The only part of the Mouth which requires a particular description is the soft palate. This is a movable partition by means of which either the mouth or the nose can be completely separated from the throat. If the nose is to be shut off from the throat the soft palate is raised, and pressed against the back of the pharynx. If the mouth is to be shut off the soft palate is lowered, and rests closely upon the back of the tongue. This partition plays a most important part in vocalization. In the formation of all pure vowel sounds it is raised, thereby closing the nasal cavities, and it has been found that the closure is loosest for "ah" (as in "father") and tightest for "e" (as in "bee"), the intermediate vowels being "a" (as in "name"), "oh" and "oo" (as in "food"). This has been clearly shown by Czermak in the following manner. Lying down on his back, he had the nasal cavities filled with tepid water. He then uttered the various vowel sounds, and ascertained from the quantity of water required to force open the closure formed by the soft palate the degree of tightness for each vowel. He afterwards constructed a very ingenious little apparatus, by means of which, in one of his lectures, he demonstrated this fact to his audience. It will be easily understood from the above explanation that, if the closure of the nasal cavities is sufficiently imperfect to allow any considerable amount of air to pass through the nose, the result will be a nasal tone.
I am aware that the very opposite is taught by some. There are those who maintain that nasal tone arises from the air not being able to get through the nose. I am even informed that in some parts of England where nasal tone seems to be a general affliction, it is the practice of teachers of singing to cause their pupils to bathe their noses in hot water in order to relax the muscles which are supposed by their contraction to produce nasal tone. I would, however, in support of my statement, draw attention to the following indisputable facts:—(1) It is quite possible to completely close the nostrils, and yet to produce pure vocal tone. (2) Persons who are either partly or entirely without the soft palate can under no circumstances utter a single sound without the most pronounced nasal quality. It seems to me that these facts sufficiently speak for themselves; but if any of my readers are not convinced by them, let them try this experiment: Take a thin mirror and hold it flat against the upper lip, with the glass upwards. Now sing a pure vocal tone, and the mirror will remain perfectly bright. Sing, on the contrary, with nasal quality, and the mirror will at once be completely dimmed. This shows conclusively that nasal sound is produced by singing through the nose, and this cannot be done without lowering the soft palate. Teachers of singing know well enough that guttural tone is caused by the obstinate arching up of the tongue, and if they understand their business they eventually succeed in teaching a pupil labouring under this disadvantage to get perfect control over his tongue. But nobody thinks of the soft palate, though that can be brought under subjection just as well as the tongue. Let singing masters see to it, and young ladies will no longer be laughed at for having to put their noses into hot water before charming their friends with a song.
It now only remains to be added that the interior of the windpipe and of the voicebox, as well as that of the throat, the mouth, and the nose, is lined with a thin mucous membrane of a pinkish colour. This concludes my description of the Vocal Organ as a musical instrument.
DIFFERENCES OF THE VOICEBOX, OR
LARYNX, IN CHILDREN, WOMEN,
AND MEN.
The voicebox of a newly-born baby is about one-third the size of that of a grown woman. It is therefore rather large in proportion to other parts of the body, with the exception of the head, which comparatively is larger still. The horizontal outline of the shield cartilage is a very gentle curve, and the upper horns are short, in consequence of which the voicebox is close to the tongue. The wedges, according to Merkel, are strongly developed; the vocal ligaments are short and thick, and the pockets deep. Up to the third year the voicebox grows very considerably, but no particular alterations take place from that time to the period of puberty, which generally occurs at the age of 14 or 15, rather earlier in girls than in boys. This period of change lasts from six to twelve months, or sometimes even two or three years. During this time the vocal organs undergo a marked change. In boys, the angle at which the two plates of the shield meet becomes more and more acute, and the length of the vocal ligaments increases only in the proportion of five to ten. In girls, on the other hand, the horizontal outline of the shield does not lose its evenness, and the length of the vocal ligaments increases only in the proportion of five to seven. The cartilages would seem, especially in boys, to grow more rapidly than the muscles, so that the slowly-growing muscles do not, at first, control the newly-developed cartilages. This accounts for the unmanageable state of the voice at this period. The changes which take place in the female voicebox are very imperceptible, so that they do not materially affect the character of the voice. In the male voicebox, on the contrary, the alterations are very marked, and the result is that the high voice of the boy is changed into the tenor or the bass of the man. While, therefore, before the period of puberty the voicebox is materially the same in both sexes, there are, afterwards, considerable differences noticeable, not only with regard to size, but also with regard to shape. This seems, indeed, sufficiently obvious, and any one can see it by simply comparing the outside of the throat of a man with that of a woman.
Nevertheless we are told by Mr. Lunn[L] that "Anatomy teaches us that there is no difference between the male and female larynx save in size;" and by Dr. Garrett (on page 13 of the book quoted before) that "The male larynx does not differ anatomically in the least from that of the female, except in size."
My readers may judge for themselves whether these statements are borne out by facts or not.
It must further be observed that the whole upper part of the shield in the female voicebox is less developed than in the male. The upper horns are short, so that the voicebox is more closely attached to the tongue-bone, and its position in the throat is altogether higher in woman than in man. To show more clearly still the difference in the proportions of the male and the female voicebox, I give below some average measurements (taken from Luschka's great work on the Larynx) which I have, for the convenience of English readers, reduced, as nearly as possible, from centimetres and millimetres to inches.