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conditions, a full chest note is emitted; but if they do not meet in their entire length, either a posterior or anterior portion of them remaining apart, the sound is no longer full, but feeble and shrill: the note emitted is what the stringed instrument player calls a harmonic, and what the singer calls a falsetto, or head note. The violinist who would bring out a harmonic, so touches a string that, instead of making it vibrate as a whole, he divides it into segments, each of which vibrates by itself, and emits the note due to its short length, instead of that which the full length of the string would yield. The same sort of thing seems to be done by the falsetto singer: the adept can at will shorten his vocal cords so as to pass instantly from any note to its harmonic. The muscular process by which this transition is effected is not clearly made out, so that it cannot be determined whether all singers are alike gifted with powers of head-singing equal to the Tyrolese, or whether Alpine melody grew out of peculiar capabilities of Alpine throats." I am indebted to Dr. Gordon Holmes for the subjoined illustration from his "Vocal Physiology," of the vocal cords in the act of producing the falsetto.

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I have now, I think, given you a sufficiently full description of the vocal cords and the functions they perform; and to witness their movements in the act of vocalisation by means of the laryngoscope, as I have done repeatedly (and strongly advise you to do if you ever have the opportunity), is certainly one of the most wonderful and interesting sights that can be imagined.

I mentioned just now the rima glottidis, or glottis, as it is usually called, and told you it is the narrow interval or chink between the vocal cords. Its extent is greater than that of the cords, for it reaches across the larynx. It measures from before backwards usually nearly an inch, and across at the base, when dilated, about one-third of an inch in men, but in women and boys less. During inspiration the space is larger than in expiration. It forms two changes with its dilatation. In a state of rest the interval resembles in shape a spear-head, with the shaft placed backwards; when dilated it is triangular in form, the base of the interval being behind. It is provided with wonderfully delicate muscles, by which it is contracted or expanded, and assumes, according

to circumstances, a great variety of shapes. At that period of life when the boy becomes the young man, and the girl becomes the young woman, a marked change takes place in the size of the glottis, as well as in the character of the tone produced by the vocal organs. Usually, in less than a year at this period of life, the opening of the glottis increases in man in the proportion of five to ten, its extent being doubled both in length and breadth. In woman the change is not so remarkable in character; her glottis usually increases in the proportion only of about five to seven, which at once accounts for the much greater change which takes place at this time in the voice of man. As the glottis enlarges with the progress of years and the continual practice, on sound physiological principles, of public speaking, or reading aloud, the voice becomes stronger, fuller, and deeper. In woman, the voice always remains comparatively weaker and higher in pitch, her glottis being, according to the eminent physiologist, Richerand, a third smaller than in man. Sometimes we meet with instances of men retaining in mature life the effeminate, cracked, falsetto, disagreeable voice which marked the period of puberty. In almost every case where there is no organic defect or malformation, a single course of lessons under a good elocution master, acquainted with the anatomy and physiology of the organs of speech, will remove the evil. The epiglottis is the uppermost of the five elastic cartilages forming the larynx, and its office is to direct. the expired sound, and to open and shut like a valve the aperture of the exterior glottis.

Such, then, is a brief description of the larynx and its functions, and these are manifestly so highly important in connection with the production of voice, that the necessity is apparent to all, that care should be taken by every one, but especially by the public speaker or reader, to avoid contracting bad habits in speaking or reading, which may in any way injure so wonderful and delicate an organ.

I have now to speak of what I may term the influence of the auxiliary organs on the voice. The variation of the length of the trachea, as the prefixed tube, seems to have but little influence on the note produced in the larynx. It is admitted, however, that the elongation of the superadded tube above the glottis facilitates, by the descent of the larynx, the production of low notes, while its shortening, by the ascent of the larynx, favours the production of higher notes.

There are two little cavities, readily seen in many persons as dark lines on the outer margin of each vocal cord, between the latter and the regulators of the glottis. These are called the ventricles of the larynx. Sir G. D. Gibb says it is a curious fact that in most negroes a view can be obtained of their interior, from the obliquity of their position in that race. The chief office assigned to these cavities is to afford sufficient space for the vibration of the vocal cords. The ventricular sacs, moreover, appear to supply the vocal cords with the requisite amount of moisture while they are vibrating. The French physiologist, Savart, maintained that the air may vibrate in the ventricles, independently, and may produce sounds in such cases, when the other elastic parts are incapable of sufficient tension.

Let me now ask your attention to this diagram, to which I shall have to refer not merely in this Lecture, but when I come to speak of articulation and impediments of speech. (Fig. 9.)

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Median section of the head; F, frontal bone; S, frontal sinus; B, bone of the nose; C, cartilage of the nose; V, external nostril; U, upper spongy bone; M, middle spongy bone; L, lower spongy bone; 0, occipital bone; V, vertebræ ; P, the spinous processes; I to 12, the cranial nerves; 13, the spinal cord; 14, superior maxillary bone; 15, hard palate; 16, soft palate; 17, uvula; 18, tonsil; 19, tongue; 20, frænum; 21, genio-glossus; 22, genio-hyoideus; 23, hyoid bone; 24, palato-pharyngeus; 25, epiglottis; 26, hyo-epiglottic ligament; 27, hyo-thyroid ligament; 28, supe rior ligament of the glottis; 29, arytenoid cartilage; 30, inferior ligament of vocal cord; 31, thyroid cartilage; 32, cricoid cartilage; 33 33, incisors; 34 34, lips.

It represents, you see, a sectional view of the human head, from the central line at the top of the skull to where the larynx terminates. Now, much of the resonant quality of the voice is influenced, not merely by the state and size of these ventricles of the larynx, of which I have just spoken, but by the dimensions and condition of the fauces, the oral and nasal cavities, and the development of those hollows in the long part of the forehead, marked S, and which are called the frontal sinuses. The eminent physiologist, Professor Owen, is of opinion that that want

of resonance for which the voices of the natives of Australia are so remarkable, is most probably owing to the fact that the frontal sinus is not fully developed in that race. It may thus be considered that the parts above the glottis, in regard to the production of these secondary vibrations of sound which we term resonance of the voice, serve (to use the comparison of the late Dr. Hunt) the office of a short. speaking-tube.

Much also depends on the proper expansion and position of the chest, for when this is rightly carried out, not only can you then hear the vibrations of the voice in singing or speaking, but if you place your hand on the chest, you can actually feel that the whole cavity of the thorax is resounding within.

The influence of the epiglottis, too, must not be passed over unnoticed. When it is pressed down, so as to cover the larynx, vocal sounds are rendered deeper and rather duller. Müller states, "in uttering deep notes, we evidently employ the glottis in this way; such, at least, seems to me the object of the depression of the tongue, when, endeavouring to produce very deep notes, we press down the head."

An eminent Italian physiologist, Bennati, remarks that the soft palate rises and assumes an arched shape in the formation of low notes, and sinks in those of higher notes.

The uvula keeps its normal position in the lower notes of the voice, but nearly disappears from sight in the production of the highest notes. The importance of this organ in regard to the tone of the voice is very considerable; for if it be of unusual size or deficient in contraction power, the purity and power of the voice are greatly impaired. According to the same authority, the tonsils also swell and approach each other when high notes are being produced.*

Dr. Carpenter, to whom we are indebted for one of the best works on mental physiology, as well as physiology generally, when treating in his "Principles of Physiology" of the degree of precision with which the muscular contraction of the glottis can be adapted to produce a designed effect, says, "The natural compass of the voice in most persons who have cultivated the vocal organs, may be stated at about two octaves or twenty-four semitones. Within each semitone, a singer of capability could produce at least ten distinct intervals; so that the total number, 240, is a very moderate estimate. There must, therefore, be 240 different states of tension of the vocal cords producible by the will; and, as the whole variation in the length of the cords is not more than one-fifth of an inch, even in man, the variation required to pass from one interval to another, will not be more than 100th of an inch. And yet this estimate is much below that which might be made from the performance of a practised vocalist. It is said that the celebrated Madame Mara was able to sound 100 different intervals between each tone. The com

Since the above was written, I have had the privilege of seeing a most ingenious working model of the larynx, just designed (1875) by Mr. Edmund J. Spitta, late demonstrator of anatomy at the school of St. George's Hospital, illustrating his view of its various movements, and constructed by Mr. Hawkesley. A full description of it will be found in the Appendix.

pass of her voice was at least three octaves or twenty-one tones; thus the total number of intervals was 2100, all compressed within an extreme variation of one-eighth of an inch; so that it might be said that she was able to determine the contractions of her vocal muscles to nearly the seventeen-thousandth part of an inch."

The late Dr. Hunt stated in 1859 that some physiologists have endeavoured to calculate the changes of which the human organ of voice is capable, on the assumption that the number of changes must at least equal the number of muscles employed. Considering that at least seven pair of muscles belong to the larynx, and that they can act singly, or in pairs, or in combination with the whole, or with part of the next, they are, according to Dr. Barclay's estimate, capable of producing upwards of sixteen thousand different movements. When to the proper muscles of the larynx are added those attached to the cartilages and hyoid bone, which may act independently, or in co-operation with those of the larynx, the estimate would have to be very largely increased. But as all the respiratory muscles have directly or indirectly an influence in the production of the voice, the changes which they are capable of producing in the relative position of the vocal organs will scarcely admit even of an approximate calculation. The number of movements of which the vocal apparatus is susceptible, and the variety of tone which it can produce, may indeed be said to be beyond conception.

To students who may be desirous of investigating more fully and minutely the nature and action of the mechanism of the larynx in producing all the various elements of voice and speech, I recommend very strongly the admirable translation by Mr. Lennox Browne of the elaborate and interesting work by the eminent physician, Dr. G. J. Witkowski, of Paris, so fully and copiously illustrated, that no less than one hundred and forty-nine different parts of the throat and tongue are pictorially brought before the eye of the reader, and fully described by the author, and to which the translator has added some most valuable and original notes and observations.*

Before I leave the subject of the vocal organs, it may not be uninteresting to you, especially in these days, when Professor Huxley's Lectures, Darwin's "Origin of Species," "Descent of Man," and other works, have drawn popular as well as scientific attention so much to the various points of resemblance and difference between the anatomy and physiology of man and animals, if I touch briefly on the voice of animals, and the mode by which it is produced. In all the mammalia, the general structure of the larynx resembles that of man. The power and peculiar character of the cries or sounds made by various animals, such as the roar of the lion, barking of the dog, lowing of cattle, or bleating of sheep, &c., depend on different degrees of development of the vocal cords, and some peculiarity of structure in the larynx and other organs; for instance, the "howling" or "preacher monkey," of South America, though by no means large in size, yet possesses a voice which is capable of being heard at a distance of more than two miles. This extraordinary intensity and power of voice is * Published, price 10s. 6d., by Baillière, Tindal, & Cox, King William Street.

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