, called comparative anatomy, abounds with curious incidents, and, among other particulars, lets us fee the difference between the organs employed by the Author of Nature in different animals for attaining the fame ends, and producing a fimilarity of effects.

Those destined for forming the voice of man have been but indifferently obferved by the ancients. The trachean artery, or wind

voice according to the founds of that inftru

ment.

Galen feems to be the first that thought the glottis was the principal organ for producing it.

But it was referved to the illuftrious M. Dodart to fhew us, in two excellent memoirs printed among thofe of the Academy. how to admire an inftrument fo fimple in appearance. In them he confiders the glottis as both a ftring and wind inftrument, and more incomparably perfect than those of either kind art is productive of.

M. Ferrein fince published an ample and learned memorial among thofe of the Academy of 1741, whereby he intended to let

in

in a new light the mechanism of the forma tion of the human voice.

The organs for forming that of animals, of different claffes, feemed to me deferving of more attention than is ufually paid them. Quadrupeds and birds of each fpecies have peculiar founds, whereby they understand each other, exprefs their wants, and perhaps their defires and fentiments. In what refpect do the organs granted them for forming thele founds refemble thofe that ferve us for the fame purpofe, and in what confifts their difference? The refearches I made to acquire fome information have been productive of obfervations that fhall furnish me with two parts for this memorial; the first on the organs of voice in quadrupeds, the fecond on those in birds. The comparisons I may make of organs with organs, prefuppofe its being known that naturalifts are now unanimously of opinion, that the glottis, or rather its lips, are the organs of the human voice.

However, a more competent judgment may be made of the effects the parts peculiar to certain animals are capable of producing, if a juft idea be conceived of the manner in which the human glottis acts; and it is therefore, I prefume, neceffary to give a place here to M. Dodart's fentiments on this matter, and in his own words:

The voice, fays he, cannot be formed but by the glottis. The tones of the voice being modifications of the voice, they must therefore be produced by the modifications of the glottis. But the glottis is capable of one only modification, which confifts of the mutual feparation and junction of its lips. The different tones of the voice must be produced thereby. This modification comprehends two circumftances; the one capital and primitive for the production of the voice; the other is only a confequence of it, but fo neceffary and infallible a one, that the first cannot be without the fecond. The firft is, that the lips, from the lowest to the higheft tone, are more and more bended; the fecond, that the more they bend the more they draw near. It follows, from the first, that their vibrations will be more frequent according as they come nearer the highest tone; and that the voice will be exact when the two lips are equally bent, and the reverfe when unequally, which coincides perfectly well with the nature of string mufical inftruments. It follows, from the fecond, that, the more they raise the tone, the more they draw near, which agrees perfe&ly with wind-inftruments governed by reeds. The degrees of tenfion in the lips are the first and principal caufe of tones, but their difference is little fenfible and with difficulty af

Let

fignable. The degrees of junction, or drawing near, are infeparable from the tenfion, the first cause of tones; but it is not fo eafy to conceive and affign thefe degrees. us therefore hold to that, in order to give a more exact idea of the matter; and let us say, that this modification confifts in a tenfion, whence refult the many fubdivifions of an interval of very finall extent; but, however Imall this extent may be, it is, phyfically speaking, capable of an infinite fubdi

vilion.'

The fame author adds: We cannot compare the cause that puts in motion the lips of the glottis (which he calls vocal) to any other than that which makes the kind of inftrument refound (if it can be fo called) that refults from the effect of an impetuous wind striking upon half-opened paper, which joins an ill glued frame with the gap of a window. I fhall call, fays he, this inftrument, for brevity's fake, the bluftering frame.'

All naturalifts have equally, with M. Dodart, admired the glottis, which, though fo fimple in appearance, produces fuch a variety of modifications in founds; but, as if they had believed nature's intire art exhausted in its conformation, they did not think it worthy of their notice to examine whether the voice of quadrupeds had any particulars deferving of being known. Lefs imperfect voices than the human might seem to require no peculiar mechanifm, because these animals have a glottis. But have they nothing more? Does it act in them as in man, because it acts more grofly? Is it an organ equally effential to the formation of their voice? Thefe are particulars I fhall undertake tó difcufs in the firft part of this memorial.

Among quadrupeds nature hath given to fome, as to man, nothing more, for the principal organ of their voice, than a glottis; and of this number are feveral of the moft familiar, fuck as the cat, fheep, bull, ftag, &c. A dromedary that died lately at Paris, and which I diffected, made appear also that the animals of the fame fpecies have only a glottis for the inftrument of their voice. Some variations notwithstanding are discoverable in thofe of different animals, but, being little ftriking, I need not dwell upon them, and may therefore place these animals in the clafs of those whom I fhall call with fimple organs. The quadrupeds of the fecond clafs may go under the denomination of thofe with compound organs, because they have fomething more than a glottis, or their organs are more compounded than we expected to find them; and fome even of this clafs are as familiar

objects

objects of our fight as any of the abovementioned. We might not perhaps imagine, that Nature had put herfelf, as it were, to greater expences for making an horse to neigh, an ass and mule to bray, an hog to grunt, than for rendering the human voice capable of letting us hear the most agreeable founds. She has however given to fome of thefe, befides the glottis, a tendinous membrane, difpofed with great art, which is to concur towards the formation of the voice, and even to bear therein a principal part. She has granted to others feveral membranes of a different fort; others the has provided with a kind of bags, more or lefs ample, and more or lefs thick, which in fome are membranous, and in fome others bony; others have been allotted by her particular membranes and bags; others, laftly, have in their larynx a certain cavity, or kind of drum, capable of rendering very ftrong and loud founds, as may appear from the examples I intend to recite of these more or lefs compound organs of the voice.

All founds in general are produced by prompt and fudden vibrations, in a rapid fucceffion from the particles of fonorous bodies that move and agitate the air with great velocity. The vibrations, the fluiterings of the lips of the glottis, would not be fufficient to produce the neighing of a horse. This kind of chaunt, if I may give it this name, begins by more or lefs acute interrupted tones, accompanied by quaverings, and ends by more or less grave tones, or more or lefs hoarfe, and performed by jerks. This fecond part of neighing is executed by the tendinous lips of the glottis, called, by M. Dodart, cords or ftrings in man; and the other is principally by a fmall elaftic membrane. Tho' I know of no author, who has mentioned it, one may eafily find it in the larynx of a horfe, and withal fee that it is very thin, very fine and tendinous; of a triangular figure, laid flat on each extremity of the lips of the glottis, near the thyroides cartilage, and confequently in part formed like a fcythe. As this membrane adheres but loofely to this place, it can easily flutter up wards and downwards on the tendinous lips of the glottis, much in the fame manner as the languet of metal in the tubes of an organ.

It will evidently appear that it is the play of this membrane that produces the acute founds of neighing, if the lateral parts of the larynx of a horfe newly killed are compreffed, in order to ftraiten the glottis, and if afterwards the air is ftrongly driven through the wind-pipe. Hereupon, the acute found will be heard very diftin&tly,

and may be more perfectly imitated by darting in the air by fmall jerks.

Moreover, if a flight transversal incifion be made on the tendinous fibres of the lips of the glottis, near the arythenoides carti lages, and if the air be introduced in the above manner, the fame acute founds will be heard as before, though the section has occafioned a manifeft relaxation in the lips.

The found of the elaftic membrane is still better procured by introducing in the lower part of the larynx a pipe of the bignefs of the little finger, placed a little below the membrane. This pipe being then blown into, the agility of the fluttering is immediately perceptible, and the loud found of neighing ftrikes the ear.

A jutt idea will be conceived of the mechanifm whereby a horfe produces founds like thofe formed by blowing into the windpipe, if this animal is attentively oblerved when he neighs. We fee that, after making a great infpiration, he contracts infenfibly his cheft, and renders it, as it were, immoveable, whilst the diaphragm, acting in concert with the mufcles of the abdomen by fmall jerks,' drives the air out with impetuofity, and at feveral times through the glottis, which is then ftraitened by the ap proach of the lips in a more or lefs tenfion; and thus it is that the air, rufhing with violence under the elastic membrane, towards which it is neceffarily directed by the ftructure of the parts, raifes it up and trikes it with great violence, and at feveral times to excite in it quick vibrations and interrupted flutterings. In fhort, the mechanism whereby this membrane is put in play, is precifely the fame with that we obferve in a fit of laughter, and the loud found of neighing is more acute, according as the tendinous and elastic membrane is more or less fine and thin, and its adhefions more or lefs flack and loofe, &c. for this varies according to the fubjects.

As to the grave founds, and by jerks, that conclude the neighing, it is certain they are excited by more or less flow flutterings of the ftrong and thick ftrings that form the lips of the glottis, which grow flack and loofe when the clear and acute found ceafes. Experience confirms this truth.

It is not to pleafe our ears by his voice, that the quadruped, reputed the fymbol of ignorance, has been allotted one fo hoarfe, fo ftrong, and so astonishing, that it must in a great meafure affright the perfon who fhould hear it the first time close by him. The organs that were neceffary, though deftined for producing fuch difagreeable founds in the afs, are not therefore lefs worthy of being known. They have been

i much

much more multiplied than those productive of the founds we covet to hear, and they prefent a mechanifm which will be admired by all thofe who are fenfible of the pleafure in feeing the beautiful variety Nature has embellished her works with.

The hoarfe found of the afs's voice is not for the greater part produced by the fluttering of the lips of the glottis, but principally by that of a part which feems to be more or lefs tendinous, and adheres loofely in the manner of a tympanum on the aperture of a kind of drum-cafe, formed by a deep hole of the cartilage thyroides. This tympanum has an almoft vertical direction, and is fituate at the extremity of the lips of the glottis, where there is a fmall aperture, having a communication with the cafe be hind the tympanum. Above the lips of the glottis, are alfo found two large and pretty thick bags, one of which is to the right, and the other to the left. Each of them has an almoft round aperture, and as it were cut like the stopple of an organ, turned towards that of the cafe.

Such is, in a great meafure, the ftructure and difpofition of the pieces that form principally the loud found, heard at a diftance from every expiration, when an afs puts in action the organs of his voice. A kind of drum, though different from thofe we ufe, is here the principal agent, and the two bags, above the lips of the glottis, appear to be auxiliaries. We shall now examine how thefe pieces are put in play.

Infpirations and expirations are fuccefvely repeated by the animal. The infpirations are fo confiderable, that he feems to be ready to be fuffocated by them, by reafon of the difficulty he meets with in a free fuction of the air from the contraction of the glottis. On the contrary, at the time of expiration, the fame animal feems to be at eafe, because the lips of the glottis are fufficiently relaxed to give the air an eafy vent from the lungs. During the infpirations, a kind of more or lefs acute wheezing or rattling is heard, occafioned by the air ftruggling to break in upon the lips of the glottis, fupposed to be contracted; and hence it is, that this air paffing between thefe lips, being in a greater or lefs tenfion, excites in them vibrations and futterings capable of producing a more or lefs acute found, which is heard when an afs draws in the air to drive it forth afterwards with a terrible noife. The air, being driven violently through the wind-pipe to go out by the glottis, is for the greater part ingulphed in the cavity of the drum, and lets the abovementioned kind of tympanum in vioJent flutterings. Hence refults a more or

I

lefs loud found, according as the tympanum is more or lefs thick, and the air that agitates excites in it more or less prompt flutterings.

It would appear to be a gratis dictum that the lips of the glottis contribute almost nothing to the formation of this loud found, had not we fully demonftrated the fame by experiments, which are easily repeated: Let the larynx of an afs be taken and separated almoft intirely from the lips of the glottis, near the arythenoides cartilages, and let the air be forcibly driven through a pipe of the bignefs of the little finger, and this pipe carefully placed a little below the aperture that communicates with the drum; a very perfect imitation will then be made of the found of the voice in question, though the lips of the glottis have fcarce then any tenfion. The fame experiment may be performed by blowing with the mouth through the windpipe, fo that care be taken to comprefs fufficiently, with the hand, the lateral parts of the larynx.

The mule's voice refembles much that of his fire, and in no respect that of a neighing horfe, fo that the organs whereby he forms founds are almost as numerous as thofe of the afs's voice, and conftructed much in the fame manner. The drurn, of fo fingular a compofition, which is found in the larynx of an afs, and not feen in that of the horse, has been granted to the mule: This is a fact whereof the knowledge cannot be indifferent to those that endeavour to fet in a better light the mystery of generation, and who think with M. Reaumur, with great probability, that the mules of different kinds of animals furnish us with the propereft facts for deciding which of the opinions, that divide naturalifts on fo important a matter, is the truer.

There is another animal we shall not place in the rank of the noble, being better placed in that of the most unfeemly of all, which affords us an example of a particular difpofition in the vocal organs. This is the hog, whofe voice grates not lefs upon our ears than the afs's when he fetches very piercing and acute cries; these cries are much less supportable than his usual grunting,

We have feen that in the horfe, the ass, and the mule the lips of the glottis, far from being the principal agents, contribute but little to the formation of the voice: The fame may be faid of the hog, the variety of whofe cries are not excited, for the most part, by the action of the lips of the glottis, but rather by the fluttering of two large membranous bags, which Cafferius fpeaks of in these words: Foramina duorum

ventrium

ventriam per quæ aer ingreditur ad grunnitum in porcis efficiendum.' The apertures of two bags through which the air enters to caufe grunting in hogs.' Each bag is fituated above one of the lips of the glottis, one on the right and the other on the left. But what is here remarkable is, that each lip is cloven throughout almost all its length, as if it was to form a small particular glottis befides the ufual one: This cleft of each lip is the place whereby it has a communication with the bag belonging to it, and this is the aperture of the bag, and thefe are the large bags that are put in motion for producing the greater part of the different founds peculiar to this animal.

When a bog has a mind to exert himself in cries, his glottis must be neceffarily contracted, whereupon the air expelled from the lungs, finding a difficult vent, proceeds partly into the large bags, where it finds lefs refiftance in entering, their apertures presenting themselves to it on its way; the bags fwell, and more prompt and violent flutterings are occafioned in them, according as the air darts in with more or less force, whence result more or less piercing cries.

This truth is easily evinced by the larynx of hogs newly killed; for, if the windpipe be blown with the mouth, and the lateral parts of the larynx fufficiently compreffed with the hand, the two bags will be immediately feen to ftrike and flutter against each other: This happens becaufe the action of the air which enters thefe two bags, and strives to fill and swell them, is counterbalanced, to a certain degree, by that of the current of the air flowing from the glottis; and this is what neceffarily produces the vibrations in the membrane that forms each bag; the interior air, or the air of the bags, ftrives to draw them near, and to make them ftrike against each other; and the current of the air of the glottis, which is too much straitened, feparates them; hence a kind of conflict arifes from the goings and returnings, in fhort, from the vibrations in the membrane of each bag.

If these bags are intirely taken away, on being properly detached from the interior of the larynx, and without altering the lips of the glottis, it will be in vain to make the air exert itself as before, or expect to

hear the fame founds.

The ufe of the bags is ftill better proved when the tendinous fibres of the lips of the glottis are relaxed, by making a tranfverfal fection towards the arythenoides cartilages, without endamaging the bags; for, if the air be afterwards driven through the trachea, with the fame precautions as above, almost all the fame founds are excited which

were heard when all the parts were intire ; I fay almoft, because it is certain, that, in order to the diftin&t formation of the founds in all forts of larynxes, it is necessary that all the parts of the interior of the larynx fhould be found and intire; for it must be allowed that they contribute each, in a particular manner, to the perfection of the different founds of voice.

Should a hog be attentively considered, when he utters the different tones of voice peculiar to him, it might be easily known, that the acute founds, as well as the hoarfe, of his grunting, are always produced when the air is expelled the lungs. This is what we cannot perfectly imitate, I mean the hoarfe founds of grunting, but by a brisk fuction of the air into the noftrils, and holding the mouth open.

Though the voice of birds feems to bear a nearer refemblance to ours, than that of quadrupeds, because fome of them amuse us with very agreeable songs, learn to fing airs, and attain to the imitation of our words; yet the organs of their voice are by far more different from ours, than those in quadrupeds, and, withal, contain a greater number of fingularities. Our glottis is placed at the entrance of the trachean artery: They have alfo one at the entrance of this duct; but the lips, being incapable of fufficiently prompt vibrations in their infenfible parts, contribute almost nothing to the formation of founds. This obfervation has been well proved by M. Perrault, who acknowledges in them a second larynx, which he calls internal; though he does not allow the fame to all in general. This internal larynx is where the trunk of the trachean artery terminates, that is, at the place of its bifurcation, where the organs are that ferve principally for the formation of founds. Thefe organs fhould also be diftinguished into a great number of others, whofe chief deftination, in birds, feems only for fortifying and modifying founds. Not one bird, as I could find, wanted this internal larynx fituated at the bottom of the trachea ; though I have seen it of a very different configuration.

The principal organs for the formation of the voice of birds confift of different membranes, more or lefs fine, more or less bent, and in a variety of pofitions. In certain birds, as in the goofe, &c. there are four of thefe membranes, figured and dif pofed as the reeds in hautboys. Thefe four membranes, being difpofed two by two, form two forts of membranous reeds, whereof the upper part arifes from the two bony and oblong mouths of the internal larynx. The lower part of these reeds is afterwards terminated

C