Part 7 (1/2)
THE LARYNGOSCOPE.
The distinguished physiologist Johannes Muller demonstrated the working of the larynx by special experiments. He fixed into the windpipe a bellows, and showed, in the dead larynx, of course, that the blast from this source could cause the vocal bands to vibrate and thus produce sounds, which by varying the strength of the force, etc., were made to vary in pitch.
While such experiments indicate the essential principles of a possible voice-production, as the conditions in life were not and could not be fully met these results were rather suggestive than demonstrative of Nature's methods. These investigations served a good purpose, but they were manifestly inadequate, and this was felt by one thoughtful vocal teacher so keenly that he pondered much on the subject, in the hope of finding a method of observing the larynx during actual phonation. To this distinguished teacher, Manuel Garcia, belongs the honor of inventing the means of observing the vocal bands in action.
This was accomplished in 1854, and, soon after, Garcia read an account of his observations to the Royal Society of London; and though much in this paper required correction by subsequent observations, it remains to this day the foundation of our knowledge of the action of the larynx in voice-production.
[Ill.u.s.tration: FIG. 38 (Bosworth). Intended to ill.u.s.trate the optical principles involved and the practical method of carrying out laryngoscopic examination. The dotted lines show the paths of the light-rays.]
As usually employed, the laryngoscope consists of two mirrors, the head-mirror, so called because it is usually attached to the forehead by an elastic band, and the throat-mirror, which is placed in the back part of the mouth cavity. The purpose of the head-mirror is to reflect the light that reaches it from a lamp or other source of illumination into the mouth cavity so perfectly that not only the back of the mouth, etc., but the larynx itself may be well lighted up; but inasmuch as this illumination may be accomplished, under favorable circ.u.mstances, by direct sunlight, the head-mirror is, though mostly indispensable, not an absolutely essential part of the laryngoscope.
There is, indeed, one advantage in the use of direct sunlight, in that the color of the parts seen remains more nearly normal. Lamplight tends, because of its yellow color, to make parts seem rather of a deeper red than they actually are; but this to the practised observer, always using the same source of illumination, is not a serious matter--his standards of comparison remain the same. Moreover, this objection does not apply equally to electric light, now so much used.
[Ill.u.s.tration: FIG. 39. This ill.u.s.tration is meant to show more especially the relative position of observer and observed. The observer, on the right, is wearing the head-mirror, while two throat-mirrors seem to be in position--in reality, the same mirror in two different positions. One is placed so as to reflect the picture of the nasal chambers, especially their hinder portion. The walls of the nose, etc., may for the purposes of this ill.u.s.tration be considered transparent, so that the scroll (turbinated) bones, etc., come into view. The tongue is protruded. The light, not seen in this figure, is usually placed on the left of the subject, as in Fig. 38.]
It being a fundamental law of light that the angle of reflection and the angle of incidence correspond--are, in fact, the same--it was necessary that the throat-mirror should be set at an angle to its stem, so that the light pa.s.sing up by reflection from the larynx should, when striking on the surface of this plane throat-mirror, be reflected outward in a straight line to the eye, which must be in the same horizontal plane with it. This and all the other facts and principles involved can only be understood by a careful inspection of the accompanying figures, which it is hoped will make the subject plain. The throat-mirror is none other than the mouth-mirror of the dentists, and in use by them before Garcia discovered how it might be employed to throw light on the larynx, in a double sense.
The essentials, then, for a view of the interior of the larynx are: A source of illumination; a mirror to reflect the light reaching it from this source into the back of the throat and larynx; and a second mirror to reflect the light outward which is, in the first instance, reflected from below, from the interior of the larynx. The principles involved are few and simple, but their application to any particular case is not easy, and is sometimes well-nigh impossible.
The throat-mirror should be placed against that curtain suspended in the back of the mouth cavity known as the soft palate, so that it must be pushed back out of the line of view. But many persons find such a foreign object in the throat a sufficient cause of unpleasant sensations so that retching may be the result. Generally there is a tendency to raise the tongue behind in a way fatal to a view of the mirror and the picture reflected from it. These difficulties, however, can be overcome by a deft hand using the mirror brought to ”blood heat” by placing it in warm water or holding it over some source of heat, as a small lamp, and directing the subject observed to breathe freely and _through the mouth_. This latter tends to quiet that unruly member, the tongue, and lead it to a.s.sume the flat position so important to an un.o.bstructed view. It is for the same reason the author urges mouth breathing during speaking and singing. No other tends so well to put the tongue in the correct position.
The extent to which one feels the annoyance of a small mirror held gently in the throat depends really on the amount of attention directed to it, and the degree of determination with which he resolves to exercise self-control. The author has examined an entire cla.s.s of students of voice-production and found only one person who did not succeed in at once giving him a view of the larynx. But it must be at once said that of all persons examined by the author during his experience as an investigator of voice-production and in special medical practice, none have been able to show their throats, the larynx included, so well as speakers and, above all, singers; which in itself indicates that speaking and singing do give control of the throat--that all its parts respond to the will of the observed person.
The author must further, however, remark that he has found this control a.s.sociated not so much with vocal power as with intelligent study. Intelligence tells in music a good deal more than many people have yet learned to believe; but on this point the reader will long since have learned the author's views--in fact, so deep are his convictions on this subject that he hopes he may be pardoned for frequent reference to them, in one form or another.
One anatomical fact may be so invincible that a view of the glottis cannot be obtained at all: the epiglottis may so overhang the opening to the larynx that a good view of its interior is absolutely impossible, in other cases only occasionally and under very favorable circ.u.mstances. Such cases are, however, of the rarest occurrence, while there are not a few persons in whom one may even see down the windpipe as far as its division into the two main bronchial tubes, and inflammation may thus often be traced from the vocal bands far down the mucous membrane common to the larynx, windpipe, etc.
As has been remarked previously, it is only by the use of the laryngoscope that one can see the vocal mechanism of the larynx in action, so that for investigation laryngoscopy is essential.
Auto-laryngoscopy, or the use of the laryngoscope by the subject to observe his own larynx, has its special difficulties and advantages, the greatest of the latter being, perhaps, that the observer may use himself as often and as long as he will, while he would hesitate to make observations on others at great length or with frequent repet.i.tion. There are no new principles involved in auto-laryngoscopy.
The observer must simply see that a good light is reflected into his own throat, and that the picture in his throat-mirror is reflected into another into which he may gaze, an ordinary small hand-gla.s.s usually sufficing.
Only rarely is the individual met who can himself so control his tongue that a.s.sistance from the observing laryngologist is unnecessary. In by far the greater number of instances the tongue, after being protruded, must be gently held by the left hand of the observer, a small napkin covering the tip of the organ. The auto-laryngologist must, of course, control his own tongue, and better if without any hand contact.
It is scarcely necessary to say that before placing the mirror in the mouth its temperature must be tested by touching it for a moment against the back of the hand.
Nearly all the facts of importance in phonation, several of which have already been referred to, or will be mentioned in the ”Summary and Review” below, could only have been discovered by the use of the laryngoscope. The difference in the larynx in the two s.e.xes and in different types of singers and speakers, though open to ordinary observation, dissection, etc., are still better brought out by the use of the instrument now under consideration.
One naturally expects any organ to be larger and heavier in the male than in the female, and to this the larynx is no exception; and individual differences are equally p.r.o.nounced. There may be almost if not quite as much difference between the larynx of a barytone and of a tenor as between that of an ordinary man who is not a public voice-user and the larynx of the ordinary woman. The larynx of the contralto may in its size and general development remind one of the same organ in the male. The vocal bands of the ba.s.s singer may be to those of a soprano as are the strings of a violoncello to those of a violin--using these examples, it will be understood, merely as rough ill.u.s.trations.
The change in the size of the larynx produced by even a few months'
judicious practice may be astonis.h.i.+ng. As already hinted, it is important that in bringing about this development exclusive attention should not be given, as is sometimes done, especially in the case of speakers, to the lower tones, though it is not so important for them as for singers to have an even development up to the highest range.
But again the author would urge the voice-user to aim at attaining that delicate control of muscles (neuro-muscular mechanisms, to speak more scientifically) so important for the finest vocal effects, rather than be satisfied with mere power. The vocalist and speaker must indeed be athletic specialists, but they should not aim at being like the ordinary athlete, much less mere strong men of the circus.
It is said that Madame Mara within her range of three octaves could effect 2100 changes of pitch, or 100 between each two tones of the twenty-one in her compa.s.s, which would represent a successive change in the length of the vocal bands of a small fraction, possibly not more than 1/17000 of an inch--something unapproachable in nicety in the use of any other instrument. Even if we make large deductions from the above, the performances of those who have reached the highest laryngeal control must remain marvellous, all the more when it is remembered that this control over the larynx, to be efficient for musical purposes, must be accompanied by a corresponding mastery of the art of breathing. Is it necessary to point out that such wonderful development and control can only be attained after years of steady work by the best methods?
At one period in the life of the individual changes of such importance take place in the entire nature, physical, mental, and moral, that he becomes almost a new being. This epoch is known as the period of p.u.b.erty or adolescence, and may be considered that of the gravest moment during one's whole life; for then, for better or worse, great changes inevitably occur. It is incomparably the period of greatest development, and, unfortunately, there may also spring into being, with striking suddenness, physical and psychic traits which cause the greatest anxiety. In any case, the thoughtful must then regard the youth or maiden with feelings of the deepest interest, if not anxiety; and in the case of the voice-user, especially the singer, this period may come laden with the destinies of the future.
The vocal organs, especially in males, undergo very marked changes in relative proportions and actual growth. So marked is this that the boy soprano may actually become a barytone, or, unfortunately, no longer have a singing voice at all.