Popular Science Monthly/Volume 9/August 1876/Voice in Man and in Animals I
|VOICE IN MAN AND IN ANIMALS.|
OF THE PARIS ACADEMY OF SCIENCES.
MAN possesses language, and makes large use of it, while, on the other hand, not even the most intelligent animals have the power of designating objects, or of translating sensations into articulate speech. In this respect the distinction between man and beast is very marked. It has at all times been cited as an evidence of man's exceptional place in Nature. The physiologist, however, discovers an articulate voice in many animals. Some mammals give utterance to vowels and consonants, but the result is only one syllable repeated without variation. Birds, better gifted than the mammals, can sing, and also possess a brief vocabulary: the goldfinch pronounces several words, which it repeats again and again in moments of pleasure. It has a word to express its ill-humor, as also a word for calling attention. In all this we see faint traces of language, notable witnesses of the unity of a phenomenon the gradations of which are wanting.
Some animals live in society, others travel in flocks. In such aggregations there is plainly developed a sort of language adapted for establishing concert of action among the individuals. In building their lodges, how could beavers make a regular division of labor, and so perfectly coordinate their work, if they were unable to understand one another? The marmot, acting as a sentinel, could not warn its fellows of the approach of danger, if it did not possess the power of giving a signal, the meaning of which they understood. When swallows are about to migrate, some of them appear to be concerned about the performance of the periodical voyage some time before the rest: they flock together and utter their call; they flit hither and thither to summon individuals who, in their folly, take no note of the change of temperature. Is it not plain that these birds know how to say, "It is time to he gone?"
But in all probability the language of animals gives expression only to very simple impressions and ideas. But, inasmuch as we do not understand it, we cannot define either its extent or its true character. Some persons have the power of imitating the calls and songs of birds; and birds, in turn, repeat human language, without, however, understanding its sense; it is only very rarely that we can recognize in the phrase uttered by the inhabitant of a cage the expression of a desire. Man and dog, close friends though they are, understand one another only by means of a sort of pantomime. Eventually the dog understands some of the words spoken by his master, and the man. understands some of the vocal expressions of his trusty friend; and this is the highest result of long association. It appears as though, by a supreme will, an insurmountable obstacle had been opposed to all close communication between man and animals.
Apparently those animals whose organization comes nearest to that of man lack both the faculty of producing an ensemble of articulate sounds and the degree of intelligence requisite for attaching to words a strictly determinate meaning. No monkey has ever learned to talk. In our own day the comparative study of specialties of organization and of the life-conditions of living beings has thrown light upon the subject of articulate speech. We may confidently affirm that a creature possessing an instrument or an organ subject to the control of its will comes into the world possessed of an instinct to employ that organ or instrument; guided by intelligence, it will make more or less happy use of it. As individuals differ from one another in the perfection of their vocal organs, so too they differ in the measure of their control of those organs. Natural gifts and judicious exercise afford immense advantages. All men possess a vocal apparatus: for talking or for singing they usually employ it skillfully enough to answer all common demands; while a privileged few produce wonderful effects with the same instrumentalities.
The mechanism of voice deserves to be studied by all. As regards man, we now have very accurate knowledge of the manner in which speech and singing are produced. Means having been found of viewing the play of the different parts of the larynx, physicians intent upon the advancement of the art of healing, physiologists spurred on by the desire of explaining phenomena, singers eager to penetrate the secret of the highest achievements in their art, have all devoted themselves to patient researches. The results of a multitude of investigations have been published, and in this way science has been greatly extended. Dr. Mandl, an observer who had already studied in its minutest details the structure of the respiratory organs, has given the fullest account yet presented of the vocal apparatus in all the phases of its activity. At present he is engaged in studying the phenomena of voice in the larger animals. As for birds, it is to he hoped that soon we shall understand the organic peculiarities in virtue of which they are able to talk or to sing. Doubtless before long we shall discover the relations subsisting between life-conditions, physical powers, and psychological faculties.
In all those communities which have attained a high degree of intellectual culture, the explanation of natural phenomena has ever more or less engaged the attention of the best minds. Among the ancients we observe a manful effort to discover the secret of the human organization. The origin of speech and of song was unquestionably a subject of profound inquiry for them. Galen, the last and the most famous of the ancient physicians, wrote a description of the larynx, and this description is the work of a master who recognizes the high importance of the work he is engaged in. Since the time of the Renaissance anatomists have been studying the minutest details, and physiologists experimenting. Thus everything was ready for new discoveries, so soon as it should be possible to place before the eye the performance of the instrument used by the singer. It would be difficult, without some knowledge of the vocal apparatus, to understand how the sounds are produced, and hence we will briefly describe those portions of the respiratory organs in which the voice is formed.
The trachea, which is the passage for air between the mouth and the lungs, ascends from the chest to the middle region of the neck; it is made up of cartilaginous rings. At its lower extremity it branches out into two tubes, which are divided and subdivided into numerous ramifications: these are the bronchi, which terminate in the lung-cells. At the upper extremity of the trachea is the larynx, appearing like an angular box, and crowning the trachea like the capital on a column. Cartilages connected by ligaments give considerable strength to the walls of the larynx. Internally these walls have a lining of mucous membrane, which forms folds known as the vocal cords, or better, lips. Under the action of special muscles these folds separate from one another, are elongated or shortened, or become tense, and hence the differences of sound. The cartilages are four in number: two on the anterior surface of the box and two on the sides. In advanced age these cartilaginous plates ossify; the suppleness of the larynx is then greatly diminished, and the voice loses the power of modulation which it possessed in the period of youth. One of the cartilages, which has the form of a ring, is much higher behind than in front. This ring, being firmly fixed upon the first ring of the trachea, serves to support the various parts which constitute the larynx. The largest of these parts shields, as it were, the front of the vocal apparatus: it consists of a plate of cartilage bent into a V-shape, with the point of the V turned forward. In women it is less prominent than in men, and it is known as Adam's apple. The lateral cartilages, which spring from the ring-cartilage at the back of the larynx, assume the form of little triangular pyramids with uneven surface. They are slightly curved toward the upper extremity, and support a little horny plate, which in the eyes of the ancient anatomists resembled the snout of a pitcher. The lateral cartilages, being very mobile, play an important part in the emission of the voice.
The larynx is to some extent movable. Being attached to the hyoid or tongue bone by means of a membrane strengthened by ligaments, it is lifted up by the action of muscles extending from the tongue-bone to the external surface of the thyroid cartilage; it is pulled down by the action of muscles which extend from this same cartilage to the sternum. Further, the vocal apparatus is affected by the movements of the pharynx and of the tongue, as also by the respiratory movements. The solid parts of the larynx, being more or less movable, change position under the action of muscles which pass from one to another of them. Bundles of muscular fibre which spring from the annular cartilage (the cricoid) cause the thyroid cartilage to move up and down, and this movement produces tension of the vocal cords. Muscles springing from the cricoid and from the thyroid produce a rotation of the lateral cartilages, and modify the conditions of the cords. Finally, there are bundles of muscular fibre extending from one lateral cartilage to the other; when these contract, the walls of the larynx are brought nearer to each other, and the opening through which the air passes is made narrower.
Internally, the larynx is lined with mucous membrane, which is continuous with the mucous membrane of the mouth. Two pairs of ligaments, extending from the thyroid to the arytenoid, divide the cavity into compartments. The lower portion is limited by an arch formed of thick folds of mucous membrane. The middle portion is distinguished by the presence of folds supported by ligaments. These are the vocal cords, which play the principal part in the act of phonation. The superior cords, which resemble thin bands, occupy both sides. The inferior cords, or true vocal cords, which are very thick, are situated beneath the upper, and extend considerably beyond them toward the median line. They bound the orifice called the glottis. This orifice, which in the state of repose is triangular in shape, varies constantly in form and in dimensions under the influence of respiration and the emission of the voice. This use of the term glottis, which signifies tongue, to designate an orifice, is very curious, and is the result of a strange confusion of ideas. The ancients observed in the larynx "organs resembling the mouth-pieces of ancient flutes, viz., the parts on the right and left, which meet and regulate the passage of the air." Later, the term denoting the folds which bound the orifice was used to designate the orifice itself. This error has been confirmed by the usage of centuries, but yet it is better to give, as Mandl does, to the space between the vocal lips, the name of glottic orifice, or orifice of the glottis. The superior portion of the larynx is the vestibule communicating directly with the back part of the mouth. Above the entrance to the vestibule and back of the tongue, a fibrocartilaginous plate, the epiglottis, defends the passage. Under ordinary circumstances, the epiglottis stands vertical, presenting no obstacle to the free passage of air in both directions. When depressed, it covers the opening. Every one, from personal experience, is familiar with the painful sensation produced by the entrance of liquids or solids into the respiratory passages. Apparently the epiglottis closes up this passage during the act of swallowing, but on this point we have no certainty; we cannot observe the act of deglutition, and we know that the vocal cords may be moistened by liquids without causing inconvenience.
Like every other organ, the larynx presents considerable individual differences. A good development of the larynx indicates a strong, deep voice. In childhood this apparatus undergoes very little change, but at the period of adolescence it grows very rapidly, the effect being an alteration of the voice, very notable in boys, but inconsiderable in girls. In all cases, without regard to stature, the larynx is smaller in women than in men. Its angles are less salient, its muscles weaker, its cartilages thinner, and more supple: the sharp notes of the instrument are the evidences of these peculiarities of conformation. Though our general knowledge of the vocal organs is very positive, nevertheless we are unable to determine the characters of the voice by simply examining the larynx, for it is impossible to compare in all their details those instruments whose good or bad qualities are known.
The vocal apparatus is perfected by the addition of the cavities which produce resonance, viz., the pharynx, the mouth, and the nasal fossæ. The pharyngeal cavity, into which open the œsophagus and the larynx, is continuous with the buccal cavity, a hollow box admirably adapted for articulation. Its shape and size are extremely variable. The cheeks constitute walls which can be compressed or dilated with the slightest effort; the lips, which bound the anterior opening, are perfectly mobile; the tongue can be moved in every direction; in the rear, the velum palati, or soft palate, suspended from the palatal arch, is supple and contractile. This veil of the palate is simply a fold of mucous membrane, separating the buccal from the pharyngeal cavity; it also extends to the nasal fossæ, which it closes; it terminates in an appendage called the uvula. When the velum palati, or soft palate, does not discharge its functions properly, the voice assumes a specially disagreeable character—it becomes nasal. The two rows of teeth act a part in producing speech; a breach once made in this rampart, the pronunciation becomes defective, the air escapes through the unguarded space, and the result is a hissing sound.
The plan of action of the whole vocal apparatus being under investigation, in the absence of the means of direct observation, recourse has been had to endless stratagems, in order to have a glimpse of the play of the organs and to explain the mechanism of voice-production. It has been a struggle with incredible difficulties, in which the human mind, though it has not won a complete victory, has nevertheless acquitted itself with honor. Some of the investigators succeeded in forming theories which are not very far from the truth, but these theories are now only the monuments of a period whose science is antiquated.
Galen, in comparing the organ of voice to a flute with double mouth-piece, referred the production of the sound to the vocal cords. Fabrizio d'Acquapendente, the famous professor of the University of Padua, held that the dilatation and contraction of the glottic orifice determined whether sounds shall be grave or acute. Dodart, a member of the old Académie des Sciences, held that the tone depends upon the greater or less number of vibrations of the vocal cords. Ferrein, one of the famous anatomists of the eighteenth century, conceived the idea of causing the larynx of a dead body to produce sounds by blowing through the trachea. He affirms that the lips of the glottis vibrate and emit sound like the strings of a violin. Magendie made experiments upon living animals; having laid bare the glottis, he saw the vocal cords vibrating when the animal uttered a cry. Savart, famed for his researches in acoustics, compared man's vocal apparatus to an organ-pipe. Lehfeld, a German author, laid stress upon the special effects of the cords, as vibrating through their entire substance, or only at their free edges. Cagniard de Latour constructed artificial larynges with mouth-pieces of membrane. John Müller, the physiologist, after a series of diversified researches, was of the opinion that "the vocal organ is a mouth-piece consisting of two lips, and that the vibrations of these is the chief cause of the sound—the pitch being determined by the width and length of the orifice of the glottis." Longet, who made numerous experiments on the actions of the muscles of the vocal organ, threw new light upon the conditions modifying the vibrations. In short, the result of all these researches, made by investigators who never had seen the larynx of a living man, was firmly to establish one point, namely, that the voice is formed in the glottis. The proofs of this are conclusive, for, if an opening be made in the trachea, the voice ceases; it reappears when we close the opening again; it persists though the superior parts of the larynx be rent and torn; but it is destroyed by lesion of the nerves of the little muscles which alter the form of the glottis and stretch the vocal cords.
But alongside of these undisputed facts there were a number of undecided questions which stimulated to further research. Some investigators were continually meditating on methods of viewing the larynx in normal action. Toward the close of the last century mirrors were first employed for this purpose, but the earliest attempts were unsuccessful. For fifty years all efforts of this kind proved abortive, and the thought of examining the interior of a living larynx was coming to be regarded as an illusion. Suddenly, as by an inspiration, the solution of the problem occurred to the mind of Manuel Garcia. Ignorant of the labors of others who had endeavored to obtain a view of the vocal apparatus, Garcia conceived the idea of observing his own vocal organs in the act of singing. Taking a small mirror attached to the end of a long rod, he placed it beneath the uvula, and then, illuminating with a beam of sunlight another mirror which he held in his hand, he had a full view of his own larynx. Thus was discovered the true method of investigation. In 1855 Garcia communicated to the London Royal Society the result of his observations on the living larynx.
When a new mode of research is discovered, the first investigators to take hold of it are those who have little or no prepossessions of their own. They perceive that, by varying the application of the process, notable results may be attained without much labor or ability. Garcia's process called forth on many sides much enthusiastic zeal. This was the case especially at Vienna, but the results fell short of the anticipations. The caprices of the sun's light and the defects of artificial light were such as to discourage the observers. In order to succeed, the means of illumination had to be improved at any cost. Garcia had used for a reflector a plane mirror; J. Czermak, Professor of Physiology at Pesth, finding his pattern in the instrument used for inspecting the eye, the ophthalmoscope, employed a concave mirror, which concentrates the light. The feasibility of studying man's vocal apparatus by means of the laryngoscope was now insured. Still, for a long time afterward, experimenters busied themselves with devising contrivances for increasing the intensity of the light by combinations of glass lenses.
Czermak, who by long practice had acquired great skill in the manipulation of his own larynx, visited the principal cities of Germany, taking with him a good instrument. His demonstrations were witnessed with profound interest by physicians and physiologists. In 1860 he came to Paris, and astonished many of the members of our learned societies. He exhibited not only the whole of his own larynx, but also the interior of his trachea down to the bifurcation—a sight well calculated to cause astonishment when one sees it for the first time. The vocal organ cannot be examined with the same facility in all persons, and some practice is needed for experimenting successfully. Dr. Mandl and Dr. Krishaber possess an extraordinary power of controlling the various movements of the larynx. After repeated experiments we now fully understand the functions of the vocal organs in speaking and in singing. The studies of Helmholtz upon the formation of sounds have thrown new light upon the phenomena of voice.
The notes of an organ, when heard beneath the arched roof of a cathedral, produce a profound impression. Inasmuch as no other kind of music so closely resembles the human voice, we can fancy ourselves communing with the thoughts and feelings of the human soul. We naturally compare the organ to man's vocal apparatus. The organ has a bellows, we have lungs; in the organ is a "sound-board" the trachea performs the same function; the vibrating tongue of the organ has its counterpart in our vocal cords; and the pharynx and the mouth answer to the resonating cavities of the organ. Yet the natural instrument is immensely superior to the artificial one. In the organ there must be a number of pipes to produce the different sounds; in the natural instrument there is only one pipe for both speech and song, but it is a wonderful pipe, being susceptible of endless modifications. It has a double vibrating spring and a resonator. The glottis is the vibrating spring or tongue, and, according as the air-passage is more or less narrowed, and the vocal cords more or less tense and vibrant, the sounds emitted are either grave or sharp. The mouth forms the resonator; the cavity of the mouth is susceptible of almost endless modifications, producing an infinite diversity of sounds.
Our various senses are each affected by a special order of impressions; the organ of hearing takes note of sounds, which are propagated by concussions of the air, by vibrations. When these vibrations are continuous, regular, isochronous, they constitute a musical sound; when irregular, the result is noise. Sounds possess very definite characters, as intensity, pitch, timbre. Intensity depends upon the amplitude of the vibrations, which travel in the form of concentric spheres from the starting-point, as the waves caused by a pebble dropped into water are diffused in the form of concentric circles. Amplitude is always the result of the force of the primary shock. The pitch of a sound is determined by the number of vibrations occurring in the space of one second: when the vibrations are few, the sound is grave; when very numerous, it is sharp. In a word, the shorter the duration of each vibration, the higher the pitch of the sound. Timbre means quality of voice. We distinguish voices by their timbre; we hear some one speaking, and recognize who it is without seeing him; or we hear a strain of music, with several sounds of the same pitch, but we readily by the timbre distinguish from one another the violin, the flute, the clarionet. The differences are the result of the different forms of the vibrations; this may be demonstrated by experiment. Whether we consider the movements of a pendulum or of a tuning-fork, in every case the vibration, when traced automatically, gives a characteristic line for each variety of timbre. If by means of the ear, rendered highly sensitive by long practice, we study to distinguish the different forms of the waves, we recognize in addition to the fundamental sound other higher sounds, the harmonics. Helmholtz's resonators aid the analysis by the ear. The resonator is a little hollow sphere with two open tubes, one of them conical, so as to fit into the auditory passage. The fundamental sound, which is much deeper than the other sounds, is thus considerably reënforced. In like manner, with the aid of proper resonators, it is easy to hear the harmonics of the human voice. Helmholtz ascribes the diversity of timbres to the intensity of the harmonics. Physiologists hold that there exist other causes, as yet not ascertainable.
In the state of rest, when respiration is performed without effort and with regularity, the vocal cords are almost motionless; during the alternations of inspiration and expiration, the orifice of the glottis does not alter its form. After a cry has been uttered, there occurs a deep inspiration, and then the vocal cords diverge, widening the aperture. When expiration is suspended or performed slowly, the orifice closes more or less. At the moment of emitting a sound, the lateral cartilages of the larynx are brought near to one another, and the vocal cords are suddenly made tense and applied closely to each other in their anterior portion, or even throughout their entire length; the passage of air is thus intercepted. Instantly the orifice opens again, and the air in passing between the vibrating vocal cords is itself thrown into vibrations, and sound is the result. These operations are performed gently or forcibly according to circumstances. Here we have the "glottic sound," as it is called by Mandl; isolated, it is inaudible, but it reaches our ear only after it has traversed the pharynx and the mouth; the vibrations of the air modify it. Every one has remarked the change produced in sounds by their passing through a tube or the like; for instance, when we hear a voice coming from the bottom of a well. Hence the voice is formed by the combination of the sounds of the glottis and of the cavities lying above the larynx: when these cavities are passive, the voice is inarticulate; when they undergo certain changes of form, the voice becomes articulate.
The pharynx and the mouth, which serve as a resonating box, produce sounds whenever the air they contain is made to vibrate by the current from the lungs or from any other source. That this is the case is shown by certain decisive and very interesting experiments. On opening the mouth and adjusting the lips for the pronunciation of a given vowel (though without uttering the slightest sound), the vowel may be rendered sonorous by placing in front of the mouth a vibrating tuning-fork. This method was first applied by Helmholtz. The same result may be obtained by bringing in front of the open mouth, through a tube with narrow terminal orifice, a current of air from a pair of bellows. This plan originated with M. König. Thus it is seen that the various sounds known as vowels depend simply on the form of the resonating cavities, the pharynx and the mouth. When these cavities alone are in action, the voice is aphonic, whispering; it is sonorous when the vocal cords vibrate. For a long time it was held by physiologists that vowels pronounced even in a whisper come from the glottis; precise information concerning these phenomena is of very recent date.
The number of vowels is generally restricted to five, six, or seven; these may be regarded as natural types, being found in nearly all languages. But, in addition to them, there are intermediate vowels, and a multitude of vowel combinations, so great is the power of modification possessed by the buccal cavity. Then there are nasal intonations (very abundant in the French language) produced by depressing the velum palati. A language might consist only of vowels, says Max Müller, and indeed this is very nearly the case with some of the Polynesian dialects.
Most languages possess aspirates of more or less harshness. In French they are very few and weak, but in German they are frequent and strong, while in Arabic they are specially forcible. Aspiration requires the action of the glottis; the orifice is reduced for an instant, and the air, arrested by this obstacle, in issuing through the narrow slit, produces a sound of something brushing against the vocal cords. The aspirate is sometimes sonorous in the Semitic languages. The guttural sounds of the Arabs used to be the subject of grave discussions among linguists, but Czermak put an end to these controversies. That learned physiologist, having fallen in with an Arab, availed himself of the opportunity to examine with the laryngoscope an organ capable of producing a sonorous aspirate. The whole matter was now plain: it was found that, while the epiglottis was depressed, the vocal cords were in close contact; the orifice being thus absolutely closed, the current of air driven against the roof produces a vibration beneath the glottis, in the fissure of the larynx.
The sounds produced in the buccal cavity are broken up on meeting obstacles: thus are formed the sounds known as consonants. In setting up these obstacles, the tongue, the teeth, the lips, the soft palate, play respectively a more or less important part. We readily distinguish the labials, the linguals, the dentals, the nasals. No classification, however, will stand a rigid analysis; the simultaneous play of the teeth, tongue, lips, and soft palate, and the somewhat doubtful character of some sounds, render all classifications more or less arbitrary.
Among the consonants are the sounds of puffing, hissing, trilling, and these are pronounced without the aid of vowels. The labials are formed mainly by the movement of the lips—the easiest movement of all those concerned in the utterance of speech. Accordingly as the lips are closed tightly or loosely, two distinct letters are pronounced; if the closure is imperfect, a third letter is produced. There are two letters, m and n, which it is impossible to pronounce with the soft palate depressed, so as to close the nasal passages. Czermak introduced water into his nostrils, and then tried to pronounce these two consonants; the water was forced out by the passage of the air. The sound of the dentals is produced by a strong pressure of the tongue usually against the teeth, which, however, are not indispensable. The gutturals are pronounced by bringing the tongue back against the palate.
All these consonants may be classed, according to the character of the sound, as either surds or explosives. When the external air remains in communication with the air expired, notwithstanding the obstacle set up for articulation, the consonant may be sustained during the continuance of the expiration. Where there is no communication, the duration of the sound is restricted to the instant in which the obstacle is removed, and the result is a slight explosion of the air. This is shown conclusively when we precede a consonant with a vowel, and the same experiment serves clearly to show the distinction between hard and soft explosives. In pronouncing the former the glottic orifice is narrow, the current of air is feeble, and the sound persists for a moment after the mouth has opened; in the other case, the glottis allows the passage of a stronger current of air, and the sound has no perceptible duration.
Certain consonants are in English called trills; they are produced by the interruption of the breath at regular intervals, by vibrations of the soft palate and the extremity of the tongue. In the soft trill, the edges of the tongue produce simple oscillations of the air, but in the harsh trill, the vibrations produced at once by the palate and the tip of the tongue become intense. Finally, there are certain sounds of frequent occurrence in English, German, and the Slavonic languages; these are produced by an expiration differing from one another according to the obstacles opposed by the tongue, the teeth, and the lips.
It has been demonstrated that the sounds of speech are formed in the buccal cavity, by processes which vary within very narrow limits. Authors who have studied in their own persons the pronunciation of the vowels and consonants describe with great minuteness the positions assumed by the lips, the tongue, the soft palate, under all circumstances, and give drawings which show the various operations we perform while articulating letters and syllables. These observations possess great interest; but yet the rules thence derived are not so rigorously true as to be indisputable. As Mandl observes, sounds that are nearly identical are produced with different positions of the organs of speech. If a person has lost all his teeth, he modifies the play of the lips and tongue, and so contrives to speak intelligibly. The voices of persons we know can be imitated so that the deception shall be perfect. By changing the timbre, the voice is made to sound as though it came from a cavern; this is the ventriloquist's art. Persons who had had the misfortune to lose a considerable portion of their tongue, have been able to converse, though it is not affirmed that hearing them speak would be a pleasure. Some birds find it possible to utter sounds which with us require the use of the lips. In a word, there is nothing absolute in the acts which produce speech, though in general the same organs do not differ very much in their mode of procuring the same results, as may be shown from the fact that congenital deaf-mutes who have learned to speak interpret the movements of the mouth with infallible certainty; they see the speech of the interlocutor. This proves that our modes of articulation present only shades of difference.
The phenomenon of deaf-mutes capable of speech has long been esteemed a marvel. In the middle ages there was one instance of this, the credit of which is due to the patience and skill of Beverley, Archbishop of York. In the sixteenth century, the universal scholar, Jerome Cardan, discussed the possibility of teaching the use of the voice to congenital mutes. About the same period, the Spanish monk Pedro de Ponce was, according to an epitaph, famous throughout the whole world for his power of causing mutes to speak. He had for his pupils two brothers and one sister of Pedro de Velasco, and the son of Gaspar de Guerra, Governor of Aragon. Some time later, Juan Pablo Bonet, in a work which is the oldest known upon this subject, treated of the art of giving speech to the dumb. In England, Holland, and Germany, this art was reduced to practice with more or less favorable results; instances of success were few and far between. About the year 1732, a young Israelite, who had come to France from Estremadura, being touched by the unhappy lot of a woman whom he loved, resolved to devote himself to the instruction of deaf-mutes. His name was Jacob Rodrigues Pereira. At La Rochelle, a boy thirteen years of age was brought to him; soon the lad was able to speak, so as to astonish all. The result was noised through the city; one of the grands fermiers had a deaf-mute son, whom Pereira undertook to instruct. After sixteen months of study, he presented his pupil to the Académie des Sciences. The assembly was delighted. Several of the members undertook to examine the case thoroughly, and on July 9, 1749, Buffon reported that the lad had answered questions "both in writing and by word of mouth." At the court of Louis XV. this marvel excited general admiration. The Duke de Chaulnes had a godson that was deaf, a boy of about twelve years; him he placed under the care of Pereira. This pupil, Saboureux de Fontenay, who in after-times attained to some celebrity, was very intelligent, and quickly improved under instruction. On being exhibited at the Académie des Sciences, and there tested in various exercises, he occasioned no little surprise. The official report concludes by stating that "M. Pereira possesses a singular gift of teaching congenital mutes to speak and read."
Pensioned by the king, and honored with marks of esteem by illustrious personages, Pereira continued his labors. He gave the power of speech to a large number of mutes, but he kept his method of education secret. The memory of this brilliant success had been wellnigh effaced, when the Abbe de l'Épée won the favor of all classes of society by giving to the deaf a sign-language. Pereira left behind him pupils who justly believed that they did honor to their master by making public the secret of their instruction; some of these scattered notes have been collected. It has required only a little research to discover the forgotten method. The teaching of deaf-mutes to speak was again brought into practice, and at Geneva M. Magnat was very successful in carrying out this system. He visited Paris, accompanied by some of his pupils, who, though utterly deaf, conversed with wonderful ease. Some grandsons and great-grandsons of Jacob Rodrigues Pereira, on witnessing the renewal of the wonders performed by their ancestor, founded at Paris an institution for educating mutes. In this establishment, children of various ages, about thirty in number, afford matter for curious observations upon the phenomenon of voice and the articulation of language.
A person who is deaf from birth is also absolutely dumb, until he is trained to the use of speech; he utters no cry. His lips and tongue are motionless; his mouth remains shut, his larynx is in a state of unbroken repose; he breathes only through the nostrils. When first the effort is made to have him pronounce a letter written on the black-board, it appears to be simply impossible for him to produce any sound. The instructor shows the young mute how to open the mouth, and how to hold the tongue and the lips. He places the child's hand upon his own larynx, so that it may feel the movement necessary to be performed. In the beginning, the simple expulsion of the breath is difficult, but, after repeated exercise, there is a sort of stifled articulation; later, with some difficulty, a clear sound is obtained. In this way the deaf-mute learns to pronounce all the vowels and consonants. It needs but a short time to acquire the pronunciation of the labials. Longer practice is needed in order to learn the play of the tongue, and the proper mode of emitting the breath in articulating those consonants which call for only a slight intervention of the lips. Having learned the alphabet, the mute begins to pronounce syllables and phrases written on the blackboard. Finally, he speaks, and is understood. He writes from dictation, with his eyes fixed upon the person who addresses him questions, and makes his answers confidently.
- Translated from the French by J. Fitzgerald, A. M.
- "Traité du Larynx et du Pharynx," 1872; "Hygiène de la Voix parlée et chantée," 1876.
- The ring-cartilage is the cricoid cartilage of the anatomists; the V-shaped cartilage is the thyroid; the lateral cartilages are the right and left arytenoids; and the little plate they bear, the cartilages of Santorini.
- On each side, between the superior and inferior vocal cords, occurs a large cavity. These cavities are known as Morgagni's ventricles.
- "Observations on the Human Voice," "Proceedings of the Royal Society of London," vol. vii.
- The different kinds of instruments are described in Mandl's work, "Traité du Larynx;" also, in the article, "Laryngoscope," by Dr. Krishaber, in "Dictionnaire Encyclopédique des Sciences Médicales."
- When we pronounce the vowels a, e, i (pronounced ah, eh, ee), the vertical diameter of the pharyngo-buccal cavity is diminished, while its transverse diameter is increased; it is exactly the contrary with the vowels o, ou, and u (pronounced oh, oo, ü).
- It is the aïn of the Arabic.
- f, s, r.
- b, p, v.
- z, zh, v, s.
- b, p, d, t, g (hard), k, x.
- b, d, gh, as contrasted with p, t, k.
- l and r.
- sh and th in English; sch in German; tch in Russian.
- See Ernst Brücke, "Grundzüge der Physiologie und Systematik der Spracblaute für Linguisten und Taubstummenlehrer," Vienna, 1855; Max Müller, "Lectures on the Science of Language;" Johann Czermak, "Populäre physiologische Vorträge," Vienna, 1869, etc.
- "Abecedario demonstrativo: Reduccion de las letras y arte para enseñar a hablar los Mudos," 1620.
- See an interesting sketch by M. Félix Hément, entitled "Jacob Rodrigues Pereire, premier instituteur des sourds-muets en France," 1875.
- The institution founded by the Messrs. Pereire, at 94 Avenue Villars, Paris, is directed by M. Magnat, author of the "Cours d'articulation, pour l'enseignement de la parole articulée aux sourds-muets," 1874.